Jointing thick boards

[joe1086]

An alternative would be to find a nearby shop that could do it for a reasonable fee...

[Danxaz]

"Not sure exactly what the issue is, but what works for me is to arrange the boards in the way you want them to sit when glued up, then put a traingle mark on the assembly, then place 2 the boards face to face ( or back to back ) and clamp them so the tops are even, then plane both at the same time. When you use your jack plane, if your blade or the plane is tilted to one side of the other, they will still mate perfectly. That is , if for some reason, the plane cuts at 88 degrees not 90, once you put them back in the orientation of the glue up, the mating board is at 92, so when put together, they will equal 180 degrees. I just have to keep track of which board is adjacent to which board, and make sure that they are clamped face to face or back to back.

As to a little gap on the ends, we generally want a little gap in the middle, and that is the opposite of what the jack plane wants to do. So either take your last full length cut from one end to the other, then follow by taking a shorter plane , set for a very tiny cut, and plane a small section in the middle, or use a cabinet scraper in the same area. The flip the boards into the correct orientation, and see if there is a gap at the ends, if so, extend the area that you scraped in the middle and recheck."



I dismissed this originally because of how thick the boards are. This is what I would normally do with thinner stock such as 3/4". I figured since the two boards clamped together would leave a 7" surface to joint, it wouldn't work because my jointer plane iron is only 2 1/4" wide. I decided to give it a shot though.

I clamped the two boards together with the long edges facing up. I then treated it like a face and used my jack plane across the grain to flatten the whole surface using my plane as a straightedge to judge for flatness (just like when I flatten the face of a board). Once the surface was flat across the grain I then made sure there was no twist using winding sticks, still using my jack plane. Once the surface was flat and straight, I switched to my jointer plane, taking passes with the grain and being careful to go slow until I was taking continuous shaving the whole length. In theory, this should not ensure a straight edge because my plane is 22" long and my boards are 6' long. It's still possible to create a cupped or bowed surface. In the end, it worked pretty well, I just had to be extra careful to plane the surface evenly with the jointer.

I don't know if the above paragraph makes sense. I couldn't find a source with a video or explanation of this process and if I had the skills, I would film it myself. Basically, the technique I used is, to treat edge jointing thick boards just like you would edge jointing thin boards but since the surface is so large, you can first treat it like you would a board face, then finish it as an edge.

Sorry the quote feature wasn't working for me so I cut and pasted the message above.