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View Full Version : Handmade V-Rails - "JR Skate" has 4.5" grinder riding the rail


J.R. Hatcher
Tue 17 April 2007, 11:23
(This post was made in this thread (http://www.mechmate.com/forums/showthread.php?p=370&postcount=20) before - it has deserved its own separate thread)


Gerald, it's amazing how minds on opposite sides of the world can think in harmony. How do i upload pictures to a post?

J.R. Hatcher
Tue 17 April 2007, 12:03
Gerald while you were brainstorming this passed week, i was too, here is what i came up with. I will try to upload some pics.
http://www.mechmate.com/Forum/messages/11/6273.jpg
http://www.mechmate.com/Forum/messages/11/6274.jpg
http://www.mechmate.com/Forum/messages/11/6275.jpg
http://www.mechmate.com/Forum/messages/11/6276.jpg

Report of the first test run (http://www.mechmate.com/forums/showthread.php?p=3685&postcount=17)

Gerald_D
Tue 17 April 2007, 12:08
That's a beauty! Applause!

Arthur Ransom
Tue 17 April 2007, 12:55
JR when I get ready to do my rails how about renting me the grinder for a week. You could start your own rental business!

Marc Shlaes
Tue 17 April 2007, 12:59
Tremendous! I too would like to rent it!!! That is certainly better than anything I was dreaming about.

Greg J
Tue 17 April 2007, 16:06
WOW!! There is allot of talent here.

Very nice work.

J.R. Hatcher
Mon 11 June 2007, 14:25
As the work continues! It took about 9 hours to cut, grind, and bevel the rails (2 pcs 12' and 2 pcs 8' rough lengths) and they came out even better than I expected (Gerald, the skateboard works great). The masking tape makes layout a lot easier, and if you mess up it's easy to remove and start over.

Marc Shlaes
Mon 11 June 2007, 15:56
J.R.,

When you cut the rails, did you slide the rail or the cutter? Based on your setup, I'm guessing you slid the cutter.

Also, the angle grinder you made is absolutely beautiful. Seriously, are you interested in renting it out????

All the best,

Marc

J.R. Hatcher
Mon 11 June 2007, 17:50
Marc, you are right, it's the cutter that moves, the rail is C clamped to the main beam (makes a great work surface). I cut my main beam (7" channel) 1st, should have left it 20' long, would have worked a lot better as a work surface. The little grinder is hard to control when you first start on a rail, it's because the depth rollers do not touch until it's almost completely finished. I need to address this problem before anyone else uses it. Maybe it will be more user friendly by the time you start your MechMate.

Gerald D
Mon 11 June 2007, 23:08
Great stuff J.R.!

How much did you lose at the tip of each rail because of the skateboard's length? It's very important for folk to know that they must not cut the rails to exact length before shaping the V.

Like how you marked out the holes on masking tape. :)

J.R. Hatcher
Tue 12 June 2007, 04:53
In the US stock steel comes 20 feet long(+ around 2" extra). My MechMate cut dimensions are 52" X 100" (our mdf comes 49" X 97", I've been building custom cabinets since mid 1970, still don't know why 49", 97"). I cut the rough length of the rails X = 12 feet and Y = 8 feet + or - a little (that's about 12" extra on each end. My skateboard is 16" long, by the time it hit the stop I only had about 2" in the clear, passed the "finished end".

tpworks
Thu 21 June 2007, 20:07
JR,
Do you have a dxf of the skate board plate?

Tom

J.R. Hatcher
Thu 21 June 2007, 21:08
Tom I'm sorry to say I don't. It's right from the head. It would have taken me longer to draw it than to make it.:D J.R.

Greg J
Mon 20 August 2007, 20:20
J.R.

I'm building your "skate" tool to grind the rails. Gerald's way works, but I want to try your method. I think the time invested will be well worth it.

I have a few questions concerning the roller that rides on the vertical 1 inch leg of the rail. I've searched McMaster high and low for rollers close to yours. Where did you get yours? Was the shaft a press fit on the rollers? The cheapest roller I found had a 1/16 inch clearance between the bore and shaft (if I used a 1/4 inch Dia. shaft). Or, is it a non-issue.

The guide rollers are not a problem.

I'm putting my design and parts list on AutoCAD and will post a PDF file if anyone is interested.

Greg

Les Filip
Mon 20 August 2007, 23:23
I am sure I am not the only one who would appreciate the plans for the grinding skate.

Take Care,
Les

J.R. Hatcher
Tue 21 August 2007, 06:32
Greg my bearings were surplus I bought them 15 to 20 years ago for $.25 each from a tractor store. They have a 3/4" bore and yes they are a press fit. I knurled a 3/4" rod to increase it's diameter a little.
The 1" leg has to be 1 1/8". I will double check this.
The stud for the rollers that ride the sides need to be very beefy. It has an ecentric hole for the adjustment bolt.
If you need closeup pictures of anything let me know.

Greg J
Tue 21 August 2007, 07:15
Thanks J.R.

Have to run, darn day job getting in the way again. :)

I'll work on it tonight.

Greg

tpworks
Tue 21 August 2007, 10:10
Greg,
Have a look here, http://www.vxb.com/ I have purchased from here before for my mini mill spindle bearings and thought they were reasonably priced.

Tom

Greg J
Tue 21 August 2007, 12:52
Tom,

Thanks. That's the site I was looking for. I like McMaster allot for service, but they are high priced. If I was to use McMaster rollers, my "J.R. skate" would soon be approaching the "snap-on" league.

Greg

Greg J
Tue 21 August 2007, 13:22
J.R.

According to drawing M1 10 110 Rev A - the X rail is 2.5 inch by 1.0 inch for us on this side of the Atlantic.

Greg

J.R. Hatcher
Tue 21 August 2007, 13:31
that's correct but to use the same skateboard as mine you will need to increase that to 1 1/8". The bearings bottom out on the inside corner.

Greg J
Tue 21 August 2007, 14:00
J.R.,

I'm going to keep it at 1 inch. Using the web site that Tom supplied, there are any width one could want.

I wanted to ask you, does your skate stay vertical or does it rock back and forth, perpendicular to the X rail when grinding? It looked like you had a very nice 45 degree edge on your rail.

Greg

tpworks
Tue 21 August 2007, 18:27
Greg,

I'm not sure but it looks like J.R. might have doubled up the side bearings. I would think that the wider the bearing surface the more ridgid it would be (less chance for a rocking action), at least that is what I am seeing.

Tom

J.R. Hatcher
Tue 21 August 2007, 18:51
Tom you hit the nail on the head. It doesn't rock any when the side bearings are adjusted tight against the angle. I did use 2 bearings per stud, so about 1" (2-1/2" bearings) X 4 (studs) of metal to metal. If yours rocks use Gerald's suggestion and put an outrigger.

Greg J
Tue 21 August 2007, 21:24
In my paper design, I'm using 7/16 inch wide bearings. When you look at a cross section of the rail (2-1/2 inch x 1 inch angle) there isn't much surface area. It obviously works since J.R. has produced very nice rails (J.R. did add 1/8 inch, but I can't believe that an 1/8 inch adds that much surface). I did off set the center of the 3/4 inch diameter shaft for the bearings. It should be a tight fit.

Let me know if i'm missing something. I have to order parts (haven't done so yet), so when I get my parts, we'll have another prototype.

283

Gerald D
Wed 22 August 2007, 00:05
The "outrigger" I suggested before is the blue bearing:

284

Remember to think how you are going to hold/clamp the rail (if at all) before you run an "outrigger" wheel

Allegheny
Wed 22 August 2007, 04:50
JR,

Using an eccentrically drilled 3/4" rod for the bearings is a clever way to allow for tightening the jig onto the angle via cam action. I have two questions, however.

First, how do you intend to rotate the cams to equal pressure? Also, would it not be easier to have both bearings on one side of the angle use center bored rod and have cams on the other? This would make adjusting the entire skate, and the surface of the grinding wheel, to be parallel to the rail much easier.

Secondly, how do you intend to keep the bearings from riding up the rod toward the carrier plate as the skate is pressed down as it is moved along the rail (perhaps a second bearing stacked on top to fill the entire space under the carrier plate - this would have the added advantage of offering more support during the early grinding when the rail is square)? There is no washer/retainer of any type in the drawing. It would be possible to turn a taper on the rod (say 0.5-1^o) thereby creating a press fit, but this can be tricky as too much pressure can deform the bearing and cause it to malfunction.

Brian

Greg J
Wed 22 August 2007, 06:07
I think I'll make the skate as is (aka - J.R.'s skate) and post results.

Its amazing how some people can design and fabricate in therir head. Not I.

On another note - My C-channels arrived yesterday :). Geeez, J.R. that C7x14.75 is 300 lbs (136 KG) by itself. You moved the partial table outside to the paint booth by yourself? I think I'll start calling you SIR (as in yes sir!)

Greg

J.R. Hatcher
Wed 22 August 2007, 06:27
First; Brian based on using the tool, having equal pressure does not seem to be an issue. Having all bearings adjustable makes setup a little easier, once you get it adjusted you leave one set alone as if they are center bored. Also being parallel doesn't seem to be important as long as you have enough extra length to get the wheel completely off the good piece.
Second; The bearings are pressed on the 3/4" rod(read earily post in this thread to see how this was done), they don't move. Remember the most important pass is the last one, anything extra should be done here.

J.R. Hatcher
Wed 22 August 2007, 06:33
Greg since I moved those sides by myself my wife said she thinks my voice is a little higher???:eek:

Greg J
Sun 09 September 2007, 11:00
Here's my version of J.R.'s Skate (rail edge grinder).

I used 14 gage for the base plate for two reasons. First, it is easy to work with. There are slotted holes, and I don't have an end mill to machine these features. Instead I used a jig saw with a metal cutting blade. Second, 14 gage plate is what I had laying around the shop.

Because I used the 14 gage, there was allot of flexing. So I added 1/4 inch thick bars for stiffeners. These stiffeners were left overs from cutting the 2-1/2 inch leg of the angle down to 1 inch. Waste not, want not.

The bearings were stock from www.vxb.com. The other parts (handle, nuts, bolts, etc) were McMaster Carr.

I tried to fabricate this tool, so anyone without lathes, end mills, etc. could make one. The cost is resonable also.

330

331

332

Gerald D
Sun 09 September 2007, 11:29
Ah! The proof of the pudding shall be in the eating! :)
(Looks good, but let's see if it works.)

If I were making the "JR skate", I would cut off the ends so the tips of the rails would be visible all the way to the rollers. Also, I would trust the handle screwholes in the body of the grinder to actually hold the grinder at the correct angle - can you tighten those hard into the (plastic?) body? I think I would shorten everything as far as possible so as to lose less unground rail length at the ends.

Greg J
Sun 09 September 2007, 11:52
Yes, it does work fine. I'll post some pic's of the rail when I get time. (My weekend job is irrigating our alfalfa crop, geeez, I don't have enough to do :))

It rides the rail very nice and I don't think one needs to cut the ends off to the rollers. The plastic body of the grinder has brass inserts for the handles so it holds the grinding angle OK (not saying it couldn't be better )

Yes, there is some waste on the ends of the angle, approx 10 inches [254 mm]. I have not cut my 20 foot [6 m] angles yet. The waste will equate to about 4 USD [2 USD per foot for 2x2x1/4 inch angle).

Greg

J.R. Hatcher
Sun 09 September 2007, 11:59
It looks good, I hope it works as good as mine does. S/N 002 has been issued. Who wants S/N 003?

Greg J
Sun 09 September 2007, 13:59
Not so fast with the S/N. Gerald has a good point. When I post pic's of a good rail, then I'll accept 002.

It may still require some mods / refinements. Something is not ridged. I don't have a consistent surface / edge on the 45 degrees.

Greg J
Sun 09 September 2007, 16:24
Back to the drawing board. That Dewalt grinder with the plastic housing does flex at the connection points when grinding. How in the *%$# can Gerald see that and he's half a world away and I couldn't.

Learn and move on. I have a Ryobi grinder like the one used in the trash can example of the rail grinder. Its a newer model and the housing is different. I'll try something new with the other grinder or buy another angle grinder that will work.

Lesson learned - make sure your grinder has a metal housing for a solid connection. Time for a beer and a ball game.

Greg

gmessler
Sun 09 September 2007, 19:52
Hi Greg,

Great job on the skateboard!!:) What model number bearings did you use?

I spent a lot of time looking for a good grinder to use for my skateboard and have found that most of them have either plastic housings or the handles are no longer perpendicular to the body of the grinder they are angled back. I had previously purchased this one from Harbor Freight but was unsure if I could make the front attach the way Gerald did on his. With your design I don't think it would be and issue.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=31309


Hope this helps.

Greg M

Greg J
Sun 09 September 2007, 20:13
Thanks Greg,

If I can't find a suitable grinder locally (slim to none), I'll order tomorrow night (If I do one more overnight shipping, my wife is gonna shoot me).

The bearings/rollers are P/N - R12ZZ (3/4 inch ID x 1-5/8 inch OD x 7/16 inch wd).

Attached is a partial parts list. Note that I used low head socket cap screws. Not allot of space. I would also go to a larger three-arm knob. The list is not complete, and I'll finish it some day.

Greg

333

Gerald D
Sun 09 September 2007, 21:05
If you take a bit of flat bar, say 1" x 1/8" x 4" long, bend the last 1" at 45 degrees, erect that verically under the grinder, then hoseclamp the body of the grinder to that bent 45 deg. . . . . . ? That should attach the grinder at a 3rd point and steady it out.

Greg J
Sun 09 September 2007, 21:18
Hmmm ... always the simple solution ... :)

Grinders are so inexpensive these days, I'll look in town tomorrow to see whats available, ....

P.S. - One more "move" on the irrigating tonight and up at 0500 for the last "move" and off to the day job. I must enjoy this :rolleyes:

Gerald D
Sun 09 September 2007, 23:43
Hey, I had to look up alfalfa to figure out what it is. Turned out to be the stuff we call lucerne and of course there is a lot of it here too. Do you feed it to your own animals or do you sell it?

Greg J
Mon 10 September 2007, 06:03
Good Morning Gerald (as least here),

Both. There are allot of dairies so we sell mostly to them. Our friend has two dairies and 10,000 head of cows.

Oops, getting off subject (sorry). I'll look for an inexpensive angle grinder today or maybe get a flash of genius and figure out a way to use either of the two that I already own.

Gerald D
Mon 10 September 2007, 06:11
There is a connection between cows, dairies and CNC routers, so by luck we have hit on something that could be very useful to you.........

Holding boards down to CNC tables and auto-milking of cows use vacuum pumps, big vacuum pumps. You might starting lining up an old vacuum pump to fall in your direction . . . . . :)

Greg J
Mon 10 September 2007, 07:24
I sure like the way think. I wouldn't have thought of that in a million years.

You also wouldn't believe what people throw away. Rebuilding pumps is right up my alley. I will keep my eyes open for an old vacuum pump.

Thanks and have a good day/evening.
Greg

Greg J
Mon 10 September 2007, 12:49
Things are looking up. I found an angle grinder with a good metal frame that can be modified. Locally!!! and for 21 USD :D

Will start the mods tonight. I wonder if there is a self help group for the MechMate/CNC addiction. :)

Alan_c
Mon 10 September 2007, 14:32
Good going Greg... I am still working on my design, that problem with holding the angle of the grinder is also concerning me but some lateral thinking will get it sorted.;)

the best support you are going to get is right here amongst fellow addicts :D

J.R. Hatcher
Wed 12 September 2007, 06:26
Greg my main plate is 1/4". If I have any flex in the bearings that ride the sides of the angle I can't tell it. Because your main plate is only a little over 1/16" it seems to me there would be a problem with this type of flexing. I would suggest you check this on a scrap piece of 1/4" material. If these bearings spread any it will cause a problem in the finished rail. Just a thought.

Greg J
Wed 12 September 2007, 20:24
Thanks J.R.

I don't think its a problem, but, if I've learned nothing else, I have learned that "The proof is in the pudding".

I will take your suggestion and verify. I've got everything needed to modify the skate, but time. Hopefully I'll have some "leisure" time this weekend.

Greg

Hugo Carradini
Fri 14 September 2007, 18:22
J.R Nice peace of art. :)Because you are capable of doing such a beauty, I want to ask you if you have seen working . . . . . . . . .

This moved to the thread where milling (not grinding) of the rails is being discussed. link (http://www.mechmate.com/forums/showthread.php?p=4854)

J.R. Hatcher
Fri 14 September 2007, 19:32
Hugo I have never seen either of these tools. I think the smaller one could work if some modifications were done. As it is right now I agree with you, it would not cut the inside bevel. When do you plan to start your venture?

bbreaker
Sat 15 September 2007, 00:46
hugo, if you want i've got this link.

http://www.gullco.com/more_kbm.html

Michel

J.R. Hatcher
Sat 15 September 2007, 06:38
Go to my thread and you will see how I used the "skate" to grind my rails. However afterwards I realized how simple it would have been to have built the MechMate base then attached the rails as if they were already ground. At this point you will need to leave them extra long. Using the skate you will grind the rails on the machine then remove the extra length. If you choose this way contact me first there are some minor details. If anyone wants close up pictures let me know. J.R. ps I realized I could have the bottom plate laser cut if anyone is interested, possibly even a kit?

bbreaker
Sat 15 September 2007, 07:08
whooo J.R a kit !!!!!

For me, i jusr need the size of the board, i do the rest, but i've got an idear last night, why not twice the bearings on the long side, you can start right the first time of grind.

Michel

J.R. Hatcher
Sat 15 September 2007, 07:48
Mickey at first glance I said that is a great idea BUT then I realized the skate has to be turned around to grind the other side:(.
My base is 1/4" (6mm) X 4" (102mm) X 16" (406mm).
One of the reasons I chose the Hitachi was because it has a 7 amp motor.

Gerald D
Sat 15 September 2007, 08:44
. . . . I realized how simple it would have been to have built the MechMate base then attached the rails as if they were already ground. At this point you will need to leave them extra long. Using the skate you will grind the rails on the machine then remove the extra length. . . . .

All along the plans said to attach and align the rails with extra length. :)

(I envisaged the "outrigger" running on the opposite side rail . . . . )

J.R. Hatcher
Sat 15 September 2007, 09:18
Talking about stability. I see Gerald's outrigger being a welded 4" length of 1/2" pipe (w/ a thumb screw mid way[nut welded to pipe]) across the skate plate. Then a 1/2" piece of cold roll (w/ a bearing attached to the end) thru that to the other side. I wish I could draw.

Gerald D
Sat 15 September 2007, 10:29
JR, now I've got you thinking. :):)

1/2" cold roll to the other side, which is 7 ft away on our x-axis, is a bit light. . . . . . don't rush into this one . . . . . .

My thoughts on "assemble with extra-length" rails have many origins. From the times with our ShopBot and its "too thin" rails, I have been thinking of a "rail-rider" to dress those rails but the rails had no "extra-length". So, I thought one could lay a temporary rail near the original rail and use that to ride on accurately. Maybe an alu extrusion? But the big idea was to have a piece of 30mm [1.25"] cold-roll (there is a "precision" version) as the temp rail. This "rod" supported in adjustable "V-blocks" about 300mm [12"] apart. One would adjust the V-blocks with the help of a dial gauge and the known sag of this rod under its own weight, and turn it under the dial gauges to find its last errors. . . . . . .
For the first rail, one would use the aligned cold-roll rod to give line and height to the real rail being made, while the outrigger which stabilises the twist of the "rail-rider" could happily run on an un-ground rail on the far side. However, as the grinding gets better and better, the outrigger also forces the "parallel", or distance, between the rails. . . . .
These were all schemes which I thought would never be accepted by the MechMate builders because they sound so exotic. Then a bloke called JR Hatcher comes along and shows a "skate" like the darn "rail-rider" that had kept me awake before. I think; "Nice, but everyone else is going to find that too exotic...." However, most think it is great and a couple are being built. Shows how I just cannot predict what the folk here will think is easy or difficult! :):)

Gerald D
Sat 15 September 2007, 10:50
With JR's permission, I would like to use his ideas and do drawings for a "skate" as part of the total drawing package. A lot of the parts could be laser cut. Only snag is to do it for a grinder that is available across the world. Is the Bosch brand available everywhere? Or Metabo, Makita. These big names are easily available here.

Can guys from around the world please jump into this thread and tell us which grinders are easy to get in their countries?

J.R. Hatcher
Sat 15 September 2007, 11:44
Gerald you are more than welcome to use or adapt any of my ideas posted to this forum. J.R.

J.R. Hatcher
Sat 15 September 2007, 11:52
You might want to leave off the entire adjustment thing across the base. Maybe have it slotted but do away with the threaded rods, handles and the angle hanging off the back. It sure did look good it just didn't work very well. The skate exceded my expectations but the adjustments leave somthing to be desired. I have an idea that would raise and lower those top bearings (cam action) to do the same thing with much more accuracy. Off to the shop.

Gerald D
Sat 15 September 2007, 13:23
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 . . . .

bbreaker
Sat 15 September 2007, 13:39
a picture is more explicit. It's not very important upgrade but i think is a good idear.

356

thanks J.R. for your information and your pictures.

Greg J
Sat 15 September 2007, 17:51
Gerald,

I've done allot of preliminary work in AutoCAD. Let me know if you want any of those files.

I'm currently waiting on screws to finish my skate. So, today, I'm working on the X-beams and welding to the table.

Greg

tpworks
Sat 15 September 2007, 23:12
JR, now I've got you thinking. :):)

1/2" cold roll to the other side, which is 7 ft away on our x-axis, is a bit light. . . . . . don't rush into this one . . . . . .


Gerald,
I think that JR was thinking of something a little different from what you are, 4" long vertical. Here is a rough sketch, correct me if I'm wrong JR.

J.R. Hatcher
Sun 16 September 2007, 03:39
Tom the pipe w/ the screw and nut is right but the orientation is horizontal like Gerald was saying.
As I have stated before, since the side bearings are cam design they can be tightened to the point you can't move the skate along the rail because of friction.
My personal belief is an outrigger is not needed.
May I suggest designing the tool without one and adding one later if needed.

J.R. Hatcher
Sun 16 September 2007, 06:23
This is what I came up with for the heigth adjustment. I'll follow up with a picture of it on the tool when the paint dries.
For reference, the bearing OD is 1 5/16", ID is 3/4", turned down stud is 9/16", rod is 1/4", Cam is 1/8" off center. Adjustment capability is 1/4".

Doug_Ford
Sun 16 September 2007, 10:53
Gerald,

I easily found all of the 110V grinders you listed except the 1810PSD and it may be out there somewhere.

Doug

J.R. Hatcher
Sun 16 September 2007, 12:49
This is it on the tool.

Gerald D
Thu 27 September 2007, 12:43
Doug is the only one that answered when I posted the following before:

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 . . . .
Would it help if the laser-cutting kit included parts that fitted to a Bosch grinder as above?

Hugo Carradini
Thu 27 September 2007, 14:43
J.R I will be very interested in buying one of those tools (the set would be great) you are making as soon you confirm it is trust able for the job. They have a very professional look.

Hugo Carradini
Thu 27 September 2007, 14:44
Gerald I will check as soon as possible.

javeria
Mon 01 October 2007, 17:36
GWS 6-100 - MINI ANGLE GRINDER
Part No. : 0 601 375 060
Grinding Disc Dia :100 mm
Power Input : 670 W
No-load Speed : 11000 rpm
Spindle Thread : M 10
Weight : 1.4 Kg

GWS 10-125 C - MINI ANGLE GRINDER
Part No. 0 601 702 755
Grinding Disc Dia. : 125 mm
Power Input : 1020 W
No-load Speed : 11000 rpm
Spindle Thread : M 14
Weight : 1.6 Kg

GWS 850 CE - MINI ANGLE GRINDER
Part No. 0 601 803 574
Grinding Disc Dia. : 125 mm
Power Input : 850 W
No-load Speed : 11000 rpm
Spindle Thread : M 14
Weight : 1.5 Kg

GWS 11-125 CIE - MINI ANGLE GRINDER
Part No. 0 601 823 200
Grinding Disc Dia. : 125 mm
Power Input : 1100 W
No-load Speed : 2800-11000 rpm
Spindle Thread : M 14
Weight : 2 Kg

GWS 14-125 CI - MINI ANGLE GRINDER
Part No. 0 601 824 200
Grinding Disc Dia. : 125 mm
Power Input : 1400 W
No Load Speed : 11000 rpm
Spindle Thread : M 14
Weight : 1.8 Kg

A laser cut kit would definitely help!

These are the available Bosch angle grinders in India.

RGDS
Irfan

driller
Mon 01 October 2007, 18:11
Hi all,

this is my first post here.

I have been making CNC machines for a number of years and probably spend more time thinking HOW to do a thing than actually doing it.

In driving out today to get some metal for a project, I was thinking about the skate and I have a suggestion that might help a bit.

First bring the rollers in closer to the grinder, the handles can go outboard. that will increase how much of the rail gets ground.

second, make the sled longer and add another set past the end. this way, the grinder can go all the way to the end, or past.

of course this means a second set of top rollers.

As for the top rollers, using 4 .. stay with me... it's my first design and all in my head at this point...

using two on each side, the outboard ones would be set to the finish height, the inboard ones being adjustable so as to allow the grinder to take off layers until it reaches the final depth. the adjustable ones would need to have a fixed minimum setting.

The other idea was to mount the grinder on a sub-sled that would feed in until the desired depth was cut.

Anyway, there are a couple ideas to kick around.

Dave

driller
Mon 01 October 2007, 18:55
here is a drawing

Gerald D
Mon 01 October 2007, 23:46
I think a very basic parameter to have available for a skate design, is the fillet radius inside the corner of your angle iron. If your angle iron producer puts a big radius in there then you will have a "wobble" problem because the side bearings will have too little flat surface to run on.

Therefore, let's establish this basic parameter first. . . . . .

Our mills out here put anything from a 6mm to 9mm radius in there, leaving a flat vertical surface of 7 to 10mm. The 7 is too small - the 10 might do.

Maybe it is time to modify the finished rail dimensions on the M1 10 110 drawing to make it more friendly for a JR Skate? Increase the 24mm [1"] to 30mm [1.25"]? . . . . . This will involve quite a few lasered drawing changes because the stepper motors will have to reach lower down . . . . . . .

441

Marc Shlaes
Tue 02 October 2007, 06:09
J.R.'s rails ended up at 1.125 (1-1/8") in order to accomodate exactly the problem you described. I don't believe that, at that height, he ran into too many problems with the lasered metal. I know that his stops should have been a little higher. He didn't think of the rail height difference when he made them. I know he will be back in a couple of days and I am sure that he would love to jump into this discussion.

It does sound like 1.25 would alleviate any issues.

Greg J
Tue 02 October 2007, 06:30
Haven't had much time lately to work on the "skate", but here's what I've learned.

The 1.00 inch (25.4 mm) height of the rail should not be a problem. The first pass at making an edge on my "test rail" went good. Nice 45 degree surface, etc. When I went to grinding on the second surface (other side), it didn't produce the same nice 45 degree surface. I think my side rollers may have loosen. I didn't want to take the chance and get half way through a rail and adjust a side roller. So, I'm adding Gerald's "outriggers" to the skate.

I think adding outriggers is much simpler than re-doing the rail design and drawings, etc.

I'll have allot more time and be back to work on the skate and rail in a couple of weeks. Let me get caught up on all my other "fun stuff" and I'll be able to post pictures.

Greg

smreish
Sun 21 October 2007, 12:22
MM fans & JR.
Well, after some playing around, I think I have come up with a fairly unique workaround for the skate board vertical adjustment issue I have been experience in testing. The issue was the eccentric cams for the vertical (depth of grind) was changing on me. SO, I quickly drafted the following which I plan on testing later in the week for repeatable performance. The best part of the adjuster is that it does so equally. Let me know if I am crazy or not....sometime I get to involved in the engineering and loose all my common sense. Sean

Gerald D
Sun 21 October 2007, 13:11
That won't necessarily do it equally - the skate will be free to rock.

smreish
Sun 21 October 2007, 13:43
You think so? The only thing I have changed is the vertical cam to a divergent bell crank for vertical adjustment on the outboard wheels. The lateral rollers and cam adjusters are still intact. Maybe I am missing something. Sean

driller
Sun 21 October 2007, 14:20
I see a couple of things.

#1 is that the guide wheels are pretty far away from each other as well as the wheel. that means it will not get as close to the end of the rail as it could.

#2 the height adjust mechanism does not prevent one side from going high while the others goes low. it might offer an easy adjustment method, but I don't see how it prevents the transference of hieght from one side to the other.

Of course I could be missing something ???

Dave

Doug_Ford
Sun 21 October 2007, 18:31
Sean,

I agree with Gerald and Dave. It is free to rock. If you were having trouble with the eccentric changing on you, why don't you just add a thumb screw to lock it in place once the correct height/depth is set?

smreish
Sun 21 October 2007, 19:08
Yep. you guys are right....I hadn't actually started to play with it in the shop when you have already realized that the turnbuckle doesn't hold station. I should have learned last time I tried a proportional dividing adjuster. If I use 2 turnbuckles, then it would work - but that's to much work. I prefer the lock screw idea better:) See what happens when I have to much free time while the kids are napping - I get drafting happy.

Have a good weekend.

Sean

gmessler
Sun 21 October 2007, 19:18
Interesting concept Sean.
The first thing that comes to mind is KISS. :) You're going to use this thing for 40' of rail (gross) and then it will sit in the corner. :eek: Also I'd have to agree with Dave regarding the distance between those rollers as well. While making mine I tried to keep the rollers as close as possible (10"). The more distance between these the more scrap material you end up with.
As for adjusting the bottom eccentrics, on mine you can see the slots in the eccentrics for holding them in place until you tighten the bolt. On the verticals ones the levers work great.

smreish
Sun 21 October 2007, 19:31
Greg,
I agree with KISS. I was trying to make it a little more friendly since I am making 2 machines to start with, possibly a third by the end of the year. SO, a production model was in my head for future use. You have sold me on the eccentric with the handle for vertical adjustment. I was just concerned with it vibrating to much and changing the grinding depth.

The next challenge is I don't have a mini-lathe in the shop. Yet! Off to buy another tool tomorrow so I can turn those bearing centers. It's a shame I sold my entire machine shop a couple of years ago before I relocated to florida. That Mitsutoyo 3 axis tree mill would come in handy about right now.

Thanks for all your input and wisdom. You keep up this good work I might have to hire one of you guys!

Sean

gmessler
Sun 21 October 2007, 19:51
Sean
I can't tell you how many times I kept looking at the lathe on the Harborfreight website. Even after getting the coupon for 20% off from Gene (THANKS!!!) :) I didn't want to spend that kind of money. J.R. made his look so good with all the fancy turning. I thought about using 3/4" bolts and trying to knurl the pressed on portion but it sounded like a a real PITA. As it turned out the local Lowes hardware store sold 3/4" steel dowel. It was slightly out of round but 2 minutes with my file and the problem was solved. I took the edge off before I "pressed" them into the bearings. A brass hammer, some WD40 and everything went smooth. They are tight enough that I'm not worried about them coming loose, but not so that I worry about them deforming the bearings.

smreish
Sun 21 October 2007, 20:10
Forum,
Just so I can sleep better, here is the skate that I will send to the shop to build....any questions, comments or (hey Sean - your missing something? Thanks for all your help.
Sean

smreish
Mon 22 October 2007, 15:54
Greg,
I must have missed your post, because I did the same thing! I went to Lowes and found the 3/4" round bar as well. I will be working on this week. Gerald, if your watching, I am going to build a true MM first, with the proper rails. In my heart I don't want to deviate from the design that works so well. I was attempting to save a little labor in the shop, but when I really calculated all the drilling and prep time, grinding the rails is actually a time saver by about 10 man hours. I like this design more each day. Sean

driller
Mon 22 October 2007, 20:38
the skate looks like it will work, but...

if you review this whole thread, there is a drawing of bearings that would allow you to use the entire length of the angle.

also, if you have machine shop experience, you can easily make a jig so that the skate of any style runs the full length of the rail, just by adding an exit runway. Not important for the one off machine, but for production, it would be very handy.

Dave

Gerald D
Tue 23 October 2007, 00:57
I don't like that 8-wheel arrangement that lets you get all the way to the tip of the rail. Get your hand-pressure wrong (ie. apply pressure to the wrong end of the skate) and the rail is destroyed/scrap. All this for trying to save about 300mm [12"] of cheap angle iron? Imagine trying to get all 8 bearings to carry equal load . . . . . .

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.

smreish
Tue 23 October 2007, 04:26
Gerald,
Interesting you brought up just a simple screw for the vertical adjustment - I was toying with that last night instead of using the bearing w/lever due to the "one off" nature of the skate usage. This also allows for a much smaller form factor and less salvage. But what's a couple of bucks for angle iron? I was playing with a UHMW/delrin treaded screw, but I like the idea of brass even more due to the heat exposure. I did find my screw was to small of a diameter if I shifted the eccentrics all the way to one side....the screw falls off centerline. Time to try a 1/2-20 tomorrow or larger to ensure a good contact surface.
Sean

driller
Tue 23 October 2007, 06:22
I don't like that 8-wheel arrangement that lets you get all the way to the tip of the rail. Get your hand-pressure wrong (ie. apply pressure to the wrong end of the skate) and the rail is destroyed/scrap. All this for trying to save about 300mm [12"] of cheap angle iron? .


I agree that as a tool, it is not required one uses all the angle iron, and it is easy enough to buy longer and cut off the ends, but...

there was talk about renting or passing around a skate so anyone could use it, so the investment in time to make a "better?" unit might be worth it.

the second application is a production shop that would be making rails all day long. After a while, the scrap pile will get to be pretty big.

Dave

Gerald D
Tue 23 October 2007, 06:46
In a production shop the concentration lapses after a while and somebody is going to push down on the wrong end of that long skate (or actually is going to support the weight incorrectly as the car runs off the rail) . . . .

If I were to seriously do production, that skate would be motorised and run on its own permanent rails - ala the knife grinders.

Hugo Carradini
Tue 23 October 2007, 09:37
Guys just keep that brain storm process. It is a pleasure to see how a project grows and develop with good and smart craftsman.
I am just waiting to make my first order.:)