Breaking at the weld

[Karl_N.]

Hello,

If I've had four bandsaw blades, all the same brand, break at the weld after not a lot of use? Is it my mill, the welding or the blade itself? I've thought I've noticed more flutter in the blade and I've read some suggestions regarding flat spots on the rollers that I'll have to look for. I've broken plenty of blades before but never at the weld.
I'm cutting small diameter spruce, it's a bit dry, on a Norwood Lumbermate. 3 years experience.
Thanks in advance.
Karl

[ronwood]

Karl_N

I would contact the manufacturer of the blades. Looks to me that they may have a problem in their manufacturing process.

How long were you able to cut before they broke?

Ron

[Fla._Deadheader]

 We cut a lot of bigger logs, up to 36" wide boards. We have only broken 1 Munks blade. We are on the third and fourth sharpen on some of them. You either have a mechanical problem, or need to try a different brand.

 Flutter is no good. Change the RPM a little at a time, to reduce the harmonic resonance causing the flutter. Going either higher or lower, by 100 RPM can make a big difference in flutter control. Might want to recheck the alignment in the guides, and reduce the tension a little. I know, I know, the experts will say TIGHTEN the tension. All I know is, everything I post about blade problems, comes from what actually did work for us. We use a 24 HP Honda with single belt drive, and I can literally stall the engine. We CAN put extreme pressure on a blade, and the suggestions are from what we found to work on our mill.  Hope some of this helps.  

[smwwoody]

I recently had a problem with a box of new blades I just got from a local supplyer that I usually won't buy from.  He is only 20 miles from me but I still send out for my blades a 1000 miles away to get better quality work.  I needed some bands in a hurry so I went to the local guy to give him one more chance.  the first 2 broke at the weld within about 200 bf each.  over half of the 8 bands left in the box were ground so thin to clean up the weld you could feel a large dip in the band when you slid your fingers over the weld.  I picked up the 2 broken ones and the 8 new ones drove the 20 miles back to his shop and demanded my $312 back and showed him why I havent bought a band off of him in over a year.

Woody

[MrMoo]

Harold,
I have had good luck with the Munks blades too. I haven't broken any and I am on the 3rd & 4th sharpening for them.

[Buzz-sawyer]

Harold& Moo
What did you fellows ever come up with for sharpening the monkeys.....self, others , with what equipment?

[MrMoo]

Buzz,
I sharpen the blades myself. Interesting thing is that the profile of the teeth on the Munks blades matches what the cam dictates on my grinder so it works out pretty well. By the second grinding I am getting well into the gullet. With some other blades I have used they didn't match the cam & it took more grinds to get into the gullet.

I remember a while back (probably several months) there was mention that once resharpened the Munks blades didn't cut straight. They were rising or dipping I can't remember which. I never had that problem. I have good luck with their blades.

Just reread your questions & saw you were asking about equipment. I have the Cooks cat claw setter. The grinder is made by Wright machine. I think I use the C-18 cam (7/8 and 10 degrees).

Mike

[Fla._Deadheader]

Might have been me posting about the Munks rising in the cut after sharpening. I had that problem when I sent them off.

 Got a WM sharpener and do them myself. Had to grind the cam some, to get the gullet. I think the deeper gullet moves the dust better, especially on our super wet stuff. I grind a 13° face for the SYP and Cypress. It really goes through the log quickly, and leaves a smooth face on the boards. Them Cook's and Suffolk grinders is too rich for my blood  

[Tom_Averwater]

MrMoo,
      How do you like the sharpener from Wright Machine ? I'm needing to buy a new sharpener but I just haven't  decided yet on which  one to get.      Tom

[MrMoo]

Tom,
The Wright grinder works well. I like it. Its easy to use and does good job.
My bands are long 19' 1" so I had to go to something different as far as the blade supports. They really were not setup for blades that long. That was the only problem I've had.

If you have shorter bands you won't have a problem. I had sharpened bands from a WM with the original blade supports with no problem at all.
Mike

[Karl_N.]

Hello,

At most, I've gotten 300bf or so out of the four before they broke. It sounds like, unless, I'm out of alignment then it could be the welding job.I don't want to mention the brand name but they've been praised on this forum before so I figure they are reputable. The blades came from a local supplier, I usually get them from a guy in Maine but the mail was too slow for me at the moment. Guess I'm paying for poor planning on my part.  It's frustrating paying the money we do for blades and not have them perform the way they should.
Thanks for the responses.
Karl

[Fla._Deadheader]

We have sawn as much as 1200 ft before changing a blade. Not saying that is a good practice, but, ya gotta do what ya gotta do.

 Have you tried the Munks blades???  Should be able to get a free trial blade if you contact a supplier.  

[Cedarman]

When a blade breaks at the weld, I have been told it is always the welding job. We always save any blade broken at the weld and have always had it replaced for free. One time a blade had two welds on it and the welder forgot to grind the second weld.  Broke the guides on our Baker. The supplier bought me new guides without hesitation once he was sure it was his blade.  Great guy. Blades can be fickle because of variation in the steel  from batch to batch. If anyone wants to know the supplier, I will be happy to let you know.

[D._Frederick]

To get blades that the welds do not break you got to do your home-work. Before buying blades fine out if the person doing the welding has been certified to operate that brand of welder, find out if owner of the welder has a schedule to have the machine factory calibrated.  There is more to welding a blade than meets the eye, the blade needs to be cut a 100% square, the blade needs to be correctly mounted in the welders jaws to assure that it will be straight. The welder needs to be set-up for the correct welding current for the size of the blade and the settings for the tempering and anealing. And finally the weld needs to be dressed.

If they do not do these things, take your business to shops that do.

[sparks]

Breaking after 4 sharpenings is not that uncommon with a few things kept in mind. Remember as the blade rotates it flexs and the gullet begins to crack. Normally these cracks are removed during sharpening if the gullets are being ground and if the cracks are not to long. We've seen 7 to 9 sharpenings before breakage. The bigger the band wheels the better the flex life. We have seen blades come back here that appear to be broken in the weld but when scoped, it is cracked right down the side of the weld. It's hard to take a sharp blade off of the mill but flex life must always be considered over sharpness. After sharpening get a good magnifying glass and periodically check for cracks. May not be your situation but thought I'd give some input.

[D._Frederick]

Sparks,

The cracks by the weld can also be tempering problem.

[DR_Buck]

I've only broken one blade and it was a "Munks" blade.   About 100 bdft and it broke at the weld. Scared the #$:(*&^% out of me when broke!

[sparks]

DF, that's true. The metal where it's welded is the weakest link. The better the steel, the better this area becomes.