Problem with a fretsaw

[mbrown]

I recently borrowed a portable fretsaw from a friend, in order to make a wooden puzzle. After completing one puzzle with no problems, I began a second, but half way through a longish cut, it stopped working - every time the wood was pushed against the blade, it caught and stopped moving up and down. I guessed that the blade was blunt and changed it, but this made no difference. I then took the saw to pieces, thinking perhaps a stray bit of wood was stopping it from moving, but there's nothing obvious. Does anyone have any ideas? The saw is a Shapercraft Model No 1000, and I believe it's around 20 years old, or possibly older. It's made by Spiralux Handtools Ltd, Gillingham, Kent. The design is an electromagnet which is turned rapidly on and off, pulling a metal plate up and down, to which the blade is attached. The top of the blade is attached to a sprung arm.

Thanks.

 

[Gill]

How thick was the wood you were cutting and what sort was it? I've used a Spiralux before and found it struggled with plywood greater than 4mm thick.

Another thought is that electromagnetic saws stop when they come into contact with something soft, like flesh. That's why fire rescue services use them for cutting people out of wrecked cars. Could it be that the wood you're trying to cut has loose fibres against the blade which are simulating this effect?

Gill

 

[mbrown]

Thanks for your help.

I don't think it was the thickness or texture of the wood, because it worked to start with on other pieces the same, and it failed to cut other offcuts of the same ply that I had.

With a bit of fiddling around, we discovered that it still cuts fine if the top cover is removed, but doesn't when it's in place - so presumably it's something on the cover dampening the vibrations of the plate to which the blade is attached.

Anyway, I finished making what I was making, and the owner of the saw says it's not been used for a good few years, so I won't waste too much time trying to diagnose the problem!