Thread: Need help finding why blades keep breaking.

Originally Posted by Babylon5

Hi, I've got a Carbatec 16" variable speed scroll saw that is only a couple of weeks old. Everything seemed to be fine at the beginning but ever since I've started cutting out jigsaw puzzles I've had issues with blades breaking.

Blades are Olson 5" Pin end 18.5 TPI thin kerf. I've checked that the machine is cutting straight/aligned. Not sure on tension, I've tried to run it both with less tension and higher tension. Attempting at lower tension just makes the blade too prone to sidewards movement. Marine plywood 16mm thick is what I'm attempting to cut through.

The majority of blades it seems are snapping at their thinest part of the blade. Would I be right to presume that doing the tight curves is putting too much stress on the blade?



I'm a beginner scroll sawer and the only way I can cut the tight curves is to take it nice and slow and rotate the wood without trying to put sideways pressure on the blade.

Should I be taking the curves at a much faster rate? I've tried with a thicker blade but just ended up breaking them also.

From reading other threads, it seems that multiple reasons can cause blades to break but this is not only expensive but also frustrating when I'm breaking 3 blades and I've not even finished cutting out half of the jigsaw pattern.

What speed are you operating at. rule of thumd go at a fast speed and feed the timber slowley. What blades are you using, are they a skip toot blade. I use pinnless blades usually no 2 & 3 and cut upto 35mm and do not break that many blades. When cutting ply the problem can occur while cutting the glue that binds the ply together has a tendcy to gum up the blade. If you are usind a large tooth blade it will make it harder to turn it. The blades I use last at least an hour or more of cutting depending on th timber.

I hope this is a help

Phill

Originally Posted by Gunado

What speed are you operating at. rule of thumd go at a fast speed and feed the timber slowley. What blades are you using, are they a skip toot blade. I use pinnless blades usually no 2 & 3 and cut upto 35mm and do not break that many blades. When cutting ply the problem can occur while cutting the glue that binds the ply together has a tendcy to gum up the blade. If you are usind a large tooth blade it will make it harder to turn it. The blades I use last at least an hour or more of cutting depending on th timber.

I hope this is a help

Phill

Thanks, I'll give it another go using it on pine or other soft timber instead of plywood. I don't believe the blades are skip tooth (I'll presume that skip tooth blades look like they are missing teeth).

I am running it nearly at full variable speed, I adjust the speed back a little bit from top speed as it reduces the vibrations.

Shane.

When I first started scrollsawing, I found I had a tendency to push to the side when cutting curves, causing lots of breaks. I really have to concentrate not to do this.

So glad someone else has this problem with breaking blades, I too break them on puzzles made from pine, When cutting on the curve
It seems its just practice practice practice,, so im told, BUT so frustrating & dis hearting !
cheers horse

Originally Posted by horse123

So glad someone else has this problem with breaking blades, I too break them on puzzles made from pine, When cutting on the curve
It seems its just practice practice practice,, so im told, BUT so frustrating & dis hearting !
cheers horse

I think I may have found some of the problem why my blades were breaking. I decided to no longer use the foot hold down clampy thingymajig (sorry no idea what is the correct name). But I think that was down too tight and when I was turning the pieces instead of the wood recentering, the foot was causing it to hold the work to the side, thus causing blades to break.

I also readjusted the plastic clearance insert to make sure it was level and flush with the metal table.

When I attempted to finished the jigsaw that had already broken three blades, I was able to complete the other half without loss of blade.

It was getting expensive as I had bought the blades from Carbatec @ $12 a pack

Shane.

You can also buy spiral blades that cut in all directions, they dont break as much as the straight blades. well thats what I have found.

Shane
I have been using canfor and silky oak to do the puzzels in 20-25mm. had no problems with either of these timbers. I have been using a no 3 blades and they come out realy great. There are a number of places you can get your blades cheaper. I get them from the US, cost arround $4.50 per12. Pimmed blades a slightly more expensive. Just one other thing, make sure that the blade in the saw is square with the table, the table only has be out slightly and this will create a problem as well.


Phill

First off.... best buy for blades over here without having to add the overseas postage is
Helen Harris [email protected]

Second.. I have been cutting puzzles in all sorts of timber and thicknesses and have never experienced blade breakage like that. I'd almost wonder if the blades are faulty? That does happen sometimes.

I don't like using plywood tho.. the glue in that is very hard on blades. Because I make a lot of puzzles for younger children I like to use a fairly big blade for the 3/4" pine ones... I like #5 or #7 modified geometry from Pegasus. ( yes I buy them from Helen) specially the #7 seems to give a really nice, smooth edge. I like the bigger size because it gives a wider kerf, making it easier for the little ones to put the pieces together, if they have to push hard they sometimes loose interest or might even damage the puzzle which of course causes tears.

One thing... have you tried putting tape - masking tape or something like it on the wood? I use it under the pattern, but you can also just tape it to the bottom of the piece you're working on... that gives a bit of lubrication to the blade and should help keep it cooler, prevents burning too.... might make things easier and who knows.... maybe it will prevent some of the breakage.
Also... when you're done cutting... do your pieces come out either way? can you push them through from either side? If not then you're still pushing too much to one side... that was one of the hardest things for me to learn.. that... or the saw table might not be 100% square....

Good luck
happy scrolling
Juvy