Top thicknesing, jointing, and joining

Had some troubles with the top, learned a few lessons. The first thing I did was sand each bookmatched piece individually using a drum sander machine. I did this until I could see the grain pretty good on both sides of both pieces. Now that I could see the grain, I chose which sides should be joined (tighter grains for the joint).

I then ran the joint edge through a machine jointer to rough out the joint.


Next I made a shooting board jig, very simple version, using a couple of clamps, and a couple of spare boards of mdf laying around the shop. I tried using a cheap jack plane that I borrowed and it did not work well. I sure a lot of it was my skill too, as this is a very difficult process, but I just couldn't get the joint to have absolutely zero gaps when candeling. I then tried to put sandpaper on a block and sand the joint while still in the shooting board. I got close, but never could get an absolute perfect joint. ( I actually never tried to put sand paper on the plane while doing the shooting board, may try that next time).

This was as good as I could get it, but there were slight gaps still when candeling. I glued the joint together using LMI white glue and the baton and nail method. Next clamped a piece of wood on top of the joint (with wax paper as well) and let sit over night.

The joint must not have been good enough, or the glue was a bad batch, because the joint failed while I was thicknessing the top using a drum sander planer. While I was very frustrated, I was actually glad the joint failed then and not after the instrument was finished.

I built a new jig (got the idea from the sand paper joint jig method from luthier suppliers) using 1/4" plate glass, mdf, and sandpaper. It didn't work at first because I was trying to glue the sandpaper to the glass, the glue made the surface uneven. So I tried it without any glue and just used the fence as a clamp. This worked perfectly and I then had a perfect joint with no light when candeling.

This time I glued the joing once again using the baton and nail vise, but this time used titebond original, clamped, and let sit for 24 hours.

The joint was now perfect, and was undectible to the eye, and the joint felt much more stable. We then thicknessed the top using the drum sander planer until the top was approx. 1/8". I then sanded with a block and sandpaper until the board was flimsy enough that it made a sheet metal sound with shaking it. Final thickness is 1/8" in the middle, and slightly less than that on the sides.