Bandsaw blade breakage

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jrm688

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I use the EZtension gauge. It’s reasonably priced and easy to use. The centre bolt is set for the blade width using the included jigs. As you tighten the blade one of the magnets pops of when the tension is right.

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Yojevol

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I was suffering multiple fatigue cracks on my Startrite 440R which was fitted from new with ceramic guides. I was concerned that local high temperatures were being generated as evidenced by scorch marks on the guides. Presumably ceramics were fitted because frictional heat was to be expected. I decided to change the guides to a bearing system. I have not experienced any failures since.
Brian
 

Spectric

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I think the clue is in the fact you "tension" a bandsaw blade, ok this is done by applying a force but it is the stretch, blade CSA and the modulus of the blade steel that will tell you tension and as force is Newtons, and stretch in metres the result will be Newton metres not force over area. Yes the stretch will be a very small number in metres so perhaps Newton mm if there is such a thing.
 

pe2dave

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From the above it would seem that those with 'big' (1" +?) blades are bothered?
For (a majority?) using lesser sized blades, is 'about that' good enough?

The confusion over metrology is ... confusing. ;-)
Tension (lengthways) torque (twisting) torsion (twisting).
 

TheTiddles

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From the above it would seem that those with 'big' (1" +?) blades are bothered?
For (a majority?) using lesser sized blades, is 'about that' good enough?

The confusion over metrology is ... confusing. ;-)
Tension (lengthways) torque (twisting) torsion (twisting).

I’m sure we are all thinking of Daniel Oppenheimer’s paper on the consequences of erudite vernacular utilised irrespective of necessity :)
 

Ttrees

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From the above it would seem that those with 'big' (1" +?) blades are bothered?
For (a majority?) using lesser sized blades, is 'about that' good enough?
A lesser sized blade, what might be honestly suitable for a machine which won't compress the spring fully, likely is getting past 15K PSI from what I can make out.
From John's comment I'm guessing the difference between an adequate 15+K PSI or whatever it should be for easy work, and 25K for resawing
could be a very small adjustment on any suitable blade.

So for the majority who wants to rip or resaw, which I admit might not be the same as the majority of bandsaw users...

Those who don't stick a 1" or 3/4" blade on a mid sized machine,
(even though the manufacturer states is suitable)
and choose 1/2" or whatever instead.. which won't bottom out the spring,
"about that" might be closer to 25k than one might think.

Applicable for anyone who is pushing the limits on smaller machines,
which if going by most of the well known bandsaw publications in the last 30 years on the matter, most which opt for a blade which might seem to some, a tad small for the machine.

Bearing in mind that one resawing veneers maybe concerned with the timber as much as the blade, and be a bit braver when tensioning it.
 

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