JR's rail grinding skate in a Lasered & Bent format for 4.5" grinders

[Gerald D]

Here is a proposal to laser cut the original concept of JR's skate (http://www.mechmate.com/forums/showthread.php?t=19) . . . . . .

To talk about the skate in general, I don't see the need to have adjustments for both:
- adjusting the top wheel height by eccentrics/levers, as well as
- screws to move the grinder from side-to-side.
One of these methods should be sufficient - my preference is to move the grinder because it is less sensitive and more rigid.

Also, do we really need wheels on top for making one set of rails? Can't the bottom of the skate just rub on top of the rail? How about brass screws up into the bottom of the skate and let the screw heads rub on the rail top? (the grinding throws up a small burr which will chew the brass to some extent, but rather not have a hard "screw" which could wear down the narrowing reference surface on the top of the rail)

Double plastic handles would be a total luxury - I would manage to produce one set of rails without handles, or maybe just one crude steel bar...

Clamping the grinder by only using its handle screw holes would be a non-starter for me - the only rigid place to hold a baby grinder would be directly behind the disk onto the gearbox. With most of these grinders now coming from the East, those screws are likely to be metric. (The Bosch is 4mm)

The four main rollers would logically sit on the same eccentrics that are going to end up on the Z-slide. No need for special eccentrics for the skate. A pair of 6001.2RSR bearings would make a nice roller. Those bearings could be re-used if making your own V-wheels as per M1 20 120.

I am toying with a design and laser cutting for the skate, but I am not yet convinced that everyone can easily find the same Bosch grinder. Also, I don't know if the grind-wheels/disks have the same thickness/offset/depression around the world.

[Gerald D]

Right-click and save the attached file to Grinder04.dxf and open with CAD program to see where my thoughts are heading . . . .

Faulty file deleted

[gmessler]

That looks Great Gerald!! :)
What about fine adjustment ability to the 45 angle?

[Gerald D]

Shims

[smreish]

...okay - That's so simple I love it. Darn your good.
I will let you know how it turns out, I am going to have that made by next week and grind my rails with it.
Sean

[Gerald D]

Sean, I look forward to your feedback!

Here is a scheme that incorporates a little angle adjustment - also makes the skate stiffer . . . . .

(Remember to save as a .dxf file)

Faulty file deleted

[smreish]

Gerald,
I will be glad to update you on the work up. I like today's additions to the skate. I actually added 4 tapped holes to the grinder plate with allen head set screws to add "shimming" adjustment. I like the bolt like outrigger a little better than my set screws.
I also have redrafted the grinder plate to fit my Ryobi AG402 model grinder. It has the same bolt circle as the Bosch, just a slightly larger clearance for the gear head armature. I hope to have a working sample for you by monday. I am out of town the next couple of days, so I will not get back to making the grinder until saturday.
Cheers. Sean

[Gerald D]

Just some more to break out of the fixed line of thinking . . . . . .

501

[Dirk]

Gerald,
On your above illustration, how would you do both sides? It looks like the bearings will hit.
Dirk

[Gerald D]

Swop the spacers to the other side after doing the first sides of the rails. (yes, that will involve re-adjusting the eccentrics, but that shouldn't be a problem)

This might be a more stable way of "clamping" to avoid "rocking" - if indeed there is any rocking. I would try this before "outrigger" wheels.

[driller]

Maybe the grinder could be mounted on a shoe that is bolted to the skate.

that would let the skate be fixed, and the grinder could be reversed with just a couple screws.

Dave

[smreish]

I built the Beta version of the skate from Gerald's plans.

DO NOT USE the BETA drawing files if you have them - A few modifications are necessary.

I have to say - it works really well.
I did have to do a few tweaks, but they were minor. Gerald, I will have to send you the dwg file I updated, the hole centers need a little adjusting.

The good.

- easy to fabricate
- Instead of laser cutting, I just printed the dxf file full size and spray glued it to a piece of "COLD" rolled 1/4" plate and worked from it.
- drilled all the holes
- cut along the lines with a band saw.
- after all machining and dressing, I parted the plate on the bend line and then welded back together @ 45 degree angle. Simple, quick...
- Welding hardened the plate which made re-drilling a couple of holes REALLY hard. (I guess I shouldn't have quenched it to be in a hurry:)
- adjusting nut/rod assembly aft of the grinder is amazing. Super easy to set the grind angle. Bravo.

In the photo's below, I haven't even adjusted the grind angle yet and it's almost dead on perfect from the assembly setup.

The challenges.

- the eccentric bolts from Superior are 12mm - not 1/2" as indicated. Thus, I had a bearing problem that I ordered from VXB. If you order your bearings, make certain that you get 12mm ID - NOT 1/2" To correct this I had to make up a .030 flanged bearing sleeve. Not fun, but not a hurdle either.
- Brass bolts for height adjustment....they wore down after 1 pass and were sticky to move on. Changed to Hardened Stainless Steel.....zippie skippy! Yahoo.....worked like a champ!
- I don't have a bosch grinder like Gerald, but the home depot Ryobi AG402 has the same bolt circle as the bosch. To use the Ryobi, you must enlarge the clearance hole to a slightly larger diameter and add 1/4" standoffs to the frame for the plate to bolt down securely. All in all, easy change.
- have to add a guard. It's really easy to want to grab the grinder body to push with. Glove's and the proper safety gear was a blessing today.

I have 2 really nice handles that will go in the holes just below the adjusting rod. This will keep my hands on centerline. I will post photo's of it with the rail grind later in the week.


The pictures tell the rest of the story.

[Gerald D]

Picture no.3 . . . . . never in my life have I seen such a collection of screws, nuts and washers! :D:D
(Wouldn't say this is one of my prettiest designs, but rates high on function.)

Sean, glad to hear we are heading in the right direction. I can't believe I got those hole centers wrong while the ones for the long screws actually worked out :o

Is there enough space to remove the disk? Somebody will assemble the whole skate before they put the disk on.

The hole can be enlarged for the larger grinder, but I think to leave surplus metal at the back for each user to trim to his own grinder.

Before someone asks, the unused holes in the top pic are for when grinding the height of the rail down......when the grinder is rigged horizontal to the table

The correct bearings for the wheels on the eccentrics are 6001-2RSR

[smreish]

Gerald,
I have already transfered the hole pattern on the front to the "moving bed" for the cutting down sequence. I knew what they were for the moment I saw them....like the trash can thread you had started a few month's ago!

My craftsmanship on the band saw was a little shaky! I didn't have the correct saw tooth arrangement and I was forced to be a little aggressive in my cuts! That plate looks I had it for lunch:)

I'll try removing the disk soon and let you know.
This one's a winner. I have added the Bosch layout with the adjusted holes to the laser part list. If you have any further corrections, I will add them too.
Sean

[Gerald D]

Took me a while to figure out the reference to "trash can" . . . . . . . aaha! the background of these pics (http://www.mechmate.com/forums/showthread.php?p=351&postcount=1)! :)

A safe(ish) "handle" could be formed by enlarging the upper plate and bending its lip up. I havn't got the feel of the device, so I don't know quite where one has a tendency to grab it.

Hardened stainless screws are a bit exotic for the average DIY guy. Would standard allen cap screws do? (Allen caps are a good bit harder than normal screws).

[Marc Shlaes]

Sean,

I was also wondering how you held the tool. Looks simple and effective.

Good show Sean and Gerald!

[Gerald D]

Could screw a standard handle or two onto some of those protruding threads:
545

[pksharma]

Sean.
I think the pair of bearings should have a nut in between to keep them apart enougn to hold angle better. This stops tilting of grinder. Also as Gerald said grinder wearing be considered.

PK

[Marc Shlaes]

PK,

You really can't do that. You will need to make the rail higher and that will change a bunch more parts. I believe (I could go look but I'm in a hurry) that the rail height is 1.125 inches or about 28mm. There is barely clearance for the two bearings. The sample that Sean ran in the picture is prior to cutting the rail down to the correct size. I'm sure that he was testing the tool on "scrap".

[Gerald D]

PK, this design started in these threads:
http://www.mechmate.com/forums/showthread.php?p=5297&postcount=36
http://www.mechmate.com/forums/showthread.php?p=5766&postcount=8

Now that Sean has kindly proved the concept for us, I will try to tidy up the threads a bit.

[smreish]

PK - Marc is spot on...the grind profile you see in the picture is on a native 2.5 x 2.5 x .25 angle iron before cutting it down to the required new Beta height of 1.1" tall. As a matter of fact, the 5/16" #3 phillips screws you see in the picture are actually .05" to tall to actually work on the real rail height. I have ordered the correct button head allen screws for the final working model.

Gerald, the SS - 1/2"-13 grade 8 is just something I had on hand in the hardware bin...I am certain anything fairly hard will work. I will try a normal grade 3 zinc tomorrow and let you know how it "feels".

The handles you propose "feel" about the right size and angle. In use, you feel like a lumber jack using a big 2 person BUCK saw....a nice 45 degree grip angle feels pretty nice to "saw" along the angle with. I will snap a pic with the handles attached tomorrow as well.

[pksharma]

Sean,
Please advise me, I have purchased Chinese angle grinder 450W. 10000 rpm with metal body and plastic tail handle. Is it ok for above taper cutting and grinding of angle ? or should I buy costlier one (which is 4times costlier than this)

PK

[smreish]

Pk,
Based on the limited information on your post I cannot advise you yes or no.

[Abdul]

pk.

I have similar grinder works fine, don't press hard against steel, use its weight only for cutting. One thing about Chinese if they keep working long time they work oterwise they don't work at all or become useless within no time.
Abdul

[smreish]

...a quick note on the Mamba Skate.
- today I cut down all the rails with the top half of the skate.
I attached it to a plywood shoe with 4 bolts sitting up to allow for pitch and yaw correction on the cutting wheel. Worked exceptionally well.
I will post pics next week when I get back in town.
- If you go back to JR's and Gregs posts, you will see a cutting sled example that I worked from.
NOTE: DO NOT try to cut to much at one time. I tried to beat the 5pm clock on friday and got a little agressive on my final pass......Cost me a smoking grinder. Good thing I bought 2 earlier in the season for the MM project!
If I have time, I will start putting the profile on tomorrow, if not, it will be another week before you hear anymore news.

Sean

[Greg J]

Sean,

Whats your rail height?

I never could fabricate a set of rails with my skate. My rail height is 1.00 inch. Finally end up having a friend with an end mill make the X and Y rails. It took him about a month and not the best quality. I wasn't happy with his invoice either.

A real machine shop is fabricating the Z-slide. Should be ready Tues or Weds.

[smreish]

Greg,
I cut the rails to 1.25" I will now surface grind them to 1.200 flush out any small imperfections in my cutting before I "skate the profile".

Yes, the rails area a little taller than specified on the print, but the swing angle of the motor mounts is adequate for this small adjustment. I will say, it's pretty easy to cut the rails down....it just requires patience. And a spare mini grinder:D

For those making the MM for the first time, I truly recommend using the 8" channel section as your workbed for the grinding, cutting and such. It makes a really nice "flat" surface to work on.
I know JR referenced this in his build, but I truly believe that using the Channel as a work surface is necessity to getting the deck height correct.
I already built the table at this point, luckily, I had plenty of Large steel laying around in the shop to use as a 20' long workbench.

[Digitize]

Has anyone considered using a MechMate setup properly with a grinder to make the rails for others in their area? I believe that is what ShopBot did at one time to make the rails for the PRT. With the necessary shims the rail can be leveled properly and the tolorance for the 45 degree angle can be controlled very well. Just a thought....

[smreish]

Steve,
Funny you mention using the table itself to make the rails...something truly worth trying once I have the first table built.

For those watching from the couch,
I was able to mount the cut rails up on the machine today and starting grinding the profile.

The mamba skate works really well, and at this time appears to have ample clearance with the new 1.125" tall rail section. PLEASE NOTE - my rail right now is 1.25.

Gerald, you asked me weeks ago if you could change the grinding disk once the skate is completely assembled. The answer is no. A small clearance cut must be made in the back of the skate to get the disk to "hop over" the mandrel on the grinder. The bosch might have a slightly shorter shaft and work. My Ryobi is about 1/16" short of making it. A little grinder action fixed the problem. When I have a real life clearance drawing, I will forward it over for you to look at.

On the up side,
I have pictures below to document the progress of the Beta MM Mamba Skate. I have tack welded a fender washer at the end of the rails to keep the skate from falling off. When the rail is complete, I will cut off the rail and that 4.5" of waste will fall off.
By the way, cutting note.
I cut my rails to the following length....
12' 8" and 7' 6".....My angle iron in Florida always comes at least 1" long if not 2"...so I was able to get the rails for a 60" x 120" machine out of 2 lengths of steel.

Back to doing stuff while my wife and I are busy waiting for our new baby girl to arrive.....contractions and working do not go well together. Thank goodness the MM is a good diversion to the waiting game.

Sean

[smreish]

Grinder skate modifications not necessary. I was easily able to get all of the rails ground with one grinder disk. The form factor of the Mamba skate is so small, you have to assemble the 2 halves and mount the disk at the same time. I went ahead and changed the disk for giggles and found that it was REALLY easy to change the disk, re-tighten the skate, and go about grinding again without much readjustment at all.

Total time with the skate to grind (only grind) was about 1.5 hours per rail...not bad. I could have gone quicker, but I chose not to even tempt fate and overheat the surface of the rail or burn up another grinder :eek:

Little note on making the skate slide easier....the 1/2-13 UNC bolts for vertical adjustment...it's not reflected in the above picture, but it was necessary to grind a small crown on the end of the bolts to keep the threads from wanting to dig in the rail surface. It only happened when I reached the adjustment part that let the lead of the threads be perpendicular to the rail. A quick grinder wheel action and I was back in business. oh Yeah...the fender washers on the end are a true asset to the grinding step! Easy peezy lemon squeezy.

It's kinda fun being the guinea pig for a BETA part/tool!

I will write a summary of the grinding experience for the future users.


Sean

[Marc Shlaes]

There are a lot of inspirations in this MechMate Community. Sean, you surely are one of them.

With you, JR, Mike Richards, Gerald, Fabrica, Doug Ford, and Greg J leading the way, us mere mortals have a chance of success. Thanks!

[Gerald D]

Good feedback Sean!

Where did you find yourself holding the skate? Did you feel the need for handles? Did you think the thing to be dangerous in any way?

All the above for the red notes to be added to the drawing! :)

Marc, those guys on your list considered themself as mere mortals in the beginning as well - it is a state of mind to break out of. (Was very impressed by Doug who started off all meek and mild with electrics, and then recently he tells a guy how to parallel a transformer - wish I had that courage! :))

[Gerald D]

Little note on making the skate slide easier....the 1/2-13 UNC bolts for vertical adjustment...it's not reflected in the above picture, but it was necessary to grind a small crown on the end of the bolts to keep the threads from wanting to dig in the rail surface. It only happened when I reached the adjustment part that let the lead of the threads be perpendicular to the rail. A quick grinder wheel action and I was back in business.

Remember our earlier discussion on a brass screw? After some real time on the skating, don't you think a brass screw with a crowned tip (hand-ground) would be better? That would be on the soft side to prevent damage to the reference surface on the top of the rail.

Or, to prevent stickyness between the steel screw and rail (galling?), one could try and go over to the really hard side for the screw. How about a capscrew (they are a tough steel usually) with a crowned tip?

JR, you know your metals, what do you think? (aside from a ball bearing, which is obviously the best ;))

[J.R. Hatcher]

Sean when the rail is finished and the skate is still in place, how much space is between the top of the rail and the bottom of the skate? In other words how much of these adjusting bolts do you see? What is the size (diameter) of the adj bolts?

I'm thinking if you used a small adj bolt, maybe 10-32 and there is enough space between the rail top and the skate bottom you could use a acorn or cap nut (bottom it out on the bolt, the bolt would still be the adjustment). You could try brass, steel, nylon or chrome to see which one worked the best. They would already be rounded and easy to replace when they wear.

http://base.googlehosted.com/base_media?q=http://www.campmor.com/images/acc/70031.jpg&size=2&dhm=759d2897&hl=en

[smreish]

JR and Gerald
I tried a bullet tip socket head cap screw and worked perfectly! The brass bolt really deforms quickly. I will post pics when I get to the office.
The cap screw is something I tried a few weeks ago on scrap and was great. The only challenge was I only had 1 in the shop and I forgot (kept forgetting) to get more in. My brain isn't totally with me these days. :)
sean

[Roadkill_321]

. . . . . .Next on the agenda is to get the grinder skate working. I have to make some modifications to it to work with my grinder, but they will be minor mods. The eccentrics will have to be made by a local machine shop if they have the time to do it. . . . . .

[Gerald D]

Remember that the eccentrics for the grinder and the eccentrics for the z-slide are the the same ones. First use them in the grinder and then move them to the z-slide. The grinder uses 4, the Mamba z-slide uses 6. Get 6 made, if you havn't purchased them from Superiorbearings yet.

[Roadkill_321]

Gerald,

I've already got the kit that Superior Bearing offered, and I think that it has six eccentrics in it. That's great if they will also work in the grinder skate. If I remember correctly the bearings are 6001?

John

[Gerald D]

Yes, 8 off 6001 bearings sealed against the grind dust. 6001.2RSR is a typical number for a sealed bearing (12mm ID, 28mm OD, 8mm Width). Yes, they are metric bearings, but the Superior eccentrics are also metric.

[dmoore]

SuperiorBearing.com (where you can also order your v-Roller bearings and bushings) also carries the bearings for the skate. You will need 8 of the 6001-2RS and they are $2.45 each. These are sealed on both sides. You will not need the bushings as you can re-use the ones from the z-slide bearings.

These bearings can also be purchased from McMaster-Carr (www.mcmaster.com (http://www.mcmaster.com)) for 6.43$ Part Number: 5972K82

[dmoore]

In the laser cut kit I purchased, I also received the plates for building the skate. When I started to go through the plans, it appears there is a minor missing item (see red boxes on attached image) - the "spacer bolt". The test version appears to have the "spacer bolts":

http://www.mechmate.com/forums/attachment.php?attachmentid=548&stc=1&d=1194372844.jpg

It's not a major issue - I just though it might throw some people off if they just looked at the drawings.

Also, there was some discussion of adding handles to this "spacer bolt" to better support and angle the grinder - was there any final decision?

Much thanks!
david

[dmoore]

Yes, 8 off 6001 bearings sealed against the grind dust. 6001.2RSR is a typical number for a sealed bearing (12mm ID, 28mm OD, 8mm Width). Yes, they are metric bearings, but the Superior eccentrics are also metric.

In talking with Rick from Superior Bearings, I was refering to the double-vee bearings as 12mm metric (bore) and he mentioned they were not metric - that his supplier sells an actual metric version of the same bearing. I find this odd since .472440" IS 12mm. He must be right since GW2 is .3750 (9.52mm). Though GW4 is .5906 which is 15.001239mm. So, technically they are not 12mm but in reality they are. Odd...

http://www.superiorbearing.com/images/guidewheels_wheels_chart3.jpg

[dmoore]

There is not a parts list for building the rail skate M610100A so I did my best to make one up:

Bosch Grinder (US): 1347A
Bearings: 8 of 6001 Bearing (12mm ID, 28mm OD, 8mm Width (www.superiorbearing.com (http://www.superiorbearing.com) part 6001-2RS)
Eccentric Bushings: 4 of M1 20 210 T (www.superiorbearing.com (http://www.superiorbearing.com) part B3X)
Bearing Posts: 4 of 5/16" x 2" long - Pan/Flat head
Bearing Posts: 4 of 5/16" nuts
Bearing Posts: 4 of 5/16" washers
Plate bindings: 2 of 5/16" bolts
Plate bindings: 4 of 5/16" washers
Plate bindings: 2 of 5/16" nuts
Angle Adjustment: 2 of 5/16" x 3" full body thread
Angle Adjustment: 6 of 5/16" nuts
Angle Adjustment: 8 of 5/16" washers
Rail Rider Height Adjustment: 2 of 1/2" x 1 1/2" Stainless Steel Bolt (requires drill/tap hole to 1/2")
Rail Rider Height Adjustment: 2 of 1/2" nuts

http://www.mechmate.com/forums/attachment.php?attachmentid=547&stc=1&d=1194372830.jpg

[lunaj76]

David,

Are you sure the Bosch 1347A will work? We bought the 1710 because the 1375A didn't work with the skate. The 1710 has a 7.5 amp motor.
Thanks for the lists!


http://www.toolking.com/category/power-tools/grinderspolishers/angle-grinders-4-inch---45-inch.aspx

[Gerald D]

David was probably (mis)lead by:

Do you all have any of these Bosch 115mm [4.5"] 11 000 rpm grinders easily available in your country?:
(all appear to have have similar aluminum gearheads)

230Volt countries (http://ukptocs.bosch-pt.com/boptocs-uk/Category.jsp;jsessionid=031C42B39A8D1194E52058227C 980C55?division=gw&ccat_id=81919):
GWS 11-125 (1100 Watt) (125mm)
GWS 10-125 (1000 Watt) (125mm)
GWS 9-125 (900 Watt) (125mm)
GWS 8-115 (800 Watt)
GWS 7-115 (750 Watt)
GWS 6-115 (650 Watt)

115V countries (http://www.boschtools.com/tools/tools-subcategory.htm?H=175975&G=59730):
1810PS (8.0 Amp)
1810PSD (8.0 Amp)
1800 (7.5 Amp)
1375A (6.0 Amp)
1347A (6.0 Amp)

I could design a system that fits to their gearheads . . . .

Justin, are you saying that the 1347A had a different gearhead that would not fit the lasered skate? How well did the 1710 fit? Realise that I have never done it myself . . .

Is there a 1710 model? I only see 1810.

[lunaj76]

I believe we checked the 1375A it could have been the 1375-01. It had a 6Amp motor and didn't fit lasered skate. If you use my link and go to page 2 you will see the 1710 this is the one we purchased (fit perfectly). We did not check the 1347A. Just wanted to make sure the 1347A did work.

[dmoore]

Thanks for the update! I'll update my "master" BOM.

[dmoore]

The mamba skate works really well, and at this time appears to have ample clearance with the new 1.125" tall rail section. PLEASE NOTE - my rail right now is 1.25.


Sean -

You mentioned that you changed your rail height to 1.25" instead of the 1.10" (28mm) in the plans. Did you change this because you could get angle in 2x1.25"? Having already tried cutting the rail down and failing, it seems the best solution is to just use rail that is already the right height - which here is 2x1.25" (they don't have 2.5"x1" or 2.5"x1.25"), then grinding it down from there. Of course this changes a few other things but it seems other than the motors dropping down, nothing major. Any suggestions are welcome!

Thanks,
david

[Gerald D]

The motors drop down and the stop blocks inside the rails need to get taller.

The secret to cutting the rail down is a quality cutting disk. See posts #87 to #90 in this thread (http://www.mechmate.com/forums/showthread.php?p=9557). The equivalent disk in the USA appears to be EDP #63157 on this page (http://www.pferdusa.com/products/206/20615/206150201P.html)

[dmoore]

I've come up with a solution that seems to solve two problems at once - the grinding down of the 1/2" bolt on the ends of the skate that ride on top of the rail and a way to hold the skate down and level.

Start by taking a 1/2"-13 bolt and smoothing the head (if it has any part numbers, grade markings, etc) flat. This head will then ride on top of the rail you are grinding. Take the skate an drill and tap for a 1/2"-13 in the large holes on the ends/edges of the skate (your skate is 1/4" thick plate right?). Insert the bolt with the head facing down. This then leaves a stud sticking up. Put a 1/2"-13 nut on this to form a "jam nut". Then you should still have about 3/4" of threaded bolt sticking up. Order two of these: 57455K76 from McMaster-Carr. Problems solved. Note - this should require a little grinding of the top plate to make room for the handles.

Here is a sample photo (less the handles):

[smreish]

Good solution.
I my beta version - before the laser cut profiles - I tried this arrangement.
The head on the adjustment bolt sometimes cleared. I found that the eccentrics when shifted all the way towards grinding centerline there was interference. I am glad it works for you!
Good solution.
Sean

[J.R. Hatcher]

I need info from anyone that has it. How much does the bolt that rides the rail during grinding protrude from the bottom of the plate, from (start) to finish?

[domino11]

Has anyone verified if either the
Bosch
1375A (6.0 Amp)
1347A (6.0 Amp) grinders will fit the skate? I am trying to find one here that will work. Just wondering if someone is using one of these part numbers.

thanks

[Gerald D]

Drawing M6 10 115 Rev A was tailored for Bosch grinders, but folk modified that for other brands of grinder. The Rev B version of that drawing is now more general pupose. I don't think it is critical to get Bosch grinders per se. But I do think it is important to get a fairly high powered grinder because we have had a couple of reports of burnt out grinders.

[jeffh]

Hi Heath, can't help you with the Bosch grinders as I haven't used either of those model numbers but I know for a fact that the recent skate drawings (Not sure of the specific version) also fit the Milwaukee 1648 8.5A grinder perfectly.
(Probably the same gearhead mfg for both...)

just my $0.02 (USD) :-)

[Tailgunner]

Where can i find the latest skate-drawings. The files on the first page are deleted.

[sailfl]

Tailgunner,

The skate drawings are the last drawings in the last PDF of the drawings that you download. M6 10 100 through 10 20 456.

Hope that helps and that is what you are looking for.

[domino11]

The link for the last pdf file is here

http://www.mechmate.com/forums/attachment.php?attachmentid=1699&d=1215014708

The laser cut profiles which have the profiles for the skate parts are here.

http://www.mechmate.com/forums/attachment.php?attachmentid=1676&d=1214853734

[Gerald D]

Food for thought:

3633

If a standard 115mm [4.5"] disk is held vertical, but 45 degrees across the rail, it will cut a 45 degree bevel if the wheel is held 9mm [0.4"] below the top of the rail. The bevel will be slightly hollow, by the amount of 0.044mm [0.002"]

[TonyBert]

Gerald,

The only problem that I see is as the disk wears, the cutting depth will decrease and the wear surfaces will not be the same height along the length of the rail.

Tony

[Gerald D]

For a light final grinding pass, the disk wear is practically zero. That applies to all grinding operations, eg. surface grinders, knife grinders, cylindrical grinders, etc.

[MattyZee]

I've been reading all the posts on the angle grinding as thats the bit thats got me most worried about starting my build. I grabbed my dads grinder to see if it will fit on the skate. It looks like it wont. Its an old Makita...
4227

I thought the skate attached to the equivalent of the 3 screws that held on the safety guard. So then i went down to the local hardware store here and had a look at a few there.
But then i re-read this:
Clamping the grinder by only using its handle screw holes would be a non-starter for me - the only rigid place to hold a baby grinder would be directly behind the disk onto the gearbox.
So do I understand now the skate attaches to the 4 screws that hold the shaft bearing? So do you remove these screws then attach the skate with longer screws? Is there any issue comprimising the grinder doing this? (will it void my warranty if i buy a new one?)

[Gerald D]

So do I understand now the skate attaches to the 4 screws that hold the shaft bearing? Yes

So do you remove these screws then attach the skate with longer screws? Yes

Is there any issue comprimising the grinder doing this? (will it void my warranty if i buy a new one?) Your warranty will be voided if they find out that you have removed the screws. It is not as if you are doing open-heart surgery to the grinder, but you certainly would be using the grinder in a manner it was not designed for.

[vishnu]

Matt just go on, I had to do it in the same manner. Also i was unable to fix my grinder to the small fixing dia on the original skate plate so i had to bore them and cut the end to enable my grinder to sit. I did a small ring washer with a PCD holes of the grinder and screwed them. No problem till the end of the grinding. Lot of R&D is not required just keep going you will learn in a few minutes. Love to see you grinding soon :)

[J.R. Hatcher]

I need someone to look at this drawing to see if my modifications will work or interfere with the workings of the skate. My idea is to use 2 bearings like Joe is shipping with the skate (now we need 10 instead of 8). Cut a length of 12mm rod 1" long insert it through the bearing, then spot weld the ends of the rod to the top of the plate. This will leave 1/16" of bearing protruding under the plate to ride the rail. Now all adjustments will need to be made by adjusting the upper plate in and out on the lower plate.
I also have some ideas about fine adjusting the plate, but I would like to know first if the modifications will even work.

[Lex]

I haven't decided yet on how I am going to grind my rails. With the skate or other guiding method.
I think this idea of yours will work. It will eliminating the damage to the riding bolt.
What did you had in mind for adjusting the height, J.R.?

[J.R. Hatcher]

Johan it will be easy, we will just adjust the top plate more toward the center.

[J.R. Hatcher]

I need help identifying the purpose of the 6 holes circled. Thanks

[Gerald D]

If you look at Sean's pics in earlier posts in this thread, you will see a pair of "all-thread" rods lying at 45 degrees to the base of the skate. They are for fine tuning the 45 degree angle when bevel grinding.

The remaining pair of holes (out of the 6 marked above) are a place to screw on handles.

[smreish]

link (http://www.mechmate.com/forums/showthread.php?p=6111&postcount=49) for the skate pictures and details.

[Lex]

Hi JR,
My boss left me alone last week so that I could enjoy my coffee during my lunch times. I was playing a bit with your new idea for the skate.:) Hope it it is ok?;)

4914

4915

4916

4917

4918

The existing plates are shown as per dxfs and I only removed the piece for the existing bolt - height adjustment.
It seems that the best position for the new bearing shaft center could be at the center of the bottom plate.
Only one bolt is shown in position for the bolting the two plates.
The two plates might have to be altered to allow for more adjustment towards the centre.
What do you think?

[Gerald D]

We could put a notch into the skate ends to accommodate the roller bearings. . . . . or the bolt, that is relatively simple and doesn't remove any functionality we have now.

However, that aspect of the skate (sliding bolt head vs roller) is not the highest concern for me. I would rather make a mod that stops the glazing of the face of the grind disk, ie. to make the grinder "attack" the rail at a more aggressive angle. This could involve swivelling the upper plate instead of a straight left to right adjustment.

A snag with the left/right/swivel adjustment is to get a fine control (that we have with the rubbing bolt head now)

[Alan_c]

Johan, that looks good, only one issue - on image 3 I see the lower bearing sets are set at different heights, this will cause problems when turning the skate around to do the inside, its best to have both sides set to the same height. I know that as you drew it would give the best support but everytime you turn around you would have to change bearing positions.

When grinding the bevel, you do one side, turn the skate around and do the other side, when it moves up and down without making anymore sparks, the skate is adjusted for more "bite" then the process repeated again and again and again...etc

[Gerald D]

The skate's "grip" or "pinch" on the vertical part of the rail will also be firmer if the roller pairs are opposite each other. ie. set at the same height.

[Lex]

Thanks Gerald and Alan. That make sense.
I received a quote for R45 per bearing. To buy the 8 to 10 bearings for grinding only seems to be expensive. I do not have a long flat surface on the other hand to grind like Hennie did his.

[Alan_c]

Your'e being ripped off, those bearings should cost no more than R8.00 - R10.00 each, find another supplier (Bearing Man or Bearing Distributors are two I can think of)

[Lex]

Thanks Alan. I will phone around.

[Lex]

Alan, some feed back on those bearings. One of the well known bearing manufacture - suppliers gave me a price of R11.55. Bearingman was the expensive one.
It is the old Zululand way of doing business again. If it is not a shelve item that someone use a lot then they charge 3 to 5 times the price.
The only time that I wish I lived in the city! :)
I was just lucky that the other supplier had some left over from a large order.

[J.R. Hatcher]

Johan I don't know how much trouble it is to redraw this thing (by the way it looks great) but here are some more mods. It is a DXF file so change the ext. from TXT back to DXF. Thanks

[Lex]

Not to much work JR. Geee did I say that! One will never hear words like that from a draughtsman!:D Please don't tell my boss!

[J.R. Hatcher]

By the way, these last modifications are based on the ideas from the last few post by Johan and Gerald. I said it once and I'll say it again ...... "none of us is as smart as all of us" or something like that. You get my drift ... right. ;):cool:. Thanks

[Gerald D]

JR, my AutoCad refuses to open that. (after changing txt 2 dxf)

[Lex]

It opened in mine Gerald. It might have been save in a newer version?

[Gerald D]

Johan, can you mail me a dwg or dxf compatible to AutoCAD 2005?

[Lex]

I only put some bolts in JR. I still have to tweak the roller heights and positions

4926
4927

[Gerald D]

Thanks for trying Johan, but I still get this error message:
Unknown value "AC1021" encountered in drawing version.
Invalid or incomplete DXF input -- drawing discarded.

[J.R. Hatcher]

Good job! You nailed it. Thanks

[domino11]

JR,
Silly question but how are the rail rider bearing held in the skate? I dont see a way to get a bolt in there?

[J.R. Hatcher]

Tack welded. If you ever needed to modify the thing or change bearings, just cut the weld. What do you think ... keep it simple

[J.R. Hatcher]

I know ... I know ... keeping it simple was leaving it alone. I just couldn't do it. Sorry :o It's that type A personality. ;)

[domino11]

That sound fine to me. What about height adjusting? Or maybe its a non issue if you can tilt the grinder with the new hole arrangement?

[J.R. Hatcher]

Gerald is this what you had in mind? This way a person, depending on their skill could either weld a nut in place or do the mods and weld the bearing. Believe it or not the nut can be either a 12mm or .5" they are exactly the same outer measurement.

[Gerald D]

That's the type of thing I was thinking of! But not as clever as that! :)

[J.R. Hatcher]

Gerald I saved it as Autocad 2000.

[smreish]

okay....that's just darn elegant. Kudo's JR.

Nice.

[Gerald D]

Thanks JR, that file read fine this time. (What CAD program are you using).

I would be happy to incorporate a mod like that into the skate parts.

Before changing that, I would like to ask all the folk who have used the skate; what problems did you have and what improvements can be made? I recall someone had a mod to change wheels after assembly. Then there is the issue of guarding the hand. Handles, etc. What needs to be done? Let's catch all the mods now.

[Lex]

I think we need to take another look at the position and spacers used on the side bearings as shown in Gerald sketch in post #8. This might efect the distance that the grinding disc is away from the rail.
I must say that people on this forum works very well together in solving problems. It is part of my job to work with project teams to solve design concepts and problems. One only need one dominating person to destroy that fine sharing balance in a team. I have seen it happen so many times. Nothing like that here.:cool:

[J.R. Hatcher]

Thanks Sean.

Gerald I use Turbocad ver 15

Johan you are right we are a good team, one I'm proud to be a part of.

[MattyZee]

I didn'y make any mods to be able to change the disc but i sure wish you could have when i was doing my grinding. Also definately think a safety guard should be incorporated somehow. Sorry, don't have any solutions, just confirming a couple of items on the 'wishlist' Gerald started.

[smreish]

The mods I made to my beta version of the skate had the back removed for disk change. I'll try to find it out in the shop and photo it later today.
I had an idea if I was to do it again, I would make the laser part tabbed - like the cable chain supports - so you can still bend the part, then trim the tab off with a cutting disk.

See my idea below.

Sean

4953

[Gerald D]

After having used a skate myself, I realised that "back bridge" (the part that Sean shows as tabbed in for cutting out) is not needed for strength. Thus that bridge can be permanently removed, leaving a wide open space for disk changing. However then the disk is even more exposed to the hands. Maybe the "bridge" must be moved further away, leaving a bigger hole, but being protective of the hands?

[MattyZee]

I have one more thing to add. The holes to attach my grinder were a bit different (and i assume there are heaps of variants around the world). Can we remove the sloted holes and just have the round cutout for the grinder head. Maybe then have laser engraved lines so people can drill the holes where they need them.
4954
I had to drill holes in the tiny bit left between the slot and the outer edge which meant the skate need a bit of re-work. It would have been fine if the slots weren't there. I don't think its too much work to expect every to drill their own 4 holes.

[J.R. Hatcher]

Matt this is the original plate you received.

[J.R. Hatcher]

Matt may I suggest downloading the file in post #94 then print it out and see if it would fit your grinder. The original plate did not fit my grinder either but this one does.

[MattyZee]

Opps, yep, was doing it from memory at work. My holes near the edge were closer together which meant the thin section had to be removed. Which caused a few issues when i tightended the screws. I had to put an off cut in there so the screw head was supported on both sides. Will take a photo tonight to better explain.
Still, my comment stays the same. I suggest getting rid of the small holes and just leave the large bore. Use laser engraving to show default holes locations to make it easy for people with the normal hole configuration.

[MattyZee]

Matt may I suggest downloading the file in post #94 then print it out and see if it would fit your grinder. The original plate did not fit my grinder either but this one does.

ok, will do tonight. i'll let you know

[bradm]

However then the disk is even more exposed to the hands. Maybe the "bridge" must be moved further away, leaving a bigger hole, but being protective of the hands?

Is it? I'm visualizing that as all on the underside, and the risk appears to be more at the sides of the disk, assuming you are operating the skate from above. I wouldn't be reaching blindly under there bridge or not.

Even the old bridge wouldn't protect from hands sliding down the handle of the grinder. I think the key here, and a missing point, is someplace to attach handles in the area of the new bearings. In the old design, you could screw them onto the tops of the height adjustment bolts, or (in my case) wear welding gloves and just grab the bolts themshelves. There isn't any nice attachment or grab point anymore.

Actually, on further reflection, maybe the answer is to attach to the handles to the top of an extra long bolt through each of the outer bearing stacks.

[Gerald D]

Brad, the current design has lots of options for attaching any design of handle you may think of, but I reckon a large percentage of guys are not bothering to attach extra handles and that's where the risk of getting the hands to the disk lies. Snag is, the current design requires one to remove a guard from standard grinder, but doesn't offer a way of compensating for it. Imagine the fun a lawyer can have with that . . . . . (hope that my disclaimers (http://www.mechmate.com/useragreement.html) for this website hold!)

JR, I am not happy to move this line upwards - there is every chance that less grinders will fit to the plate:
4956
. . . being located between the two "wings" of the plate, it is a nasty spot for a DIY guy to get in and remove metal. (My own grinders, all 11 of them (3 brands, 7models), would need the plate to be chewed away there).

Matt, I prefer your idea of scribing the lines near the upper thin part, but would like to leave the slots for the lower 2 screws.

[Gerald D]

Brad, maybe your skate version was before I added extra metal & holes for screwing/welding on handles? :

4957

[Gerald D]

The magenta part is what I meant by "moving the bridge" and forming a disk guard of sorts. Leaves a big hole for disk changing:

4958

[Alan_c]

That should make it a lot safer.

For those wanting to attatch a handle, see here (http://www.mechmate.com/forums/showthread.php?p=9551&postcount=92), this gave very good control and kept the hands far enough away from the disk to be safe, but with the addition of Geralds mod above, it would be even better.

[J.R. Hatcher]

This is what they look like cut.

4959 4960 4961

[sailfl]

J.R.

What is with the bicycles?

[Gerald D]

That's a laser company's handouts - looks like JR is getting close to new supplier near him . . . . :)

[J.R. Hatcher]

Is that cool or what. How can they do that?

[sailfl]

J.R,

How about a blow up of the bicycle?

[Gerald D]

Use this (http://upload.wikimedia.org/wikipedia/commons/0/0d/F1_grenade_DoD.jpg) to blow up the bicycle

[jhiggins7]

Gerald: Always the comedian.:) ...but you better not quit your day job.:D

[sailfl]

Gerald,

You need to find another business to start, you have too much time on your hands.!!!!

[Gerald D]

Sorry JR, this thread has drifted a bit off, but you can only blame yourself! :D

[J.R. Hatcher]

Responsibility accepted .... now back to the skate plate.

[chrisd7306]

Hello,
I have been reading all your replies to the interesting topic of the skate design.
I am just up to the stage of building the skate to grind my rails, I have cut them to the correct height (what a horrible job, 3 hours to cut 4 rails, I am glad that part is over!!!!).
I would like to contribute some ideas to the discussion!!

I have tired to incorporate all the ideas so far from Gerard, JR and the rest of the people and build on the existing structure/design philosophy. The design is addressing the issue:-

of safety by adding 2 handles
lowering the skate to the rail to get better and more consistent control
ease of changing the bearing that sites on top of the rail (never like welding in axles!!! sorry JR)
the rotation of the grinding disc (with respect to the rail) to prevent glazing of the disc to give a better cut


I have added a bearing support at each end of the skate which is fixed by 4 csk screws.
This lowers the skate to 1.6 mm above the rail. A 7 mm height boss has been turned on top to accept a handle.
My Hitachi handle has a M10 thread but adjust to suit your handle.
The axle is held in place by 2 x M3 set screws adjusted from the top.
Bearing is 6001 to match the other bearings.
With the handles in this position, it keeps most of the forces low and directly on the top of the rail thus minimizes the twisting action if the handles were positioned off to the side of the skate.

The rotation of the grinding head was an interesting problem. I have split the bottom plate into 2 new plates.
I hope you can see how this will work.
The bottom plate fixes the position of the skate to the rail.
The pivot plate and the existing motor plate are used to rotate the disc 18 deg in either direction with respect to the rail. This 18 deg could be changed easily if needed.
The bottom plate has 8mm diameter pivot stub 6 mm long which the pivot plate rotates on.
The pivot plate has 2 threaded holes with 2 x M8 thread rods which pass through to the bottom plate and to the motor plate.
The angle can be adjusted first, then locked off by 2 nuts on the threaded studs. The forward and back position can be adjusted by the 2 x M3 bolts in the Motor plate and then locked off by another 2 x M8 nuts.

The angle of the grinding head and the forward and back can be adjusted independently or independently locked in position.

I have not done an interference check when I rotate the pivot plate to the max angle but I think the disk opening may have to be changed a bit and the 4 bearing support bolts underneath the skate may have to be changed to studs (maybe).

I hope these ideas might spark some other ideas!

Cheers
Chris

[Alan_c]

Chris

Interesting proposals, question regarding the height of the skate above the rail (given as 1.6mm) Will that still allow enough space underneath to fit in two bearings on a bush without the bearings fouling on the inside corner radius?

18 deg of pivot is way more than you need, 2-3 deg will be more than sufficient, this may be adding complication and extra components where it is not required. I found with the standard skate there was sufficient play in the bolting arrangement to give me enough "twist" on the mounting to grind with minimal glazing.

[Castone]

I dont think that glazing is a problem with the design, as with most types of surfacing the main objective is to keep your grinding stone as flat as possible. Just keeping the skate in motion will prevent glazing of rails.Handles would be a nice option but the skate was designed to make a set of vee rails for a home build with limited tools. I think that the skate fits its purpose. If the skate is changed much more it will take more time to make your skate, than it takes to just grind your rails.

[Alan_c]

Leo

The glazing is not on the rail, but on the grinding disk, after a while it stops "cutting" and just tends to glide over the steel, tilting the skate so the initial grinds are with the leading edge of the disk minimises this. When the profile is almost complete, the grinder is adjusted so the disk is flat on the face for the final polishing

[lumberjack_jeff]

Like most things, the second time around will be easier.

I finished grinding my rails. Here's what I did;
First, I attempted to cut the rails to height with a cutting disk in my grinder. My hand-me-down grinder would not allow the thin disks to cut flat. They had roughly 1/16" of runout at the cutting edge, thus my kerf was 1/8" +. That didn't work.
I looked around for an affordable grinder which would fit the skate. No luck, so I bought a steel cutting circular saw. Once I got the fence adjusted right (the front ever so slightly wider than the rear) they cut the rails nicely and quickly. The first couple of rails have some low spots. I welded up the dips with a small wirefeed welder to bring the overall height to 30mm or so. I was worried that the rails would warp as a result, but this hasn't been a problem.

I then went back to my grinder and surfaced the rails to eliminate the saw marks (and flatten the welds) using a thick flat disk (which did run true on my grinder).

Now they were flat, smooth and the right height.

Then to the skate. I found that if I tweaked the long 5/16" adjustment bolts slightly to assure that the grinding disk contacted the rail only at the circumference of the disk, glazing was minimized. Once it was adjusted properly, I found that there were only two significant frustrations;
a) because two of the holes for bearing axles was so close to the bend, the bearing axles were not exactly parallel, so I could not adjust all the rock out of my skate.
b) the 1/2" height adjusters. I could not find brass or hardened stainless bolts locally, so I used steel. They had a high degree of friction and I found that they would stick to the rail frequently.
http://i3.photobucket.com/albums/y58/lumberjack_jeff/003-2.jpg

From that experience, I think that the bearing idea is a good one. Besides, the bearings come in packs of 10, and only 8 are required to guide the rail.

[J.R. Hatcher]

Now may be a good time to post these. I need to change the cap screws to button heads. It will skew way more than is needed. It is very easy to adjust and fine tune.

[lumberjack_jeff]

Cool! I like it.

Something which would also be cool is to set up the long angle adjustment screws so that they don't bolt through both upper and lower pieces, but bolt through the upper and simply ride on the lower. In this way you could still fine tune the v-angle, but adjust the depth of cut more easily.

[J.R. Hatcher]

Jeff, not sure I'm completely following what your saying but the way I see it, the 2 plates need to be bolted together securely. Thanks

[J.R. Hatcher]

May I make a suggestion. Try removing the extra nut so the bearings riding the sides of the rails are the same height. The way they are offset allows the skate to rock and creates a problem when grinding the opposite side. IMHO

[lumberjack_jeff]

Yes, I think you're absolutely right about the extra spacer... in retrospect it was unnecessary and counterproductive. I had to do a fair amount of searching the forum to find a photo/drawing of how they were supposed to be configured. Unfortunately, what I found first was a concept sketch... that I misinterpreted.

http://www.mechmate.com/forums/attachment.php?attachmentid=501&d=1193289275

The two front bolts on your skate hold the two plates together pretty securely. If the upper skate plate was bent slightly less than 45°, the two back (long) screws would only have to hold the plates apart at the proper angle.

Since your new bearing equipped skate uses the relative position of the two plates to adjust depth of cut (instead of the 1/2" bolts in the V1 skate) it would be nice to not have to loosen the back screws (and possibly lose the 45° relationship each time DOC is adjusted.

BTW, how are the bearing axles secured? Tack welded?

[Lex]

It is looking good JR! I am busy assembling mine. Will post photos soon.

[J.R. Hatcher]

"BTW, how are the bearing axles secured? Tack welded?"
That is correct they will be tack welded right at the end of the axle, on the top of the plate (1st picture). The bottom of the axle will be flush with the bottom of the plate (2nd picture). If anyone needs a special picture just let me know sometime today, it's easy to take right now.

Thanks Johan I'm looking forward to your pictures.

[smreish]

JR,
Once again, elegant solution.
A neat find at the local Lowes. I found in the furniture hardware aisle 5/16" socket head flush (like an elevator bolt) head. Only about 3/16" flat head height.

That shaft...is it an "off the shelf McMaster pin, dowel, shaft, etc....or is it a machined item?

Thanks for your contributions.
Sean

[domino11]

JR,
Are you making another machine? Or maybe you have worn out your old rails on all those boat hulls? :)

[Gerald D]

Sean, some of the fancy headed screws/bolts cannot be fully tightened from driving their heads - they need a nut on the other end and the nut is tightened to develop the full load. The countersunk below is one of the worst:

5285

The head has too much friction inside the cone of the CSK and the allen key/wrench hole is smaller than normal for that thread size.

[Doug_Ford]

"The head has too much friction inside the cone of the CSK..."

That never occurred to me before but it makes sense. An R8 arbor in the head of a vertical mill is basically held in place through friction and it has a similar cone shape.

Man, I've learned a lot on this forum.

[Alan_c]

I used those countersunk cap screws, but machined most of the cone away to produce a very low head fastner - there is not that much stress in this application to worry about the loss of strength.

5288
see how compact the complete assembly is.

[J.R. Hatcher]

Sean, I turned the shaft down from .5" to 12mm + enough for a press fit, it's 1" long and has to be tapped into place. Good idea on the bolt, I'll machine about half the head off a 8mm bolt.

Heath my plans are to build another machine..... when??? don't know exactly. My rails don't show any signs of wear whatsoever.

Alan I also like your solution, good idea.

[smreish]

Alan, thats what the bolts look like.
Gerald...correct as always!
I cant wait for my next machine! It's like an addiction now. :)

[Lex]

Here are pictures of my skate with JR's modifications and other suggestions.

5565
5566

I used M4 screws to keep the bearing shafts in position.

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5568
5569
5570
5571
5572

It might be easier to drill and tap into the bearing shaft as shown in the direction of the red line. The dxf will have to be adjusted to move the raduis away a little bit so that one can drill into a flat surface.
I did not have a M10 tap for the grinder handles, so I tack a M10 Nut in position. It lifts the bottom of the handle up so that it doesn't interfere with the top plate adjustment.
I still need to test it.

[J.R. Hatcher]

Johan I like your guard idea. Will you please send me the drawing of the lower plate, I would like to suggest a small change. Thanks

[Gerald D]

J.R., did you miss this post (http://www.mechmate.com/forums/showthread.php?p=26477&postcount=110)?

[sailfl]

Johan,

That is one neat grinder.

[Gerald D]

Johan is discussing the grinder in his own build thread.

[lumberjack_jeff]

I used those countersunk cap screws, but machined most of the cone away to produce a very low head fastner - there is not that much stress in this application to worry about the loss of strength.

I did something very similar... but lacking ready access to a lathe, I ground off the square shank of a carriage bolt, flattened the domed head a bit and cut a slot for a screwdriver blade.

[J.R. Hatcher]

J.R., did you miss this post (http://www.mechmate.com/forums/showthread.php?p=26477&postcount=110)?

I'm sure I read it .... just forgot whose idea it was :o. So Gerald I like your guard idea, will you please send the dxf I have a suggestion.

[Gerald D]

I didn't keep that drawing, it was just a quick rough idea that can be refined. Maybe the guard can even come from the other plate . . . . .

[J.R. Hatcher]

Thanks Gerald. Johan if you have the drawing .......................

[Lex]

I will post the drawing some time today.
Gerald, do you suggest I post all my skate developments here instead of my build thread?

[Gerald D]

Johan, the skate stuff would go better in this thread.

[Lex]

JR, the top plate should still be the same.
5586
5587

[J.R. Hatcher]

Johan what type files are these .... dxf?
Thank you

[Gerald D]

Yes, they are .dxf's. Just change the .txt to .dxf when you save the file.

[Gerald D]

Have now added .dxf files to the types that this forum can load.

[J.R. Hatcher]

A new little mod to the bottom plate.

[Gerald D]

I am thinking that the guard needs to be incorporated in the other plate, for the times when only that plate is used to slice the rail height down.

[Lex]

5672

5673

It will never win any beauty contests, but it works!
JR, thank you for the great idea! :cool:
I added the wheel adjustment as shown.I get a very fine adjustment now on the wheels. The design just need to be tweaked so that those small screws are not so close together. The nuts next to the bearings are rubbing a little bit against the seals.
The bearing wheels runs smooth across the rails. Just like Jude's hovercraft from Sidney!:D
I still have one rail to do. The glazing of the disk was a problem even when I adjust the disk down at one end. I think it is just one of those things that one has except. I used two disk per rail so far!

[Gerald D]

Is it necessary to (fine)adjust both ends of the skate?

[Lex]

Maybe not Gerald. One side might do it.

[Gerald D]

I have an awful way of "dressing" a grind wheel and I am hesitant to mention it because it just seems so unsafe and unheard of. I run a similar grinder against it - 2 disks spinning against each other. Not recommending it at all - the noise, dust, vibration doesn't look healthy.

[Lex]

Interesting. That is why the South Africans are such good inventors. We will try anything to descover something new. Even bend or break a few rules in the proses!:D

[smreish]

jules vern here I come!

[Lex]

Ja Sean. Africa is not for sisies!:D

[Doug_Ford]

That looks great Johan. And it's leaving a mirror finish on the rail. Beautiful.

[Lex]

Thanks Doug. I must finish the last rail tommorow.

[Atifeh]

Glazing problem occured to me after about 600mm of grinding. I thought it might be because of the quality of the grinding disks that I use. I came around with this solution which works fine for me: sanding disks, grit 36 backed by a solid new grinding disk (disk rubber backings were quite errative and dangerous). Now I can bevel both sides of a rail with one sanding disk per about 1500-2000 mm of rail before it glazes or wears off. The surface quality is acceptable. I also tried to improve the surface finish with 80 grit sanding disk, the surface finish was remarkable, but needs extra work which I believe is redundant. The noise level is much less than grinding disks. Metal removal is good. I set for approximatey 0.5 to 1 mm per pass with my 850W Chinese grinder. The less the feed, the more the disks last.

[Doug_Ford]

That looks great Nader. I used a whetstone to polish mine a little after I finished grinding.

[javeria]

wow - Nader - where is your build thread???

[Lex]

That's good idea Nader. I will remember that if I have to build another BBB.:D

[Atifeh]

Thanks for the kind words. To tell you the truth, due to my limitations I had to redesign numerous parts so these machines are actually a mutant between MechMate, ShopBot and my own design, needless to say that I owe its design to Gerald's generous sharing of his ideas, and the concepts and discussions over here from you all.
Although I have compiled a day to day log of my activities with step by step pictures while building these machines, I thought it would be rude and inappropriate to introduce a new design in MechMate forum, which might bring distraction or confusion from Gerald's original idea and efforts, to those who are building or intend to build the MechMate.

[bfauska]

Nader,
Now you really have to show us your build, that's too intriguing to let it go. Even if it's in a different forum somewhere you should post a link, or I bet Gerald would be OK with you showing a "Mutant" machine, maybe if you call it a "Hybrid" it would be more enticing.

[MetalHead]

This new skate - was it decided this was a better design? I am getting the Laser Parts kit together and this new file is not part of the Profiles DXF list. That list still has the standard skate.

[domino11]

Mike,
As far as I know this new skate design is not part of the official mechmate cut list release. Gerald may decide to include it at a later time, but I am guessing. This was just some of the guys modifying what was available to their liking. :)

[Gerald D]

I didn't think there was an obvious enough improvement to warrant a special drawing release. I will probably change the drawings one day, but more for the reason of incorporating a disc guard. Before I change the drawing, I will warn the guys holding stocks of lazered kits.

[jimj]

Are the cut and stamped parts of this skate available for purchase from someone?

[MetalHead]

sent you a PM

[hutchcj]

From post #156 of JR's new design. The DXF seems to be in inches. So if you're going to have it laser cut this may need to be scalled to mm.
Otherwise, it's looking great.

[hutchcj]

The Makita grinders seem to have a slightly different hole pattern. For some reason the bolt are not located at 45 degrees. I've measured up a Makita 9556 and come up with the drawing below. On my skate I welded up the original slots, re drilled and cut back some of the skate. (Original in orange)
If anyone else has a Makita Grinder, can you check if it fits the different models.

[Drew]

Does anyone have updated plans I can have to make the best version of the skate so far

[MetalHead]

Sent you a PM

[cncmike]

Hello everyone, I'm looking for one of the new skate assembles. Would someone have one they may want to sell. Please let me know.

Thanks
Mike

[anajanxxx]

thanks for idea
anajanxxx

[jimj]

Is anyone selling pre-cut/bent plates for these?

[MetalHead]

Yes - I do.

http://www.cvsupply.com/servlet/the-MechMate/Categories

[shipbldr]

Hello Mike,

I just recieved my skate kit (THANK YOU!

Can you tell me which grinder the holes are setup for? Is it the Bosch 1375A?

I have to buy a grinder for this anyway... so I figure I might as well buy the grinder you designed the skate for.

Thank you :)

Charles

[domino11]

Not sure about the bosch, but I have a dewalt that fit the hole pattern. Not sure of the model number but could get it for you tonight if need be. I just brought my plate to the store and checked it before I bought it. :)

[shipbldr]

Not sure about the bosch, but I have a dewalt that fit the hole pattern. Not sure of the model number but could get it for you tonight if need be. I just brought my plate to the store and checked it before I bought it. :)

Heath,

That would be a big help! Much appreciated!!

[KenC]

I have to modify the mounting holes to fit my Skill. What I did was enlarge the slots with a grinder fitted with the 1mm cutting disc.

[shipbldr]

I think I found a Ryobi grinder at HD last night that is a drop in fit.

I have to buy some longer mounting screws... but other tahn that it looks "all go"

If it fits without modification I will post it tonight. The only downside is that it is a 4.5amp grinder and for this kind of work I would really rather see a 7 amp grinder doing the work.

A BIG THANK YOU to everyone whose ideas and work made this skate possible and to Mike who took the timre to produce it. Trying to design and build one of these skates would have been more trouble that it was worth for a single project. The skate turns this into a cool learning exercise!

[smreish]

The Ryobi at HD will fit. You will need to purchase longer metric fasteners and little nylon spacers to make it work. The head on the Ryobi is slightly tapered and the 4 spacers make it seat properly to the skate.

The spacers need to be about 3/16 or 1/4 long plus about a 3/4"-1" long fasteners, I can't remember the actual length.

[domino11]

Darn, too late. My grinder was the Dewalt DW818 if it helps anyone else out. :)

[Tom Ayres]

Does one of the HF grinders work? Has anyone used them? I have the makita stated above and didn't want to modify the skate unless I have to, easier to get a cheapo HF while I'm there.

[domino11]

Take your plate with you. Thats what I did when I bought the dewalt. :)

[Tom Ayres]

I thought about that after I posted, thanks Heath:o

[bradm]

Tom, IIRC one of the HF grinders did work, but it was underpowered for the job. After I burned it up, I switched to a Milwaukee (for more than twice the price) that not only finished the job, but is still going strong to this day. If I had to do it again, I wouldn't bother with the HF; the performance of the grinder maps directly to how much time you have to spend.

[domino11]

The old pay once for quality tools, or keep paying with cheap ones. :)

[Tom Ayres]

I have a Makita I've been using for years, it has enough power to work. The skate will take a little modification but no big deal.

[LizardKing]

Ok, have the bent parts for the grinding fixture but can't find a BOM for it.
What size adjusters, bolts, and nuts are needed?
The bom.xls @ http://www.dmoore.com/mechmate/bom.xls is gone...