BANDSAW TENSION SPRING
#17
(12-03-2019, 07:08 AM)EvilTwin Wrote: I never detension the blades on either of my saws, a 20" Delta and 10" Inca.  Never had an issue from it with out of round tires or stretched blades.  Ben at it for well over 30 years on a few different saws.   I know some folks believe in it and there are some fancy aftermarket addons to make it easy to do, but to me its a fix in search of a problem.
A recent survey showed that those who detension are 50% more likely to ground their PVC DC pipe....
Better to follow the leader than the pack. Less to step in.
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#18
(12-03-2019, 09:08 AM)MichaelMouse Wrote: A recent survey showed that those who detension are 50% more likely to ground their PVC DC pipe....

Livin dangerously I am on more than one count.
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#19
Many thanks for everyone's comments.  They were very much appreciated.

I tried contacting Carter products.  They had nothing that would work on my saw.  I got another spring from Rikon and the problem still exists.  I don't know where else to look.  But I also thought about getting a shorter blade to see if that would make a difference.  Going to try that next.  I guess I'll just have to live with it.

Thanks again, everyone.  

Ray
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#20
(12-04-2019, 02:09 PM)falcon Wrote: Many thanks for everyone's comments.  They were very much appreciated.

I tried contacting Carter products.  They had nothing that would work on my saw.  I got another spring from Rikon and the problem still exists.  I don't know where else to look.  But I also thought about getting a shorter blade to see if that would make a difference.  Going to try that next.  I guess I'll just have to live with it.

Thanks again, everyone.  

Ray

If you have a 1/2 x 0.025 x 3 tpi blade the cross sectional area in the gullet is about 0.0095 sq. in.  For 10 ksi tension on the blade the spring needs to apply a force of 95 lbs.  You can easily check to see if the spring is capable of doing that.  Take it out and see if you can apply 95 lbs, or more, force to it on a bathroom scale before the coils collapse.  

Another way to go about it is to take the tension to zero (or just enough tension to be sure there's no slack).  Then clamp a set of Vernier calipers on the blade with two little C-clamps.  Set the jaws of the Vernier at about 5" before clamping the jaws.  Now crank up the tension.  For every 10 ksi of tension the blade, any blade, will stretch 0.0017".  

John
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#21
Can you see the spring in that saw when it is under tension? Are the coils bottoming out? Use a thin feeler gauge to check. If they are you need a stiffer spring. I understand you are having a hard time finding one. Thinner and narrower blades need less tension. Are you using an appropiate blade for your saw and these tests?
If the coils are still doing their job and an appropriate blade is in use then it is time to look at the tension system or a shorter blade if the tension system is reaching its limits. 
If the spring is not bottoming out and the tension system is doing its job of raising the wheel you could have an issue with your frame flexing more than it should. 
When you see hoof tracks think horses before zebras. In this case the frame having an issue would be a zebra. Look at everything else first.
Proud maker of large quantities of sawdust......oh, and the occasional project!
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#22
(12-03-2019, 09:08 AM)MichaelMouse Wrote: A recent survey showed that those who detension are 50% more likely to ground their PVC DC pipe....

According to my old science teacher, 71% of all statistics are made up on the spot to support an opinion. Yours, of course, is part of the 29%.
We do segmented turning, not because it is easy, but because it is hard.
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