blades breaking - Scroll Saw Woodworking & Crafts Message Board

Ralph Sayward · 07-04-2009, 01:15 AM

I realize that scroll saw blades do not last long when they are only .011 thick (cutting puzzles) my question is - most of my blades break just above the bottom clamp - is this normal or this is a clue that my pressure is not right (either too tight or too loose )any advice would be appreciated - Ralph

Ugsduck · 07-04-2009, 04:16 AM

Maybe the blade isnt going into the bottom clamp properly and is creating a bend near the clamp?

smw6442 · 07-04-2009, 04:33 AM

Hi Ralph, i'm not an expert on this subject. but what i've been told by reading on this message board that when blades brake means you might have to much tension on the blade or your speed is to fast for the type of blade your using. try turning down the speed of the saw and put less tension on....on the bottom clamp check and see if the screw you use to tighten the blade is flat sometimes there not and can make it so your blade wont tighten down.. i hope this helps these are just things someone told me before on the message board.. steve

mrcutit · 07-04-2009, 09:13 AM

DIDDO all of the above, also watch how much preasure you are putting on the wood, let the blades do the work.

unixpro · 07-05-2009, 01:47 AM

Make sure that the top and bottom blade holders are lined up with each other.

Marsha · 07-05-2009, 03:02 AM

Quote:

Originally Posted by smw6442

Hi Ralph, i'm not an expert on this subject. but what i've been told by reading on this message board that when blades brake means you might have to much tension on the blade or your speed is to fast for the type of blade your using. try turning down the speed of the saw and put less tension on....on the bottom clamp check and see if the screw you use to tighten the blade is flat sometimes there not and can make it so your blade wont tighten down.. i hope this helps these are just things someone told me before on the message board.. steve

I totally disagree with this statement.
The number one reason for blade breakage is Not Enough Tension. When the blade is not tensioned enough it will flex, and catch in the kerf thus causing the breakage.
Marsha

miniwoodworker · 07-05-2009, 12:23 PM

Agree. IMHO, it's far better to have too much tension than not enough. Not enough will automatically allow the blade to flex. Just like removing a pop top from a soda can. Flex it a few times and it'll break right off.

Also agree to simply let the saw cut. Forcing the wood into the blade, especially when it starts to dull, puts extra stress on the blade.

Mick Walker · 07-05-2009, 03:15 PM

I agree with Marsha and Lee. I have never had a blade break because there was too much tension on it. Too much tension will usually cause the blade to slip out of the clamp. Twisting or side pressure will cause the blade to break. Blades that are dull will get hot and break.
Ralph, does your blade break below the table or above? Breaking below the table is most likely a clamping problem, above the table is a twisting of the blade or you are pushing sideways on the blade. Push the wood straight into the teeth, if the blade is dull you will have to push harder causing the blade to bow to the backside.

CallMeTut · 07-05-2009, 03:43 PM

I have the same problem as Ralph, a lot of breaking blades using the RBI (220). When I used a Dewalt I never had a problem. My blade breakage is also on the bottom, normally under the tabletop. With the RBI you use a "clock code" for tensioning, for 2/0 and 1 spirals I'm setting at about 12:30 and getting a good "ping" if plucked.
I've even ran the saw without cutting anything after about 5 minutes the blade broke... new blade, never touched the sides of the hole in the table, blade was straight in the holders and if viewed looking down the length there is no wobble.
I use to cut forever with a blade using the Dewalt...

unixpro · 07-05-2009, 05:07 PM

That still sounds to me like a mechanical problem with the way the blade is being held. I agree that poor tension isn't generally an issue -- I go as far as I can every time.

Tutor, if you put in a straight (not spiral) blade and run it without load, does that break, or is it only with the spirals? If it happens with the straight blades, what happens if you stop the saw after 4 minutes? Is the blade twisted at all? Is there any discoloration near the bottom of the blade? Either of these would indicate that the blade is being horked (that's a technical term) around in the holder. The bad news is that you'll probably have to take or send the saw in for service.

Blades break because of fatigue. The fatigue can be induced by the blade twisting one way or another while it's being used. If the two holders aren't lined up correctly, you'll be bending the blade as it enters the wood from the bottom. You'll also see burning on the bottom part of the cut in this case. Another reason can be twisting, which happens if the holders aren't coming from the arms at a perfect angle, or if they're loose, allowing the blade to flop (another technical term) around in the cut. The only real indication here is that you'll find it very difficult to get clean, tight cuts, especially with a new, sharp blade.

07-04-2009, 01:15 AM	#1
Ralph Sayward Junior Member Join Date: Apr 2009 Posts: 3	blades breaking I realize that scroll saw blades do not last long when they are only .011 thick (cutting puzzles) my question is - most of my blades break just above the bottom clamp - is this normal or this is a clue that my pressure is not right (either too tight or too loose )any advice would be appreciated - Ralph

07-05-2009, 12:23 PM	#7
miniwoodworker Senior Member Join Date: May 2005 Posts: 496	Agree. IMHO, it's far better to have too much tension than not enough. Not enough will automatically allow the blade to flex. Just like removing a pop top from a soda can. Flex it a few times and it'll break right off. Also agree to simply let the saw cut. Forcing the wood into the blade, especially when it starts to dull, puts extra stress on the blade. __________________ Lee in NC Als Ik Kan DW788 1975 Dremel (labeled Craftsman) Scroll saw w/3" pin blades

07-05-2009, 03:15 PM	#8
Mick Walker Senior Member Join Date: Jan 2005 Location: Janesville, WI Posts: 1,660	I agree with Marsha and Lee. I have never had a blade break because there was too much tension on it. Too much tension will usually cause the blade to slip out of the clamp. Twisting or side pressure will cause the blade to break. Blades that are dull will get hot and break. Ralph, does your blade break below the table or above? Breaking below the table is most likely a clamping problem, above the table is a twisting of the blade or you are pushing sideways on the blade. Push the wood straight into the teeth, if the blade is dull you will have to push harder causing the blade to bow to the backside. __________________ Mick, - Delta P-20 The future ain't what it used to be.

07-05-2009, 03:43 PM	#9
CallMeTut Senior Member Join Date: Nov 2008 Location: Misery (Missouri) Posts: 100	I have the same problem as Ralph, a lot of breaking blades using the RBI (220). When I used a Dewalt I never had a problem. My blade breakage is also on the bottom, normally under the tabletop. With the RBI you use a "clock code" for tensioning, for 2/0 and 1 spirals I'm setting at about 12:30 and getting a good "ping" if plucked. I've even ran the saw without cutting anything after about 5 minutes the blade broke... new blade, never touched the sides of the hole in the table, blade was straight in the holders and if viewed looking down the length there is no wobble. I use to cut forever with a blade using the Dewalt... __________________ Tutor --------------------------------- Pattern design tutorial at ScrollsawPortraits.com Come to the darkside... use spirals...

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07-04-2009, 04:16 AM	#2
Ugsduck Junior Member Join Date: Jun 2009 Posts: 29	Maybe the blade isnt going into the bottom clamp properly and is creating a bend near the clamp?

07-04-2009, 04:33 AM	#3
smw6442 Member Join Date: Nov 2008 Posts: 45	Hi Ralph, i'm not an expert on this subject. but what i've been told by reading on this message board that when blades brake means you might have to much tension on the blade or your speed is to fast for the type of blade your using. try turning down the speed of the saw and put less tension on....on the bottom clamp check and see if the screw you use to tighten the blade is flat sometimes there not and can make it so your blade wont tighten down.. i hope this helps these are just things someone told me before on the message board.. steve

07-04-2009, 09:13 AM	#4
mrcutit Senior Member Join Date: Mar 2008 Location: Marrero Louisiana Posts: 290	DIDDO all of the above, also watch how much preasure you are putting on the wood, let the blades do the work.

07-05-2009, 01:47 AM	#5
unixpro I need more weekend Join Date: Dec 2006 Location: Greater Seattle Area Posts: 713	Make sure that the top and bottom blade holders are lined up with each other.

07-05-2009, 05:07 PM	#10
unixpro I need more weekend Join Date: Dec 2006 Location: Greater Seattle Area Posts: 713	That still sounds to me like a mechanical problem with the way the blade is being held. I agree that poor tension isn't generally an issue -- I go as far as I can every time. Tutor, if you put in a straight (not spiral) blade and run it without load, does that break, or is it only with the spirals? If it happens with the straight blades, what happens if you stop the saw after 4 minutes? Is the blade twisted at all? Is there any discoloration near the bottom of the blade? Either of these would indicate that the blade is being horked (that's a technical term) around in the holder. The bad news is that you'll probably have to take or send the saw in for service. Blades break because of fatigue. The fatigue can be induced by the blade twisting one way or another while it's being used. If the two holders aren't lined up correctly, you'll be bending the blade as it enters the wood from the bottom. You'll also see burning on the bottom part of the cut in this case. Another reason can be twisting, which happens if the holders aren't coming from the arms at a perfect angle, or if they're loose, allowing the blade to flop (another technical term) around in the cut. The only real indication here is that you'll find it very difficult to get clean, tight cuts, especially with a new, sharp blade.