Blade Falure

[gkman11]

I have learned that expensive bandsaw blades are usually the best value, given how long they last. I can't say I never abuse one but at over $20.00 each I am pretty careful. I was suprised at the failure of this Starrett from McMaster Carr. It just shed all of its teeth for about 2". A few teeth missing in another spot, otherwise razor sharp. Damage is not at the splice. Any ideas?

[John Stevenson]

Common damage.
What happens is it looses a tooth and jams it in the cut, then the next teeth hit this jammed hardend tooth and rip off as well.
Sometimes a couple of inches go and sometimes a couple off feet go before it rips the jammed tooth out.

I do agree that chaep blades are not worth it.
I personally haven't had much sucess with starrett and use Lenox. About the same price but last longer.
My blades are 12'6" x 1" and cost around £30 UKP each from J&L in the UK
A while ago they were doing Simmonds on off for £26.00 each.
I bought one and it lasted about 2 months wheras a lennox lasts about 6 months on a machine that gets a lot of use.

Sir John.

[mochinist]

I agree with John, as much as I like Starrett products I wasn't impressed with their bandsaw blades, go with Lennox they are way better IMHO.

[JS]

I can not get decent life out of anything , but Starret.

9' 11" 4-6 pitch bades I can get 6 months to a year out of one depending un who is using the saw.


Average is about 8 months.

[Cecil Walker]

Have to agree with John and Mochinist, been using Lenox Diemaster blades on both vertical and horizontal saws for the past 4-5 years. never a problem.

[charlie coghill]

Lennox works for me in my home shop. Two to three years. Fatieg breaks is what kills mine.

[Paul Alciatore]

I had similar damage when I first attempted to cut some of the slotted steel angle. At first I just allowed the blade to fall throuth the slots and when it hit the other side at least a half inch of teeth were stripped off from the shock. Cheap blades, not $20 ones but I bet it would happen to then also. After seeing that I had ruined a blade, I developed the habit of catching the blade when it entered a slot or hole in the angle.

If you allow the blade to drop onto the work, it would likely produce the same result even without the slots/holes in the cut.

Paul A.

[John Stevenson]

Starret stuffed me up big time some years ago.

At the time part of my work was development work and I worked for a company doing portable machine tools for oil field work amongst other machines.
One of the machines they developed was a large bandsaw that clamped onto drill casing rods in the north sea and cut it in two to remove the casing when they were leaving a site.

Capable of cutting 34" pipes with two other pipes and grout inside.
When these are assembled in the field they drop things like gin traps down between the pipes to keep them central whist they pour grout.
For some reason these gin traps are hardened and you have no way of knowing where they are.

They supplied us with a 8' length of pipe with extra traps fitted and marked so we knew where they were.
Initial test were with a Starrett blade 2" wide and 2 tipped teeth to the inch.
After a few problems the machine was done and could cut thru 34" 3 stage pipe in 1 hour and 10 minutes and was shipped off to the north sea fields.

Couple of weeks later got a call to fly out and sort the machine out as it was wandering.
Flew out and yes it was wandering, started off OK and when it was about 3" in the blade went up at about 30 degrees , That's some wander.

Had 10 new blades all the same as the development blade. Tried various adjustments and wrecked 7 blades. Problem was I couldn't fault the machine, tracking was fine, couldn't see a problem.
Had to stay overnight as they wouldn't call a heicopter and missed my flight back.
Wrecked the last three blades the following day and asked again for the machine to be shipped back.

When we got the machine back we had to fit the original blade, now with many mising teeth as it's all we had.
Result it cut perfect, refitted one of the 'new' blades and it just ran uphill.

Got Starrett in and asked what the difference was and they said none but they would make some more blades up at our expense for us to try. We said no we had bought 10 and not had one cut correctly.
Upshot was they wouldn't stand by their product unless we paid up front for everything.

Got in touch with Lennox and they sent a blade FOC to try. Not only did it cut better but they sent two engineers to see it cutting and in the next two weeks sent three more blades, all different.
Result was in three weeks Lennox had the cutting time down from 1 hour to 34 minutes.

These machine now cut perfectly and they had shipped them all over the world.
Here's the link to the machine.
http://www.mirage-machines.co.uk/Pdfs/BS1632.pdf

Not only that but they gave everyone working on the project a couple of die cast hacksaws with a pack of blades.
These frames are the stiffist I have ever come across.
I have now tried Starret, Simmons and Lenox on both by band saws and Lennox wins every time round.

Sir John.

[J Tiers]

I don't think anyopne mentioned the tooth count vs the material thickness (apalogies if I missed it).

If you don't get two teeth on the material at all times, that sort of stripping will happen regularly.

The slotted steel angle is a perfect example. Mostly somewhere around 1mm to 1.25mm thick. If the blade pitch is larger, the teeth can trap the material between two teeth. That means its taking too big a "bite" (trying to take a cut of a whole tooth depth), and probably rips off a tooth, leading to more damage.....

[C. Tate]

I would not reccomend Starret for anything other than metrology equipment.

Make sure you have three teeth in the cut at all times. If you are cutting .5 thickness for example use something like 8-10 or 10-12 pitch. When cutting large sections you want to have very coarse pitch to allow for chip clearence. Cut thin flats standing on edge with fine pitch (at least three teeth in material) if you cut thin sections (something like .125 x 2) lying flat you run risk of filling gullet and causing tooth failure from loading. If you cut thin thin sections lying flat with coarse blade you will find the blade likes to snag in the cut and you have similar problems. Clear as mud.

CT