What's the proper tension for a Resaw King?

[Cliff Polubinsky]

Just picked up an Iturra tension meter. Sent email to Laguna yesterday evening asking what's the proper tension for a Resaw King. Got a reply this morning pointing me to a Laguna youtube where the guy (Laguna employee) says to tension until the blade deflects 1/4".

I replied explaining that I was looking for an actual number and clarified that this was on a 18" Rikon. Her reply was that since it wasn't on a Laguna I should check with my saw manufacturer.

So, does anyone know what the proper tension is for a 1 1/4" Resaw King?

Thanks.
Cliff

[Andrew Hughes]

I use the deflection push on the blade + my gauge that’s on the saw. Never used a tension gadget.
My saw is a 20 inch Aggizani

[John TenEyck]

Carbide tipped bandsaw blades run well at 20 to 25 ksi. I would put 25 ksi on it. If it flutters then lower the tension until it stops.

John

[JOEL MONGEON]

If it flutters then lower the tension until it stops.

John

I'd never heard that before. I thought Carbide tipped blades needed to be extremely tensioned.

I've been struggling with flutter on my Felder FB 510 using a 1" Resaw King blade. I kept tensioning it until the spring was maxed out but the blade kept fluttering. I got so frustrated that I switched back to a regular steel blade that works fine but leaves a rough surface.

[John TenEyck]

I'd never heard that before. I thought Carbide tipped blades needed to be extremely tensioned.

I've been struggling with flutter on my Felder FB 510 using a 1" Resaw King blade. I kept tensioning it until the spring was maxed out but the blade kept fluttering. I got so frustrated that I switched back to a regular steel blade that works fine but leaves a rough surface.

What is it that you never heard before? That you lower the tension to make the flutter stop? That comes straight out of the Grizzly manual for my G0636X bandsaw. You tension to the 1" mark for a 1" blade, which gives a measured 24 ksi on a 1" Lennox Woodmaster CT, probably 25% higher on a Resaw King. Using that as the max, which is arbitrary, but that's how Grizzly goes about it, if the blade runs w/o flutter you leave it there, if it flutters you lower the tension until it stops. That should only reduce the tension 2 or 3 ksi. There's no reason you couldn't increase tension to eliminate the flutter. Flutter is a harmonic vibration related to tension. Change the tension to move away from the frequency that causes the harmonic and flutter stops.

The FB 510 ain't so capable when it comes to tension. 20 ksi might be realistic with a 1" Resaw King, but that should be enough to get reasonable performance, and w/o flutter. Build a tension meter and see what you get. Go from there. Here's the one I built and use with new blades.

https://sites.google.com/view/jteneyck-woodworker/current-projects/bandsaw-blade-tension-meter?authuser=1

John

[Mark e Kessler]

Pretty sure the resaw king should be a lower tension than 20-25k, I think it was designed with the intention to use on the lighter duty bandsaws, i had one on a laguna 14/12 and snapped it on that from over tension and that thing is weak.

[ChrisA Edwards]

Broke my 3/4" Resaw King, last week, on my 14/12. Just had it sharpened by Laguna. Previously, it had been on for 6 years of constant tension, so I can't really complain.

New blade is on and tensioned much lower.

[Mike Wilkins]

I have a Resaw King on my Laguna LT18 and just use the tension gauge on the machine. No problems other than a blade that needs cleaning.

[Jared Sankovich]

Pretty sure the resaw king should be a lower tension than 20-25k, I think it was designed with the intention to use on the lighter duty bandsaws, i had one on a laguna 14/12 and snapped it on that from over tension and that thing is weak.

The rk is thinner than std carbide blades. So 25k on the laguna blade is less force on the saw than 25k on a woodmaster CT. It's all about the blade cross section.a thinner cross section is less force for a given psi target.

[lou Brava]

Have you ran the blade using Lagunas method if so was there a problem ?
I went with Lagunas "vague" tension instructions on a Laguna SUV 14 using a 3/4 resaw king, & a few other blades with great cutting results. Some blade manufactures list the PSI spec for there blades some don't. I tried to research why is knowing what PSI tension on a BS blade is important and never got a good explanation. Laguna isn't concerned with it at all and they sell a lot BS & blades.

[John TenEyck]

Have you ran the blade using Lagunas method if so was there a problem ?
I went with Lagunas "vague" tension instructions on a Laguna SUV 14 using a 3/4 resaw king, & a few other blades with great cutting results. Some blade manufactures list the PSI spec for there blades some don't. I tried to research why is knowing what PSI tension on a BS blade is important and never got a good explanation. Laguna isn't concerned with it at all and they sell a lot BS & blades.

We've talked about this so often here; hard to imagine you missed it. Tension is what allows a bandsaw blade to cut straight and with maximum efficiency - speed. The higher the tension the less tendency there is for the blade to wander and the faster it will cut until the gullets are fully loaded. There should be no debate over that. Will the blade cut straight at lower tension? Yes, to a point, but it will start to wander more easily as soon as it starts to dull on one side, or if it's loaded too fast. What tension should you run at? It's up to you but limited by your saw. Lennox states that their blades are designed to be able to run up to 30 ksi. I run all blades at about 25 ksi on my 17" Grizzly, because it can. On my 14" cast iron Delta I run a 1/2" blade at 12 ksi, because that's all that saw can comfortably muster on a blade that wide. Does it still cut straight? Yes, if it's perfectly set up and I don't push it very hard. But the Grizzly running the same blade at 25 ksi will cut straight even if not set up quite perfectly, much faster, and do it much longer.

John

[JOEL MONGEON]

We've talked about this so often here; hard to imagine you missed it. Tension is what allows a bandsaw blade to cut straight and with maximum efficiency - speed. The higher the tension the less tendency there is for the blade to wander and the faster it will cut until the gullets are fully loaded. There should be no debate over that. Will the blade cut straight at lower tension? Yes, to a point, but it will start to wander more easily as soon as it starts to dull on one side, or if it's loaded too fast. What tension should you run at? It's up to you but limited by your saw. Lennox states that their blades are designed to be able to run up to 30 ksi. I run all blades at about 25 ksi on my 17" Grizzly, because it can. On my 14" cast iron Delta I run a 1/2" blade at 12 ksi, because that's all that saw can comfortably muster on a blade that wide. Does it still cut straight? Yes, if it's perfectly set up and I don't push it very hard. But the Grizzly running the same blade at 25 ksi will cut straight even if not set up quite perfectly, much faster, and do it much longer.

John

That's what I understood from reading books and other posts. What had me confused was the idea of less tension to get rid of flutter. You wrote in one post that you can get rid of flutter if you release the tension on a blade, but then in this last post state that to get a straight cut you must have higher tension.

Anyway, thank you for the earlier reply. I went ahead and bought a tension gauge that should arrive in a few days. I'll be able to set a blade to the right ksi right off the bat without guessing.

"The FB 510 ain't so capable when it comes to tension." I'm not sure what you mean by this. When researching bandsaws last year I did not come across any negative information regarding the Felder machines.

[Erik Loza]

I've been struggling with flutter on my Felder FB 510 using a 1" Resaw King blade. I kept tensioning it until the spring was maxed out but the blade kept fluttering. I got so frustrated that I switched back to a regular steel blade that works fine but leaves a rough surface.

Are both blades identical in length? FB-510 shouldn’t have any problem with that RK.

Erik

[jerry cousins]

i run a 1" resaw king on a mm16 at 29k tension - for many years without any problems
jerry

[JOEL MONGEON]

Are both blades identical in length? FB-510 shouldn’t have any problem with that RK.

Erik

Yes they are both 170", I just rechecked my order.

From R&D bandsaw in Canada: Ripper37 (1" to 1-1/4" wide) - Width: 1" Thickness: 0.032" TPI: 2 Length:170

From Felder Machinery in Canada: RESAW KING BLADE 1in X 170in


The Ripper works well. It cuts very straight but leaves a rough surface. The Resaw King leaves a nice smooth surface but gets a strange flutter and also is leaving some burn marks.
Here are some close ups I took earlier this year with the resaw king blade.
489959 489960

[glenn bradley]

Interesting discussion. Those pics look like they may be the result of an excessive feed rate. I have used the flutter method (see Suffolk's site) on my Resaw Kings since day one. I cut 1/16" veneer between the blade and the fence using minimal tension. More years ago than I can remember I embraced the method of proper setup and alignment of the saw making your blade really want to cut true. I've been riding that horse ever since ;-) I know there are other methods of making a saw cut along the line you want and if those are working for you, keep doing that. There are always more ways than one to skin the cat.

[John TenEyck]

That's what I understood from reading books and other posts. What had me confused was the idea of less tension to get rid of flutter. You wrote in one post that you can get rid of flutter if you release the tension on a blade, but then in this last post state that to get a straight cut you must have higher tension.

Anyway, thank you for the earlier reply. I went ahead and bought a tension gauge that should arrive in a few days. I'll be able to set a blade to the right ksi right off the bat without guessing.

"The FB 510 ain't so capable when it comes to tension." I'm not sure what you mean by this. When researching bandsaws last year I did not come across any negative information regarding the Felder machines.


Joel, I don't think I ever said "release the tension"; more likely I said reduce or decrease. And, yes, higher tension makes it easier to cut straight. Those are not mutually exclusive comments. It doesn't matter if you increase or decrease the tension to stop flutter, the point is to change the frequency so that the blade stops fluttering. There can be several harmonics in the blade, related to different frequencies and different values of tension. Could be at low tension, could be at high tension. In all cases, you decrease or increase tension to stop the flutter.

If you look back through the archives you will find at least one not so favorable review of the FB510 with respect to tension. The author was unable to get 25 ksi on a Woodmaster CT (IIRC) and Felder was of no help in even telling him what the spring constant for the spring in that saw is. That series of posts is what suggested to me that you might be able to get 20 ksi on the thinner Resaw King.

I've been thinking more about your comment that you couldn't get the flutter to go away no matter how much you cranked up the spring, all the way to max. There are only two reasons I can think of for that to be true. One, the spring reaches a point where it no longer adds additional force, or two, the frame of the saw is deflecting disproportional to the added force. If you are fortunate, it's the spring, which can be replaced by an aftermarket one, which I think the author of the other thread did, which, if true, suggests the spring is the problem. One way to prove which is the source of the problem is to install a dial gage between the upper blade guide and table. Also, clamp a set of 6" Vernier calipers to the blade using two small clamps. That will serve as a poor man's tension gage. As you increase the force on the blade, starting at zero, you will see the dial gage compress, ideally very little, but it will. At the same time the calipers reading will increase. If the gap between the jaws of the verniers is 5" at zero spring force, the tension in the blade will be 6 ksi for every 0.001" the gap increases as you increase spring force. Record the reading on the dial gage, verniers, as well as turns on the spring as you increase spring force. Based on your comments you likely will get to a point where the reading on the calipers no longer increases but the reading on the dial gage does. Continue to take measurements as you turn the spring adjuster for another turn or two.

Now take your data and plot spring turns on the X-axis, caliper reading on one Y-axis, and dial gage reading on the other. The slope of both lines should increase nearly linearly up to where the value on the calipers stops increasing. Above that point if the dial gage reading stays constant at higher spring turns then the spring is the problem. However, if the slope of the line for the dial gage gets a lot steeper the problem is the frame. Let's hope it's the spring.

John

[JOEL MONGEON]

Interesting discussion. Those pics look like they may be the result of an excessive feed rate. I have used the flutter method (see Suffolk's site) on my Resaw Kings since day one. I cut 1/16" veneer between the blade and the fence using minimal tension. More years ago than I can remember I embraced the method of proper setup and alignment of the saw making your blade really want to cut true. I've been riding that horse ever since ;-) I know there are other methods of making a saw cut along the line you want and if those are working for you, keep doing that. There are always more ways than one to skin the cat.

Hi Glenn, thanks for that reply. It was the first time I'd heard of the flutter method. Thanks I'll give it a try when I'm back in the shop.

[JOEL MONGEON]

Thanks for the detailed reply John, I should have left it at "less tension" instead of "release the tension".

That is a very good idea. I've got a tension meter on order, it should show up in a few days. I'll try and test if the spring is an issue or at the very least find out how much tension I am applying to my blades. In the meantime I'll try out what Glenn mentioned with the flutter method.

[al ladd]

Reading this I see I use an unusual method of murky provenance (as I can find no mention of this particular method online, though others do talk of blade's musical pitch)that has worked great for me for over 30 years, for a variety of blades on my 20" Davis Wells. I pluck the blade like a guitar string as I tension it, listening for the first additional increment of tensioning that stops producing a discernible raise in pitch. I stop there. This is a noticeable discreet point. Then I do the flutter test, releasing tension if I have flutter (which I almost never do). I get great blade life, wheel bearing life, and resaw results. No tools, no math, but I do have to turn the radio off..... I mostly use 1/2" Trimasters, 1/2" Woodslicers (or its competitors), and 1/4" 4 tpi for tight curves. I do a lot of resawing.....