Inexpensive quasi-bar clamp
Inspired by reading this blog post: a re-application of using wedges against dogholes on woodworking workbench top to hold work.The idea is to enable the user to glue up several boards into a large, wide panel (e.g. a workbench top), without having to run out and buy a zillion long clamps.
I'm envisioning lengths of 1" x 4" or 2" x 4", with the end pieces being essentially the same thickness as the panel being glued up. Pound the wedges in to exert clamping force; if the end pieces are as wide as the panel being glued, then the long pieces keep the component aligned. (But you'd want to varnish and/or wax the inside surfaces, to keep 'em from being glued to your workpiece; or, wrap 'em in wax paper, I suppose.
The T-shaped piece is made out of thin plywood, and is inserted between the wedge and the edge of the workpiece, with the smoothest side against the wedge. Its purpose is to minimize the sideways sliding force caused by the wedge sliding sideways against the edge of the workpiece.
This is totally theoretical; never tried it. But, reasonably quick, and (presumably!) inexpensive and effective.
--GG
posted by Gye Greene @ 10:11 PM
2 Comments:
I saw some guy use wedges for clamping in some other post somewhere, so thanks for the reminder about it! A couple questions:
1. How does the frame join together? Dovetailed? Or just use a bazillion nails? I'm just wondering how good the joinery has to be to hold up to good clamping.
2. Is the left diagram a different view of that on the right? So are the end pieces angled at all?
3. I'm not quite sure I'm tracking on the T. Maybe I should just try banging one of these together and figure it out as I go. Cuz I like the concept.
I do have four 48" f-clamps, so maybe with those I could get by with just two of these frame clamps. Or maybe I'll just see how it goes with the first lamination - who knows, maybe if I take it one board at a time, my f-clamps will be sufficient!
>
> 1. How does the frame join together? Dovetailed? Or just use a bazillion
> nails? I'm just wondering how good the joinery has to be to hold up to good
> clamping.
Oh, definitely **not** dovetailing!!! 'T'would somewhat defeat the purpose.
I'd reckon 4-5 nails -- set in sufficiently from the end of the board -- would be sufficient. We're dealing with shear-forces, not pulling the nails out.
> 2. Is the left diagram a different view of that on the right? So are the end
> pieces angled at all?
Sorry -- should've labeled the different views. Not sure I understand the Q. I'd probably cut the wedge and the end piece from the same piece of wood -- which would ensure the angles match.
> 3. I'm not quite sure I'm tracking on the T.
It's drawn from the wrong perspective, relative to the other two drawings. Goes between the wedge that you whack with a mallet, and the workpiece. Without the T, the wedge might move the workpiece laterally (or mar the surface); **with** the T, the "legs" of the T grab on to the long boards of the quasi-clamp, which mean that the wedge shouldn't make the workpiece move (although the clamp itself may be displaced...).
> Maybe I should just try banging
> one of these together and figure it out as I go. Cuz I like the concept.
>
Thanks! :)
--GG
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