Woodworker's Journal 1994-18-5, страница 20

Photo J: A clamp for each rail suffices for most mortise-and-tenon frames. Fur through-mortised or hridle-jointed frames, position the clamp as close to the protruding tenon as possible.

Photo H: A sharp rap with a hammer on a hardwood block will usually force edge-joined faces into alignment.

joint (top and bottom) indicates good coverage. Now. I'm ready to clamp.

Most of the time, I find it prudent to apply a bead of glue along both mating surfaces, spreading it to cover each edge uniformly

before pressing the two together. You don't need any fancy gear to spread glue. A thin strip of w ood, an acid brush (cheap, bristly, disposable brushes sold at most hardware stores), or a small paint roller works fine (Photo G). The object is to spread the glue evenly and quickly.

After placing the boards on the supporting clamps, I tighten the center clamp first and work my way outward. 1 crank each clamp down just enough to engage the edges, then check to see that the faces are aligned before moving to the next clamp. Sometimes I can align the faces with my fingers, but white glue '"grabs" very quickly. I usually persuade the surfaces into alignment with sharp blows from a hammer on a hardwood block (Photo H). At the

Photo I: Check to make sure that the faces of the boards rest on the pipe or bar. This Hill help keep the panel flat.

same time. I check to make sure that the board faces are flush with the clamp bar or pipe (Photo 1). The edges frequently creep up the jaws, so I knock them down onto the bar again with hammer and block. (Don't try to drive the top clamps down onto the boards: loosen the jaws and reposition them. )

As you tighten each clamp, give the previous ones a little turn to keep them engaged. Finally, when all clamps are drawn up and the faces are aligned, tighten all the clamps to a more or less uniform pressure. Remember, it shouldn't require white-knuckle pressure to pull the joints together enough to make a virtually invisible seam. If you have to crank down with excessive force, something is wrong, which you should have discovered and corrected during your dry run. It's probably too late to fix it now.

If you're gluing up a number of panels and have enough

Photos R and L: Two ways to clamp a mitered frame. Use perpendicular pairs of bar clamps to keep (he mitered surfaces aligned (Photo K). A simpler method is to glue angled blocks (the miter offcuts usually work) to the rails and stiles and then draw the joint together with quick-action clamps (Photo L). Because the pressure is applied at right angles to the joint, slippage is minimized.

clamps to do several at a time, you can stand a clamped panel up against a wall to make room for the next one. However, take care when leaning the clamped panel that the clamps stay aligned to prevent any twisting.

4fi September/October 1994

Woodworker's Journal