Broken Blades

[ChuckD]

I am not a new scroller, been around for a while. Long enough to pick up a bad habit. Don't know what it is tho. On both of my scrollsaws, a Hegner and a Delta P-20, I break blades right at where the blades goes into the bottom clamp. I thought it might be because I tighten them to much but even the slightest bit less the blades comes out. Then, I thought I am pushing the blade to hard but I did the test of stopping and letting the blade "catch up" and that proved that was not the answer. More an agravation than anything else, having to replace the blade when it is still good. I kept the blades for a long time incase someone needed a blade that was a quarter inch shorter but the stack got to high
Any ideas from the experts???

[SharonW0111]

Chuck- maybe it could be a simple thing like getting your tension to tight or the screw clamp on your insert has a bur on it. I have a Craftsman and there is a set screw and a clamp screw on the clamps - this is to keep the blades sqauare - and the set screw was off and all I had to do was adjust this and flatten the clamp screw ( sandpaper workks well) and waalaaa no more broken blades - Maybe this will help you

Sharon

ps -- i am no expert but just a friend trying to help

[Thomp]

I just recieved a SS250 delta rom my brother, he got it a few years ago and never used it for anything,

When i finely got it all reassembled from shipping. i set in a blade in the bottom clamp and tightened it like any other, noticing it was leaning forward a lot..
finely figured out the dofference between delta and dremel blade clamp system after i chased the little spring around the porch,

never the less i soon went through 2 blades like you mentioned.
snapped right at the bottom clamp...

my problem was i had been putting the blade in ar an angle not 90 degreese to the blade clamp.
upon further investigation, of the broken blades, i noticed it looked bent away from the teeth, on the backside..

after i took care to insure the blade was properly in the clamp i havent had a problem, been cutting 2x4 and 2x6 wood all day today... slow but it works fine.

[ChuckD]

Thanks Thomp, that discribes my problem, with the bent blade. How do you manage to get the blades in at a 90 degree all the time? Mine doesn't want to go there and I just replaced the clamp.

[Thomp]

I dont know on your saw, but on this delta there is a key that pinns the bottom clamp swivel in place so you cant twist the lower swivle as you tork the set screw when tightining.
with this funny werench of sorts its a delta thing.
it has the one pin that allignes through the swivle and the lower arm and then it has a allen wrench next beside the pin hooked up all on this weird wrench..

I was presuming that the clamp was being pinned at 90 degreese. but something is bent or weird and the blade if you clamp it without actualy eyeballing and alligning the blade sets at about 50 degreese or so, and tighting the top clamp and adding tention trys to bend the blade to 90 degreese between the clamps.
I just use a small flashlight to peek under the dust sheild and view the correct allignment. on the bottom clamp..
.

[SharonW0111]

Chuck --may I butt in here for a second?
I have a Craftsman and my bottom blade holder is on a swivel pin. But Thomp is right about getting the blade in straight- I use a pair of hemastats (locking scissor type things that grab hold and lock ) to hold my blade in place while I use both hands to tighten my blade holder on bottom. One hand holds the holder up like it should be and the other hand screws the set screw. After that is done I remove the hemastats and then thread the top-- Idon't have to remove the bottom blade again until it is time to change blades.
Sharon

[Mick Walker]

ChuckD, Thomp's Delta 250 has a different clamp than your P-20. I have the P-20 and have never had a problem breaking blades at the lower clamp, I top feed so am using the bottom clamp a lot. I always make sure that the bottom clamp is straight up and down when I lock the blade in. I can see where if the clamp is tipped forward or back you would be putting stress on the blade. I usually use a tiny 2/0 blade and will break it if I try to use it too long and it gets dull and probably gets hot. Don't know if this will help or not. Have been scrolling for 14 years and still jump when a blade breaks. Mick.

[ChuckD]

Thanks guys and gals for the info. I do have the P-20 so it is toolless connection, just pulll a lever and it tightens the blade. The angle may be the problem but why would that happen on my Hegner? the bottom of the blade is clamped before I put it back on the saw. (Bottom feed, the reason I bought the P-20). Blades on both break at the same spot. I hate mysteries.

[BobD]

Chuck,
I noticed the same thing with the Hegner we have in the office...The blade clamps on the bottom are something else...

I noticed that there was a burr developing at the top point of that triangle that clamps the blade...and my blades were breaking there. I came to the conclusion that the burr was scoring the blades, weakening them, and causing them to break there. I also noticed with the Hegner that if you don't have the blade exactly centered on that Triangle, it breaks easier. i notice it a lot more with fine blades, such as #2/0, than with bigger blades...then again, i break so many of the little blades that it doesn't matter what I do <grin>

Bob