cutting puzzles

[woodknotsbyjcr]

I'm fairly new to scrolling about 6 months.I recently started cutting puzzles (solid wood ) a few times I have had a couple pieces that won't slide both ways IE front or back.I've checked that table is sq to blade i have a porter cable scroll saw and im using fd-psr#5 blades.is there something I'm doing wrong.

[Arcy]

Hi, JCR and welcome to the forum!

It sounds like the blade is bowing when you cut: even though it was square at rest, pressure push it out of square while cutting. This can be caused by several things. Make sure your tension is high enough. Feed the wood slowly so that the blade can finish the cut without pushing back (especially while turning), and take care not to push sideways against the blade.

If you look closely where the pieces bind you should be able to see where they aren't vertical.

If you'd like to post some pictures we'd love to see what you've been making!

--Rob

[tgiro]

Proper tension is really important. Make sure the blade responds with a high-C sound when you pluck it, also, it shouldn't bend more than about an 1/8th-inch if you push against the side of it.

It took me a little practice to learn not push the piece to the side when I was cutting corners. I took some 1/2-inch & 3/4-inch scrap and drew some circular patterns on it and practiced quite a bit. But, once you learn it - it will be forever.

Good luck and we really need pictures so see how you are doing.

Tony

[sawdustus]

I agree, side pressure is the culprit. It just takes some practice. I like to use a very tight blade, a sharp new blade, moderate speed, and as little pressure as possible, especially when I make turns. Slow down your feed speed and pressure when you are making tight turns. I tend to find myself putting more side pressure on when I make a clockwise turn than when I make a counterclockwise turn...but that's just me.
I can usually tell when I am putting too much side pressure on it because the sound changes. As the blade dulls, the speed at which it cut also slows way, way down. Don't be too frugal about changing blades.

george

[jigsue]

Hi Rob

The comments above make sense however, because your pieces slide in one way and not the other, the problem appears to me to be that you are cutting at an angle. Before you cut your puzzle, ensure that your blade is at 90 degrees to the table (use a protractor or a set square). Cut a test piece and check that the cut is at 90 degrees. Then with the blade highly tensioned, cut slowly, let the blade do the work and try not to "bow" the cut. If cutting lots of puzzle pieces, repeat the checks from time to time. Eventually, it comes naturally, honestly!

With those you have already cut, it may be possible to sand them to fit - for a long time, I had to do this with most of my thicker puzzles - practice, practice, practice!!!

Good Luck
Sue

[Cutter141]

I use a mach 3 blade for hardwoods. I use a lot of cherry, walnut and even African Mahogany. I have had the same problem you describe. My solution is to plane the wood to a little more than 5/8's thickness so the puzzles still stand. 3'4's thickness makes the blade bend more, and personally I like the thickness to be a little less. Whenever the pattern has a bend (like with every key), I take a little extra in the kerf. I know this is back and forth a lot, but in the end it saves a lot of time in the end. Because I use some very hard woods, I take a little extra in the kerf even when there is a slight bend in the pattern. With practice, you can feel when the blade is straight, especially when you go back just slightly and then forward. As others have suggested, take the curves slower, but also take a little extra in the kerf and that should help.

Mel