Do you use a bandsaw blade tension gauge?

[Randall J Cox]

I have two bandsaws, an old Delta 10" with a 1/4" blade that I rebuilt and an older MiniMax S45 18" (green) with a 1/2" Lenox Diemaster II. Tried doing some resaw the other day on the 18" and got the barrel results on the last 1/3 of the board. Thought I had it tensioned somewhat correctly using the flutter method. I'm forever guessing at tension based on results and other methods. I don't do much resawing but it would be nice to be able to do it now and then. I've probably read most of the articles on bandsaws floating around on this forum and OWWM forum over the past 5 years.
How many out there find it worth the cost to buy and use a blade tension gauge? Looking at Itura Design for about $225. Randy

[Andrew Seemann]

I don't have one. Actually, I've never seen one in any of the shops I've been in.

[Bruce Page]

I had a nice Starrett 682 tension gauge that I sold to someone here on the forum. I never used it much. I tension using the flutter method. It’s quick & easy and it works well for me on my MM16.

[Mike Cutler]

I don't use one.

I tested a bunch of them, by three different manufacturers, for Mark Duginske many years ago, just after his second band saw book came out. I didn't find any of them repeatable, or reliable. The only one I would have used was the electronic Carter tension gauge that read out in lbs./wheel force. It's discontinued now, but for the 14" Delta and clones, it was a nice setup.

[jerry cousins]

i have an iturra gauge that i use when putting on a new blade on my mm16 - older generation - or if i have taken off the blade for some kind of fix-it and then reinstalling. the saw is only used for resawing veneers. i tighten a 1" resaw king to 2900 pounds. when i'm done cutting i back off the tension wheel 2 complete turns - and the re-tighten for the next use.

i also have a 14" delta bandsaw used for smaller things and curves - but have never used the gauge on that one - just crank it up a little past the saw's tension spring for that size blade - and do not de-tension it between cuts.
jerry

[Mike Kees]

There have been multiple posts on how to make a tension gauge way cheaper than buying one. John White has a simple design in his book "Care and repair of shop machines" that should help. I have a tension gauge that I bought off a guy on the 'bay" who machined them . The hard part of tensioning is getting guidelines of what the tension should actually be at for a specific blade size/thickness. I found it most helpful in figuring out what my machines were capable of delivering tension wise. I do still use it on my larger saw when replacing a blade.

[Randy Heinemann]

I have never used a blade tension gauge. Based on all articles I've read over the years, both for and against, I could never see that using a gauge would yield better results than just assessing the tension by pushing with your finger to determine the blade's deflection. In additon, I've seen Alex Snodgrass demonstration blade installation and bandsaw tuneup at a number of woodworking shows and on YouTube. Based on his method, which is using his finger to deflect the blade, I can't see the value of a blade tensioning gauge. If you don't feel the blade has enough tension based on your resawing results, just gradually put more tension on until you feel it gives you the result you want (although I doubt that the tension is usually the cause of resawing problems). There is obviously a limit to how much tension you can put on a blade, but I think that blade breakage from too much tension is rare. At least it's never happened to me.

[David Kumm]

I've had four over the years and all were repeatable which is more important than accurate. Iturra had some problems with indicators years ago when Mark Duginske tested them and they got a bad rap. I had one and Louis replaced the gauge and problems were over. I used to put three on my 36" saw and they all measured with 1000 of each other so they do work. Spending even $200+ on a used one for your application is a close call. Probably a home made one or even borrowing one will be enough for what you need. When buying 200+" Trimasters at several hundred dollars each and using multiple saws, it pays to have some accuracy when setting expensive blades. It does take more tension than you think to resaw with small blades. The SCM is light frame saw ( not like their Centauro machines ) and the Delta is too small to really benefit from a meter. I'd save the money for something else and just keep cranking until the spring gets close to bottoming and see what happens. Dave

[Ken Fitzgerald]

I don't have or use one. Like others, the flutter method has worked well for me.

[John TenEyck]

For less than $25 you can build a blade tension meter in an hour that is repeatable and as accurate as commercial units. Using one will:

1. let you know how much tension your saw is capable of applying to any particular blade.

2. tell you whether your saw actually can tension the widest blade the manufacturer claims it can. Many can't, even some with expensive logos on them.

3. let you set the tension of any particular blade for optimum performance. I want to know what the tension is in a $150 blade, not guess at it. I don't want to run it with the tension too low and risk premature failure. Nor do I want to run the tension too high and risk damaging my bandsaw, which is a real concern on my little Delta 14" and I suspect many other machines.

4. allow you to figure out what the correlation is between the tension pointer on your saw with actual tension in any particular blade. The flutter method works fairly well IF the spring in the saw applies 20 ksi or more to a blade where the pointer should be for that blade. But many springs are woefully inadequate yet you can still get flutter near where the pointer should be. It's an unreliable indicator of tension without verification. Same with side deflection. My interpretation of 1/4 or 1/2" side deflection is different than yours.

5. eliminate doubt. If you know a blade has the right tension on it but then starts barrel cutting that something is wrong with it.

John

[Frederick Skelly]

For less than $25 you can build a blade tension meter in an hour that is repeatable and as accurate as commercial units. Using one will:

1. let you know how much tension your saw is capable of applying to any particular blade.

2. tell you whether your saw actually can tension the widest blade the manufacturer claims it can. Many can't, even some with expensive logos on them.

3. let you set the tension of any particular blade for optimum performance. I want to know what the tension is in a $150 blade, not guess at it. I don't want to run it with the tension too low and risk premature failure. Nor do I want to run the tension too high and risk damaging my bandsaw, which is a real concern on my little Delta 14" and I suspect many other machines.

4. allow you to figure out what the correlation is between the tension pointer on your saw with actual tension in any particular blade. The flutter method works fairly well IF the spring in the saw applies 20 ksi or more to a blade where the pointer should be for that blade. But many springs are woefully inadequate yet you can still get flutter near where the pointer should be. It's an unreliable indicator of tension without verification. Same with side deflection. My interpretation of 1/4 or 1/2" side deflection is different than yours.

5. eliminate doubt. If you know a blade has the right tension on it but then starts barrel cutting that something is wrong with it.

John

Which plan did you use John? Would you mind sharing? It would be a fun afternoon project.
Thanks.
Fred

[Andrew Hughes]

I don’t use them either. A new sharp blade solves all my bandsaw problems.
I have a 14 pm and a 20 inch Aggi.

[John TenEyck]

Which plan did you use John? Would you mind sharing? It would be a fun afternoon project.
Thanks.
Fred



I followed the design I saw on a YouTube video; sorry, can't remember for sure which it was. But it's so simple these photos should be sufficient. Here are the parts:

https://lh3.googleusercontent.com/rdU4Yw4i1qhZ9fnAG5A8jkkzE5FAcZuFE93Wr0bP0craocU4tZ Ok5RivH1ii4CUn6ShcQb84c_aACMYNC_sB0hMgw1YpCR8Ss5m1 cWB0FzOyxgwWtzmOvjnJHfY821Gxf9ZEoMiylLojoO_nJQS08-Bp3bamJVHvg6rOYYfnpmQZwu9vl39ZL9TvasQvI6DsP-RS52jmtAgu30qlkc4X3Wqtk_CzEEk0bYURc-7Yd4LshAli1BttI2PU7Zymgsej3GLYhX90SyftwolQ2L5dwCjo lGE07XQUyvxfA6S3vGjorNuWaBTfvQlM4GVqeNTLmxPc4L-J6BMpXPQjimKMPd_SeV9Mgn3Royxplc6KzNW880L0GYYW9dSrR A1OpU-QiJ6o3Rmf-FbARnPa8V0qe4T8hXeek-C5a4l6YCJf5-zoauZCAz04bFEZn2ZdLQg0OXH0jvoG5iLdgrCUzvp6rKfomtU3 LP0llzEpaDfUzs414pI45qjQPwe3KVLxXBlI1fMdgKcPcvr5bU jPc9tCji6JpJry-zamkCwPp8q-thnd96MdvRzz5YX0sMgVhLY94QE3Ks-_hRKcmBJEhMaJTJpTB4iy6H06tqSenpDI7m2QEmkBF8tdm9skF c4kTg6maXp1QEY8Ij0dMo-z9eO5jBWaJDuTLrWej4gXL3zajq-L-mTFkvl8iD31Bp_oKwbzUhy1OKY_bCQCAbTZWxDRkxDmbe5SOWz Kvwn2o9nOEpf-g5Q67A=w835-h626-no


The upper two pieces of wood are doweled and glued together. The dowel in the lower piece slides into an oversized hole in the bottom of the vertical piece of wood that holds the dial gage. Here is the meter mounted on a blade.

https://lh3.googleusercontent.com/fLXbFS99Vx5-EhfOT4U9B0vKm13z8_JjrPI8VouMV9NmT3uwF5X8hqG0mcjr-b_mnMlXPPvjhBDQnD8Dx_RBKCRb6WVFQJVHfTWpbgDWdsxa-QUanraKeqKbYV_uYIzZM42341of2s-STghyfZmDqHLOyQw2TTKukZhzLRmGUrf8PpyDnCklQHT9GccTs cOxGgNG1vPPIfNtH0aX-WeP6iQhCuc-vwG-ckNHLwDmgODLYlYn2cKrrt3hVmXqmY7i0L1HRfuBA1HPiw_-wiQ_yEagXw-AEV0rLWLge6BA3_hx3lX3mEWF9_YgF1BXOEu54PbLeMXDZaCrd 0_1I1zj36Zd-Mb-921JNlHqE2ogLm36uOFVuDJsMT6NfD7kIMJ-v5324AkCBasU7lLSMy984XxYRrB2hljlOX0W0qFTRT3nD9DLcV BbsGbo7lZB_YbISQeSOZge5sl4vpR-Q5poT4KAY2NAtQ3sBNYJr0FVhYsJo-3dbcelGktMtZ5UdQTi4e-GSdLyMAZZ23A2HStXEWP480nt0RsiG_ffVnP7HIsrURi_7n2VY b7pFfhQHGAuVpSVOlcyKz-zpXv1TOx_7icEAWaGHI9blCMZ7mXRz87XuqQJINeERLRbo27W3 ISFt8I481_AYQSXUm0S9HKsNSA1b8en-1I9w3ED1YrAHg0tvRoRwHzO9mPtfFFnImZFRnMqieCCcNOHjY7 hxCfIOsLv5dDgq_qqD68OauoJG2Kn7g9hKw=w835-h626-no


The gage length (the length of the spine) on my meter is 12". The Young's Modulus of steel is approximately 30 x 10^6 psi. Therefore, for every 0.001" the dial gage moves the tension changes by 2500 psi. So if you want to put 25 ksi on a blade, like my Woodmaster CT, you need to increase tension until the dial gage changes by 0.010". For a meter with a different gage length use the following formula:

Dial gage change (0.001") / gage length (inch) x 30 x 10^6 psi = Tension in psi.

To use the meter, install the blade, put a moderate amount of tension on it and get it to run on the wheels where you want it, then lower the tension to zero. To do this put the tension meter on the blade, making sure there is a gap of about 0.020" between the bottom clamp block and the spine. Now reduce the tension on the blade and watch the dial gage. When it stops moving you are at zero tension. Repeat it a couple of times to confirm. Now either reset the dial gage to zero or just note the reading. Now increase blade tension to apply whatever amount of tension you want.

JOhn

Using this gage I found that the difference between applying 25 ksi to a Woodmaster CT and 42 ksi is surprising little. At 25 ksi the arrow on the saw's tension indicator was just below the 1" blade mark while at 42 ksi it was just above it, less than 1/2 a turn on the tension wheel.

[Frederick Skelly]

Thanks John! Appreciate it!
Fred

[ChrisA Edwards]

This looks simple to make

https://www.youtube.com/watch?v=9iAkRLvLAvI

[John TenEyck]

That's the same one I built, only mine is larger. Note that he never addresses how to establish zero tension, and that's key in getting accurate results.

Also, his comment about manufacturers recommending 15 ksi must pertain to a limited subset of blade manufacturers or maybe those who make bandsaws that can't apply much tension (like my old CI Delta 14", on which 12 ksi is all it's comfortable with on a 1/2" blade). Anyway, Lennox states that their blades are designed to handle up to 30 ksi, and I typically run about 25 ksi on blades on my larger BS.

John