Fellow woodworkers:
I am edge joining 8/4 stock at 22.5 degree angle for parts of a trestle base on a dining room table. As this is a major structural part of the table, I need the joint to be clean and strong. Any advice on best ways to align the joint (spline, biscuits, etc.) and a solid clamping procedure during the glue-up? I have considered using angled scrap blocks clamped to the work, then using them a camping purchase; as well as using strong tape perpendicular to the joint. I’m not convinced that either of these methods will work on 8/4 stock. This site has been very helpful to me in the past and I look forward to your comments!
Replies
Dominos or splines for alignment is perfect. How many parts are there and how many joints? I had some coopered work recently where I needed a bit over a 90° turn. I just milled extra parts and used tape to roll up a cylinder with the joints having glue and the rest just acting as cauls. once they were taped into a ring I used bicycle inner tubes to clamp them tight. Worked like a charm.
I've done the same thing with hose clamps, but they do some damage to the peaks.. so only go that way if you plan on rounding off the outside of the coopering.
I've used ratcheting straps, like those used to tie down a load in a truck, to clamp heavy pieces for bending. You can get a lot tighter clamping than with tape.
I had to glue 2 pieces of oak at a small angle for a cabinet I made a few years ago. I'll attach a picture of how I did it. I made two clamping pieces, and used regular bar clamps. This is what I advise if you are just gluing up 2 pieces. If you want it accurate, make a platform (I used the cabinet itself) with 2 or more rails that have the 22.5º angle to loosely clamp the pieces to. Make two clamping "cauls". The principles are:
The surfaces the clamps push against are at a 22.5º angle, so that they are parallel to the joint surfaces.
The centers of the surfaces that the clamps press against line up with the center of the joint surface (n other words, the clamps are pressing straight toward the center of the joint, rather than above or below it.)
The "cauls" have hook pieces that contact the opposite edges of the boards and prevent the cauls from sliding toward the joint from the clamp pressure.
I use a similar technique for gluing up miters. The second picture is of a glue up recently. Here I just clamp the cauls to the frame pieces with a couple clamps, as I can't use a hook.