Using a planing sled

[skcrab]

Built a sled to use with my dewalt planer similar to the one in the last issue of FWW. Anyway, my question is, what is the best way to use it to eliminate the bow in a rough board? I'm having pretty good success getting out the cupping with the concave side down, but with the bow, I can't seem to reduce it very much. I am rough cutting the boards to size (30-36") and I have tried positioning them with the concave side down and shimming the middle and with the concave side up and shimming the ends? How should I be doing this? Any other advice or tips?

Thanks!

p.s. I hope to buy a jointer soon, but for now this is the best I can do!

[fredfighter]

positioning

It is possible that there are residual stresses so that as you plane it down it keeps bowing more--sort of like what happens sometimes when ripping narrow strips.

Two suggestions:

1) Crosscut it into shorter pieces and use it for shorter pieces.

That was not an option when I was using bowed stock for a cedar chest--unless I wanted to make a jewelry box instead so:

2) Try to use joinery that straightens the boards. For the cedar chest mentioned above I bookmatched and edge glued the panels so that the direction of the bowing alternated. Between that and the dovetail joints on the corners of the chest the sides all look flat. I never put a straight-edge on them to see HOW flat.

Maybe that worked for me because cedar is so soft.

[Duane Bozarth]

Real tough to keep the spring out by shimming. Unless it's really severe you'll probably do as well or better w/ hand jointer plane or belt sander.