Hold-down Cam System

[patricktoomey]

Following Robert's lead (http://www.talkshopbot.com/forum/messages/29/17404.html?1168354721#POST44861)
I made a peg board with 1/2" holes laid out on a 2" grid. I then made cams with 1/2" holes 1/8" off center. Finally I came up with some bench dogs with the dowel set so that you can turn it to get different offsets to minimize the amount of shimming needed to work with the cams. Turning it to a given side gives me 1/4", 1/2", 3/4" or 1" spacing. The system works incredibly well and it is going to save me enormous amounts of time by eliminating clamping and screwing of small or odd shaped pieces. Here are some pics showing how well it holds non-square parts. I can also clamp long boards with this system and pull some warping out by jamming it into the bench dogs with the cams.


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Thanks to Robert for making his original post. It works so well that I wanted other people to see it again and hopefully try it out.

[paco]

Nice!

Thanks for sharing!

I may very well try it out on a spare time session.

PS: FireFox user; check out ScrapBook Add-on (http://amb.vis.ne.jp/mozilla/scrapbook/). It save me huge amount of time... and infos!

[Brady Watson]

Patrick,
In the past when I have used side-clamping setups, I have found that the part can lift when clamped...throwing off the Z. Have you found this to be the case with your setup?

Looks good by the way! Thanks for posting.

-B

[myxpykalix]

patrick,
Let me ask what might be obvious to others but not to me. Did you drill this series of holes in your spoilboard, or is that a seperate sheet of mdf? If in your spoilboard do you have a vacumn table? if you do does that cut down on your vacumn?

[patricktoomey]

Brady, the only trouble I've had with lifting so far is with up spirals which I rarely use. I normally use compression spirals, straight cutters and ball end mills. None of those have given me any problems yet. I am mostly using this system to hold down parts to relief carve so I'm generally taking light passes with low stepovers and not putting much force on them. If I was going to do something with significant cutter forces I would probably hold it a different way or use hot glue or double stick tape as a backup under the piece.

Jack, this is a separate board just for this purpose. I lay it on top of my spoilboard. I do have a vac hold-down system which I will sometimes run with the peg board in place to make sure it's flat. But generally I just clamp the peg board in place to be sure it doesn't walk around due to cutting vibration.