Just finished an interesting read of old threads on spring joint. One of the first threads had my question in the last reply, but no discussion.
My preference is to follow the jointer with a #7 until continuous shaving, then spring the joint with 2-3 passes starting and stopping a couple inches from each end, followed by one full length pass. Very tight joints result, although I usually clamp rather than just rub. But when gluing up a 1/2″ thick panel of ash, I used hot hide glue, rub with no clamps, and the joints were very good.
My question is how spring joints should be applied to a multiple board top, say a table top with six boards. In theory, at most two joints should be sprung and glued at a time, no? Start in middle, after curing spring next joint on each side, then final joint? Not a problem if building entire table and room to set the top aside. In earlier times, was not a problem because craftspeople had much wider boards . . .
Thanks for your thoughts.
Replies
I never have ever worried about springing joints. My 12" jointer has a lever that actually will do it in one pass for me, but I've never used it. I've never ever had a glue up come apart on me. Todays modern adhesives are so good that as long as you take the time to properly prepare the edges of the boards to be joined, then just have at it. They won't come apart.
Just my .02. Other opinions may vary.
Jeff
For what it's worth, I've built table tops just as you describe without any trouble. I don't do it out of any concern for the glue, but mostly to avoid the antithesis -- having the ends of the joint sprung, in which case, you might have them open up at some point. It also reduces the number of clamps you might otherwise use. Theoretically which a sprung joint, you could get away with one clamp in the center. However, I've always worked toward an extremely slight opening at the center of the joint -- just a couple of thousandths is sufficient.
I use a different method that you might consider. Instead of starting and stopping your cut a few inches from the end, try starting with the plane body parallel to the edge and gradually skew the plane as you move toward center, and then back to parallel as you move to the other end. I'm sure that a lot depends on your tools and your touch, but it works for me.
Verne
If a tree falls in the forest, and no one is there to cut it up and make something with it . . . what a waste!
Edited 2/15/2009 9:49 pm by Thorvald
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