Thanks: 0
Likes: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 13 of 13
Thread: Clamping advice?
-
22nd January 2012, 06:44 AM #1SENIOR MEMBER
- Join Date
- Sep 2008
- Location
- Maryvale, Queensland
- Posts
- 2,338
Clamping advice?
Hey all,
Something you'd think is relatively easy is causing me problems. How to clamp my workpiece to the spoilboard.
I've tried this method CNC Machine Workpiece Clamping with the shelf support pins and wedges, and it doesn't seem to work very well, but it may be my implementation of the technique.
First, I found out after filling my spoil board with 5mm holes, that 5mm shelf supports are smaller than 5mm!! As a result, they angle out a bit when pushed against.
Secondly, I am using 12mm particle board wedges. Do the wedges have to be the same thickness as the workpiece for this technique to work? When I use it to try and hold a piece of 70x35 pine stud, the stud tends to tip up on the side where the wedge pushes against it. He also says in the instructions that he doesn't find clamping the 4th side to be necessary, but in my case it is relatively easy to end up moving the piece in that direction.
I ended up running a long piece of of ply across each end of the spoilboard with a bolt in to hold in the T-slot of the CNC bed. This I used to clamp the wedges once they were toght enough to hold the workpiece securely. But yesterday, ying that method to hold a waxed piece of HDPE, the stuff seeme djust too slippery for the wedges to hold anything.
Either way, my "simple" wedge clamp is turning into a frankensteins monster of clamping systems.
My goals in a clamping system, since I am doing mainly small workspieces, are
1. Not needing to clamp the top of the workpiece due to my small workpiece sizes
2. Not screwing into the spoilboard every time
3. Not needing To use the T-slot since the spoilboard is covering it
4. Easily adjustable
I found one reference on the forum here to "rods gap clamp technique", but I can't find out what it actually is. I've seen some things similar to the wedge thing, but using cam shaped side pieces, but that would seem to have the same slippage problem as the wedges?
Anyone have any suggestions what I may be doing wrong, or something better I should be doing?, or am I just asking for too much with the above? Most of the stuff 've fouand on Google uses T-slots, but with the spoilboard in place, you can't get to the CNC bed where the T-slots are.
Thanks. Russell.Pen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
-
22nd January 2012 06:44 AM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
22nd January 2012, 10:53 AM #2GOLD MEMBER
- Join Date
- May 2003
- Location
- Perth WA
- Posts
- 3,784
Bypass the wedges - they are OK but apply sideways pressure to hold something down is not ideal. Also it can buckle up your workpiece if your wedge is too firm.
This is what I use for clamping on a T slot table - see photo
It's quick to clamp and clamping forces are where they should be.
Eventually for your small pieces you can use a vacuum table. You can also use double sided tape for those - the thin film type and not the thicker foam type.
There are other solutions but I'll leave that for somebody else to comment about.
.Cheers,
Rod
-
22nd January 2012, 02:55 PM #3SENIOR MEMBER
- Join Date
- Sep 2008
- Location
- Maryvale, Queensland
- Posts
- 2,338
Thanks for the picture Rod. Those bar clamps, in a much more primitive form using wood, were what i was trying to do, but my first attempt was too thin and the wood actually bent and didn't hold properly. Unfortunately at the moment I don't have longer bolts to use for thicker board, and don't have metal bar to use instead.
Russell.Pen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
-
23rd January 2012, 01:54 AM #4GOLD MEMBER
- Join Date
- May 2003
- Location
- Perth WA
- Posts
- 3,784
Yeah I gave up on timber as it requires 19mm thick to have enough force to hold the job. That thick means the collet nut will hit the timber on a deep cut close to the clamp. The steel on mine is 25 by 8 flat bar.
Cheers,
Rod
-
23rd January 2012, 05:37 AM #5Member
- Join Date
- Jul 2009
- Location
- Detroit, Michigan
- Age
- 60
- Posts
- 72
I've been using this method with excellent results.
Vectric Forum • View topic - Keystone for arched casing
-
23rd January 2012, 06:37 AM #6SENIOR MEMBER
- Join Date
- Sep 2008
- Location
- Maryvale, Queensland
- Posts
- 2,338
I've never seen anhing like those threaded inserts available around here. Also, aren't they a problem then the bit hits them if going through a workpiece? He also mentions issues with the workpiece lifting, which is where I started having problems.
Any suggestions on an easy way to find metal bar, for someone living in a supply-challenged area?
Russell.Pen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
-
23rd January 2012, 07:12 AM #7Member
- Join Date
- Jul 2009
- Location
- Detroit, Michigan
- Age
- 60
- Posts
- 72
I just used T nuts in my table, with a bolt through the cam clamp.
Mine creates a tremendous amount of force (enough to push the bolted down fence out of position), and I've never had any lifting. It's also very fast, especially when running multiple parts.
Something you'd think is relatively easy is causing me problems. How to clamp my workpiece to the spoilboard.Gerry
-
23rd January 2012, 12:22 PM #8Senior Member
- Join Date
- May 2009
- Location
- Gosford,NSW
- Posts
- 135
Ger21 is absolutely right.. fixtures and clamping methods are half the battle when making parts.
I dissagree that side clamping is a bad idea... depends on the job and the material. I made myself a bunch of these ecentrics Mitee-Bite Products Co. for the metal jobs I've been doing and they work very well. Pins as stops are also great but need to be vertical and solid... personally wouldn't trust holes in MDF.. too soft.
I'd suggest yopu make a peg board plate out of either alloy or steel with threaded holes every couple of inches and then clamp that down to your spoil board.
I use the T slots that are machined into the bed blow the spoil board (which is sloted) to hold various sheet work of clamping fixtures down.
double sided tap is also very good but won't hold to HDPE... stuffs sliperier than snot! If the part has hols in it then cut those first thru bolt to table/fixture then cut profile...
No one technique is going to be perfect for every job and sometime it will take several techniques to get a satifactory setup.
Cheers
Mark
-
23rd January 2012, 12:55 PM #9SENIOR MEMBER
- Join Date
- Sep 2008
- Location
- Maryvale, Queensland
- Posts
- 2,338
Yeah I guess I'm being hopeful for a One-size-fits-all solution.
I've found some meter long lengths of aluminum at Bunning this morning. The plain flat stuff is too flexible, but the have various folded shapes. So I got a piece of 3 sides 'U' shaped stuff that I'm going to try putting together like Rod's suggestion.
I also saw some silicon edged, bent teardrop shaped doorstops in BigW that I thought might act better as sideways cams. I figured my last solution failed as it was only wedged on one side, as the wedge didn't have enough grip. If I had two of these, one for each side, they may provide the grip and balance to side wedge better. But at $7 each, I'll try other things first.
PerhaPs I also need to make multi-sized spoil boards as well, and then use the T-slot base to clamp both the work and spoilboard at the same time.
You guys have given me some new ideas at least Thanks for the suggestions.
RussellPen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
-
23rd January 2012, 01:06 PM #10SENIOR MEMBER
- Join Date
- Feb 2008
- Location
- Australia
- Posts
- 988
How about gluing strips of spoil board down and using the existing T-slots?
I used a gel based contact adhesive on my machine with MDF, and it holds very strong. I have yet to find out how fun it is to remove but I don't plan to do that any time soon, when it gets too thin you just glue a new piece on top of the old.
-
23rd January 2012, 01:30 PM #11
For wedges you may like to try either the large spacers that are used for tiling, or the even better ones used for sheet flooring. The latter have steps and can lock together.
Bob Willson
The term 'grammar nazi' was invented to make people, who don't know their grammar, feel OK about being uneducated.
-
23rd January 2012, 02:45 PM #12SENIOR MEMBER
- Join Date
- Sep 2008
- Location
- Maryvale, Queensland
- Posts
- 2,338
Yes I had that thought, and for the exact ungluing reason you mention, decided against it. I had a subsequent thought out routing the tracks but not all the way through, leaving the last inch or so solid, but I didn't know whether that would provide enough support to the rest of the structure. You could leave both ends solid, but that's more of a bather if you need to move the bolts outside for anything.
Russell.Pen Affair Craft Supplies - Cheapest Pearl Ex & Pemo Polymer Clay in Australia
http://craftsupplies.penaffair.com
-
28th January 2012, 09:30 PM #13Intermediate Member
- Join Date
- May 2011
- Location
- Perth
- Posts
- 27
Similar Threads
-
Clamping Jigger
By rhossack in forum WOODTURNING - PEN TURNINGReplies: 5Last Post: 9th June 2011, 06:48 AM -
In need of a clamping solution
By mrstevo in forum WOODWORK - GENERALReplies: 12Last Post: 15th March 2007, 09:05 PM -
clamping ?
By Tonyz in forum WOODCARVING AND SCULPTUREReplies: 5Last Post: 7th November 2005, 07:40 AM -
Happy clamping
By Soren in forum WOODWORK - GENERALReplies: 17Last Post: 30th May 2005, 08:52 PM -
clamping
By Shaty40 in forum WOODWORK - GENERALReplies: 9Last Post: 26th December 2004, 02:52 AM