I recently made several puzzles from 3/4" thick pine for my grandkids. I got frustrated because I had to do a lot of sanding and fitting, so the pieces were easy to remove and put back in. I even trying adjusting the scroll saw table angle to the blade, and that did not help. The biggest pinless blades I had in stock were No. 5's.
I did the standard alignment test where you start to saw a piece of 2x4 [1.5 inches tall], then rotate the piece 180 degrees and see if the back of the blade fits in the saw mark. It fit fine, and there was no difference if I put in 3 cardboard shims under the table also.
I ordered some No. 7's and some No. 9's, which I just received.
I decided to do a study and see if I can figure out the right combo for making future puzzles.
I took a segment from one of my puzzles, and that became my test fit piece for the study. The study variables were:
-Blade No. (7 or 9)
-any shims under that scroll saw table, which changes the angle to the blade.
-direction of scroll sawing (either clockwise or counter-clockwise)
The output was if the piece was free and would easily fit in and can be removed easily.
Even with shimming the table to change the angle, using a No. 5 blade does not give enough clearance between the pieces to paint the sides. On future puzzles, I should just use a No. 9 Blade and I should have no more issues.