From: [email protected] <[email protected]> On Behalf Of Mark
Sent: Thursday, October 28, 2021 6:09 AM
To: [email protected]
Subject: [ExternalEmail] Re: [4x6bandsaw] Band saw blade tension

?

On Thu, Oct 28, 2021 at 02:23 AM, John Vreede wrote:

The correct stress is 15000psi min / 20000psi?max for carbon steel blades and 20000psi min / 25000psi max for bimetal blades..

John,?

Excellent explanation. Thanks

I had no idea they made a spoke gauge. "You stated the correct tension is higher than you might think" and I agree. It needs to have a lot of tension. The strength of the blade under straight tension is significant but weakens significantly if deflected and it also fatigues the metal in the blade over time. Of course a deflecting blade doesn't cut as straight either.?

So get this...? My HF band saw frame starts to deflect significantly under high tension. In fact this is how I set my tension, I watch for deflection and stop at about 1/8" or a bit less. My first thought is, this deflection could be made into a tension gauge but my second thought is, how in the heck did you ever get enough tension to break blades or shorten blade life. So far I have never had a blade break, at least not after I aligned everything and set it up correctly. I've been running the same blade for 7 month now. I know that's not a good indicator in itself but I can say it has cut a lot of metal and I suspect it will be dull before it ever breaks.?

Also 17,000 PSI seems extreme and higher than the saw is capable of. PSI - Pounds per square inch? Square inch of what? Are you saying this force on the blade would be the same as hanging a 17,000 lb weight on the blade? Or maybe half this amount seeing as how you are tensioning two halves of the same blade? Still, even 8500 lb seems extreme.

I'm not doubting your information, I'm just looking for clarity.? And thanks for the info.

Mark

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