Useful diy clamps

Hand tools required and/or preferred to achieve a high level of Craftsmanship
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Dave Bagwill
Posts: 5951
Joined: Tue Dec 13, 2011 7:44 pm

Useful diy clamps

Post by Dave Bagwill » Sat Jul 07, 2012 7:50 pm

Interesting - useful for a number of planing and scraping tasks.
Would any eccentric shape with offset holes work as well?

http://www.garagewoodworks.com/video.php?video=v39
-Under permanent construction

Robert Hosmer
Posts: 167
Joined: Tue May 08, 2012 7:30 pm
Location: Southern IN

Re: Useful diy clamps

Post by Robert Hosmer » Sun Jul 08, 2012 9:07 pm

deadedith wrote:Interesting - useful for a number of planing and scraping tasks.
Would any eccentric shape with offset holes work as well?

http://www.garagewoodworks.com/video.php?video=v39
Appears to apply pressure in the same manner as the cam clamp, with which we are all too familiar!

Bought a bench many years ago at a garage sale that had a couple sets of these in various sizes.
They were made out of plywood. One set was small and 1/4" thick; other set was larger and 3/4" thick.

Easy enough to make yourself; if you don't have a template as shown in the video, use a French curve and do some experimental drawing.

They work well, but (in my experience anyways) there are two caveats:
1. While they are "adjustable" within a narrow range, working with widely varying widths of stock means multiple dogholes in the bench.
May or may not be a concern for you.
2. These grip fairly well, but keep in mind all the pressure is applied at a single point along the curve, which may lead to denting at the clamping location of the workpiece.
Really depends on the nature of your work. If you're working initial stages of a piece and have yet to work the edges, no big deal.
But if you've already jointed the edges, or you are working a piece that does not have enough "cleanup room", it may be better to use a stop block or a clamp with a wider clamping surface.
I have tried inserting cauls between the clamps and workpiece. Worked OK for light-duty operations like final scraping, but not so well for planing.
Planing, or even heavy scraping (such as that encountered when using a scraping plane), caused the workpiece to slip in the cauls. The caul is used to prevent marring/denting, but it also spreads the clamping force out enough that there is not enough clamping pressure left to resist the longitudinal pressure you're applying.

Simple in design, fast-acting, and easy to make. Just keep in mind that like any other clamp, it has limitations.


Rob
Always have plenty of sandpaper; it's rough out there!

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