Band saw tension spring

[falcon]

I have a Rikon 14" bandsaw that I think needs a new blade tension spring.  I detention the blade whenever I leave the shop for the day and re-tension it again when I'm ready to use it again.  For the past few weeks, I have had to increase the tension more and more with each use to get the blade to the proper tension.  I wrote to the Rikon tech service and even called the tech guru but I got no response.  I asked the Carter folks about getting a new spring but they told me that they don't make a spring for the Rikon 14" bandsaw.  

What's the deal with the "yellow" Cobra spring that is supposed to fit "most" 14" bandsaws?  Has anyone replaced their original blade tension spring with one of these Cobra springs?  And if you did, how was it to change it out and how is it working out for you?

Thanks for any comments.

Ray

[woodhead]

I did use one on my Grizzly G0555. I had distorted the original spring. Much heavier and works well.  The cobra solved my problem


Al

[jteneyck]

I have a Rikon 14" bandsaw that I think needs a new blade tension spring.  I detention the blade whenever I leave the shop for the day and re-tension it again when I'm ready to use it again.  For the past few weeks, I have had to increase the tension more and more with each use to get the blade to the proper tension.  I wrote to the Rikon tech service and even called the tech guru but I got no response.  I asked the Carter folks about getting a new spring but they told me that they don't make a spring for the Rikon 14" bandsaw.  

What's the deal with the "yellow" Cobra spring that is supposed to fit "most" 14" bandsaws?  Has anyone replaced their original blade tension spring with one of these Cobra springs?  And if you did, how was it to change it out and how is it working out for you?

Thanks for any comments.

Ray

Springs don't usually lose tension unless stretched/compressed beyond their rated length limit.  What led you to conclude the spring is not giving adequate tension?  Are you actually measuring it?  

I have a yellow spring on my 14" Delta that I got from Iturra.  It does what it's supposed to.  It was an easy change out.  

John

[falcon]

Springs don't usually lose tension unless stretched/compressed beyond their rated length limit.  What led you to conclude the spring is not giving adequate tension?  Are you actually measuring it?  

I have a yellow spring on my 14" Delta that I got from Iturra.  It does what it's supposed to.  It was an easy change out.  

John

I can't get the tension needed to get a good resaw.  I could for awhile, but now I have to increase the tension a little more each time I use the saw.  I realize that blades may stretch a little, but this is way too much stretch, in my opinion.  I just can't get enough tension to keep the blade from drifting.  And it doesn't really tighten the blade, any blade, the way it did when it was new.

Ray

[woodhead]

The Cobra is a robust spring compaired to the original.


Al

[jteneyck]

I can't get the tension needed to get a good resaw.  I could for awhile, but now I have to increase the tension a little more each time I use the saw.  I realize that blades may stretch a little, but this is way too much stretch, in my opinion.  I just can't get enough tension to keep the blade from drifting.  And it doesn't really tighten the blade, any blade, the way it did when it was new.

Ray

It could be the spring, but it could be a dull blade.  The only real way to know how much tension is on the blade is to measure it.  It's not hard to do.  With barely any tension on the blade, open a set of 6" digital Vernier calipers to 5" and clamp them onto the blade with two little C-clamps, like this. 




Write down the exact reading on the display, then reset it to zero.  Now crank up the tension.  For every 0.001" you observe on the Vernier display the tension in the blade is about 6,000 psi.  This is independent of blade type or width.  My 14" cast iron Delta shown in the photo above cannot practically apply more than about 12 - 14,000 psi on a 1/2" blade (more on a narrower blade, less on a wider), regardless of what spring is in it.  The good news is it will resaw and slice veneer just fine, straight and true, with a sharp blade and everything set up well.  The bad news is the speed is really slow.  

In practical terms it's hard to set the verniers to exactly 5.000".  That's why you wrote down exact value before you rezeroed it.  This simple calculation will give you blade tension.

Tension (psi) = 30,000,000 x display/X, where X = the value you wrote down before rezeroing the display.   The 30,000,000 psi value is the Young's Modulus of steel.  If you know the value for the blade you are using substitute that value instead.  

John

[falcon]

It could be the spring, but it could be a dull blade.  The only real way to know how much tension is on the blade is to measure it.  It's not hard to do.  With barely any tension on the blade, open a set of 6" digital Vernier calipers to 5" and clamp them onto the blade with two little C-clamps, like this. 




Write down the exact reading on the display, then reset it to zero.  Now crank up the tension.  For every 0.001" you observe on the Vernier display the tension in the blade is about 6,000 psi.  This is independent of blade type or width.  My 14" cast iron Delta shown in the photo above cannot practically apply more than about 12 - 14,000 psi on a 1/2" blade (more on a narrower blade, less on a wider), regardless of what spring is in it.  The good news is it will resaw and slice veneer just fine, straight and true, with a sharp blade and everything set up well.  The bad news is the speed is really slow.  

In practical terms it's hard to set the verniers to exactly 5.000".  That's why you wrote down exact value before you rezeroed it.  This simple calculation will give you blade tension.

Tension (psi) = 30,000,000 x display/X, where X = the value you wrote down before rezeroing the display.   The 30,000,000 psi value is the Young's Modulus of steel.  If you know the value for the blade you are using substitute that value instead.  

John

Great information, John.  Thanks.  I'll give it a try.  I realize the blade has to be sharp too.  I don't believe its dull as I haven't used it all that much since I installed it.  It's a 1/2" woodslicer blade and it worked flawlessly for a couple of resaws in red oak.  But, I suppose I could get a new blade and see.  Thanks again for the information.

Ray

[fredhargis]

Be aware that a common criticism of the Woodslicer is how quickly it looses it edge(s). I can't say that's been my experience, but I don't resaw as much as a lot of others. Something to keep in mind.

[jteneyck]

Be aware that a common criticism of the Woodslicer is how quickly it looses it edge(s). I can't say that's been my experience, but I don't resaw as much as a lot of others. Something to keep in mind.

Yep, I'm one of them.  I got about 2 or 3 nice resawn pieces out of a Woodslicer in some hard maple; pieces maybe 10"w x 2 or 3' long.  Then it started acting all wonky and I could not get it to cut straight again.  Put a bi-metal blade back on and things were fine.  Never tried Woodslicer again.  

John

[falcon]

Yep, I'm one of them.  I got about 2 or 3 nice resawn pieces out of a Woodslicer in some hard maple; pieces maybe 10"w x 2 or 3' long.  Then it started acting all wonky and I could not get it to cut straight again.  Put a bi-metal blade back on and things were fine.  Never tried Woodslicer again.  

John

I see.  Maybe that's the case.  Thanks for the insight, everyone.  And since you have provided that bit of information, what is your recommendation for a good resaw blade?  I don't do much of it, but when I do, I would like for it to go well.

Ray