#31
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Table almost done
Here is a couple of pics to show what I have been up to for the past 24 hours.
Sean table_weld.jpg bevel_bolt.JPG |
#32
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I added a small detail for future use. If you notice, I drilled the 6mm pilot hole thru both legs. This will allow me to 1) pilot hole from underneath the table to the MDF spoilboard in place - while I have the rest of table clamped square. 2) I am going to TAP these lower leg holes 5/16 so I can attached the vacuum plenum underneath the spoil board. Just thought I would share my thinking.
Gerald, For what it's worth - yes the drill bit did skid while drilling into the beveled edge, but it was very consistent. I only had to deal with about 1/16" of deflection in centerline from the top ledge hole. Seanpurlin_holes.jpg |
#33
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Sean,
Did you drill both at the same time so that you only had one setup? Can you elaborate on your vacuum design / thoughts? I use vacuum clamping and gluing a lot and I am very impressed with how well it works. (Maybe I'm easily impressed). I would love to hear your concept. Thanks. |
#34
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Marc,
I did drill them at the same time. Actually, I drilled all the holes at the same time with a small 1/4" bit and then step drilled 1/4, 3/8 then 9/16" ends. To maintain the tight tolerance on the beam geometry, I drilled the main X beams with a 1/2" dia and the cross members with a 9/16" I was able to maintain a perfect parallel alignment on bolt up! The key to drilling was a really good layout - THE TAPE METHOD WORKS VERY WELL - and a very sharp center point punch to mark with. I know Gerald mentions this on the drawings, but to achieve a consistent layout on structural steel one must work from Centerline dimension and not from the end of a piece steel. Those 1/32" of an inch in cut variation can add up in a hurry! I had to have a quick class on layout dimensioning with my employee's to remind them of that! I hope to have the table completely welded my Monday morning. Then I have to flip it! Anyone up for helping? I'll bring the coffee & donuts. Sean |
#35
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Vacuum Table plenum box detail
Attached is a little detail of the vacuum table plenum I plan on using for the MechMate. This is best built with the MechMate for you to practice on your part making/cutting ability!
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#36
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We have a crude holddown system that is mainly used for flattening wavy boards. 40mm [1.5"] pvc piping that penetrates the table at 8 points. No valves - all 8 points tee'd to one vacuum motor (ala Fein/Shopvac). A bit of a bowl is routed out around the mouth of each table penetration.
The valving, or turning on/off of each point is extremely high-tech. The secret is revealed here. Ssssh, please don't tell anyone else. |
#37
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Sean,
Are you planning to make it out of melamine for the sake of airtightness or MDF and simply paint it. Also, if you are going to silicone it to the spoil board, I assume that you are never going to fully replace the spoil board. Just surface it down to a specified thickness and glue another layer of MDF to it (using the vacuum). Also, is your manifold going to be on the end or the side? What are you going to power the whole thing with? Gerald, how well does the Fein do? I am personnally only familiar with the little vacuum pumps used for vacuum bagging and gluing. I have some pucks that I also use for clamping. I don't have any experience with large area clamping. The first time that I attached a puck to MDF and could pull a vacuum through to hold another piece of MDF, I couldn't believe it. |
#38
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This is another whole can of worms . . . . . how long is a piece of string?
We don't have a Fein "Shopvac" - we do have some other Fein tools and they are top quality. There is one particular model of Fein "ShopVac" that the SB'ers rave about, think it is the Turbo III, but Fein also has some models which nobody raves about. So, let's not help the myth that all Feins are fine. The Fein that is so popular has a reasonably good performance on paper, in terms of suction pressure vs volume, but the major outstanding feature is the sound deadening. It is a very quiet "ShopVac". So, if noise is a major feature in your specs, get the Fein. Otherwise, you could get a naked vacuum motor and have the same performance. Our system is based on a generic vacuum motor. |
#39
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Marc,
A couple of notes: - most likely 3/4" 7/9 core ply - because I have units of it and use it on almost everything I build. - silicon is easy to reseal if you have to reseal the boxes to the Spoil board. Of course, A really good silicon based weatherstrip would probably work as well too. - remember, I am attaching the vacuum plenum's to the steel. Once they are placed, removing them is easy. So, replacing the spoil board from top side is fairly simple. I am going to use capture nuts on the steel (or tap) so the spoil board can be replaced from Topside. - Shop vac's work well, but I will most likely buy a surplus vacuum pump motor to get the adequate suction (about 12-14mm HG) a normal shop vac creates about 5-6 on a good day. Shop vacs work, but they are loud. - additionally, a vacuum pump in line with manual gate valves, is easy control. The motor is small enough that you can put it in a "blimp" box..which is a fun name for an insulated enclosure to reduce db. - I am only vacuum boxing the 5' x 8' are of the table. The last 2 ft is for indexer and "fun stuff to try with a router table" My experience tells me that the surface area of 40' is plenty to hold down the last 2' unheld by vacuum. Plus, the rare times I am actually cutting material that large, a big G clamp is sufficient. - note: if you glue down an additional layer of MDF to the spoil board, you risk sealing it's porous properties...then you will have no vacuum hold down at all. I have made that mistake before and couldn't for the life of me figure out why the board wouldn't stay on the table. :-/ Hope this helps...Gerald, if the forum wants to continue this, can we move the vacuum stuff to the other part of the forum for ease of the rest of the members to find it? Just my 2 cents. Last edited by smreish; Sat 03 November 2007 at 10:37.. Reason: forgot to add a note. |
#40
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Sean I have the same questions as above to with maybe some advice. From you photo's it kinda looks like you making boxes inbetween each C channel that goes the length of the of the y. I only suggest that you install some bracing going the lenght of the x across the y axis. I would do full pieces with lighting holes glue and screw them in. The braces do not need to be air tight but I would bring them up to the underside of you spoil board.
I mention this because if you are able to pull 2.3hg over a 12"x48" area you will be pulling 1psi, so in reallity you would be placing 2,880 pounds or a car within that area. 2.3hg is not hard at all to achieve seeing that over on joewoodworker.com and the zone people are able to get 17hg to 21hg. Some good links about vacuum http://www.engineeringtoolbox.com/va...ter-d_460.html http://www.woodweb.com/knowledge_bas...tml#woodworker http://www.joewoodworker.com/veneering/welcome.htm The build is looking great. |
#41
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Russell,
You caught my other thinking. Yep, I did that quick 3d this morning for Marc's benefit. I didn't show all the internal bracing-nor plumbing. Yes, you could suck the walls in pretty quickly if built "as-shown". NOTE: drawings are for reference only- refer to disclaimer on main page of MechMate.com Last edited by smreish; Sat 03 November 2007 at 11:38.. |
#42
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You might have noticed that I hack a lot of these off-topic discussions out into their own threads when the traffic dies down. I can't move them if someone is busy replying, otherwise his reply is left stranded.
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#43
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Gerald,
I ran across your vacuum hold down on the shopbot forum last night....sexy! Simple and easy to use! Keeping it simple.... If the notation was correct, it was 2001 when you installed that plumbing. 6 years is a good testament. |
#44
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Smreish.
It seems that you bolted cross bars with taper washer. For dismentling and easy transfers ? Then why legs of table welded ? Should not be the cross bars welded or table legs bolted ? Actually I was thinking of bolting all these together for ease of transfers. |
#45
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PK,
The MM table I am fabricating disassembles in 12 parts. 2 sides, 2 ends and 8 cross members. This was specifically done as a "proof of concept" due to shipping requirements here in the US. For a reasonable shipping price, I can send a complete table on a single standard 48" wide x 12' long (super pallet) standard freight. I want to make sure that what I build can be easily shipped. The legs are welded to the main members for 2 reasons. 1. So I can use the cross members to "adjust parallel" on the table before the spoil board is attached. 2. The leg and stretcher assembly is a very STIFF section once complete. This will ensure that the 8" channel and subsequent rail attached to it remain straight and true. I would hate to have a shipper bend my main beams because someone can't drive a forklift properly! I know your new to the MM club, after further study of the drawings you will begin to understand the true gestalt of this great design. Sean Last edited by smreish; Mon 05 November 2007 at 04:40.. |
#46
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Quote:
Isn't it possible to build a frame (yellow lined) and bolt (red) them with legs. This box arrangement is very rigid. For ease of dismentling (though we do not do it often). The door of my converted garage is only 3' wide The spoil board can also be bolted with cross bars and can be lifted as one ? Your decision of welding main members is correct. With bolted sections don't we need very even floor ? You are right I have to read/study/understand a lot, which I am doing right now before start. Last edited by pksharma; Mon 05 November 2007 at 07:26.. |
#47
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PK,
This dwg should clear it up. If you look closely at the picture, I added a 50mmx50mm angle iron section to the bottom of the cross members for bolt attachment. The end frames are smaller and lighter. Keeping it simple, lighter and less steel. Which means less $$$$. Sean Last edited by smreish; Mon 05 November 2007 at 08:17.. |
#48
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Sean,
Oh yes, I magnified the image and doubt cleared, of course this is not welded as I prefer and rigid like box type and <$$$$$. Thanks. |
#49
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fun time skating!
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. |
#50
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Picture no.3 . . . . . never in my life have I seen such a collection of screws, nuts and washers!
(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 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 |
#51
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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 |
#52
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Took me a while to figure out the reference to "trash can" . . . . . . . aaha! the background of these pics!
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). Further discussion on the grinder moved to: http://www.mechmate.com/forums/showthread.php?t=479 |
#53
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Hey Sean, just checking to see how the progress is going. You only have 2 weeks until your deadline. Hope its all going good for you. Josh
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#54
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The day job has slowed progress a little this week. I still think I can make Dec 1st. The base of table is fully welded. Rails are almost ready to be ground now that I have dialed the grinding skate in. I have to admit, setting the grind angle and depth with Gerald's skate is a piece of cake. It only took me about 15-20 minutes to fully adjust and check the runout with a dial gauge. That's better than most manual machine shop mills!
I most likely will need that long holiday weekend to work all the bugs and details out without any interruption from the rest of my shop crew. So, keep your fingers crossed. |
#55
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I can relate to your day job issue. Between the day job and the wife having me build a new vanity for the bath I think I've got the DTs/shakes from not being able to work on my machine.
Good luck making your deadline. What were your plans for the placement of your control box? |
#56
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Stick it on the wall next to the machine like Gerald's. It's a perfect place and keeps it fairly away from the dust fall-off. Interestingly enough I visited my old Multicam4896 yesterday. It's cabinet is on the end, under the machine. The dust has begun (again) to destroy the stepper cards. That location is good for about 1 card replacement every year! I guess good for the Multicam service rep...bad for the owner. Thus, I like up and out of the way. I don't feel like buying new gecko's every year.
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#57
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Point taken. On the wall it goes.
Thanks Sean |
#58
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MultiCam's position is good for shipping a pre-assembled and tested machine from the factory, and also for guys who have 5 MultiCams in a shed with no walls nearby. I think us DIY'ers have a slightly different perspective.
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#59
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I've been careful to incorporate everything Gerald and Mike Richards have told me because I want a machine that is as bulletproof as possible. That's also why I love this design. It's industrial quality. All my visitors have asked how heavy it is so I just tell them to try to pick it up. No one but my son has been able to get one of the legs off the ground. He'll be handy to have around when I get ready to move it out of the garage.
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#60
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Got Blue?
The shop degreased and painted the Mamba today. They even bondo'd up the ends for me so they are nice and smooth.....I'll thank them later after I crash into the end chasing a broken bit!
It's nice to see some parts of the process happen without me actually doing it! |
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