Tension gauge for bandsaw

[dave]

I am considering picking up a tension gauge for my new bandsaw. I would first like to hear opinions on how critical this is. I've read in several places that blade tension is very important for better cuts and longer blade life.

Thoughts?

 

[sapwood]

Dave,
A year or so ago, one of the mags did a review on bandsaw tension gauges . . . but I can't remember which mag :BangHead:

However, the general thrust was that few were better than the standard built in scales. I know some folks tune the tension by listening to the tone created by plucking the blade. Doesn't work for me though, as I'm somewhat tone deaf :eusa_booh

I'm sure someone else will tune in with the real answer

Roger

 

[CarvedTones]

I saw an interesting comment in something I read. It said that deflection was what mattered most, not tension. They are obviously inter-related, but the point was you are better off measuring how much force it takes to push the blade off to the side a given amount with the guides up than how much force is on the spring. The correlation between the two is not the same for different saws or even different blades on the same saw.

 

[Len]

I have to agree with Andy. When I was a machinist apprentice (several life times ago) we were taught the key to setting up the bandsaw was blade deflection - not tension. There was a home made chart taped to the upper blade cover showing how much deflection was okay for different thicknesses of material, and different types of materials and blades.

Len

 

[GarageWoodworks]

Dave,

I looked into buying one a while back and found that they were too expensive for my taste. You can make a DIY version that looks easy to build (I have yet to make one).

Check out pictures of one here.
DIY version in FWW if you have access here.

The amount of movement on the dial indicator is correlated with blade tension (see article or try a DAGS).

Good luck,
Brian

 

[dave]

Thanks everyone!

I think I've decided against getting one based on your statements and also due the fact I happened to pop into Woodcraft today and while waiting on one of the salesman, browsed through a book on band saws. The author's opinion was that the tension gauges did not offer much, if any, more accuracy over the built in "gauges" that some saws come with - especially for the price.

I think I also read something about deflection on another forum once, but at the time, didn't pay much attention.

Dave

 

[sawman101]

I am somewhat partial to the Timberwolf blades, available at Klingspors, and other places. I used to sell them in my sharpening shop up north. Anyhow, no 2 blades are the same. Every blade will have its own perfect tension level. With the Timberwolf, the setup takes a few minutes and several steps, and is basically based on blade wobble or deflection while running. I bought a quick release so I could release tension after using the saw. My band saw used to have noticable vibration, which came from the tires having flat spots from sitting still for long periods with tension on the blade. It has smoothed out quite a lot.

 

[dave]

The reason I stopped into WC was to pick up a couple Timberwolf blades. They were all out of the size I needed though.

 

[Alan in Little Washington]

You guys know I am a digital kind of guy who likes things with readouts, etc. so I have given this issue a lot of thought. I read the extensive and sometimes contentious thread on another forum discussing a magazine article by Mark Duginske (nationally recognized woodworker and author of an outstanding bandsaw book). Duginkse eventually weighed -in. He teamed up with a professional engineer to do testing of after-market bandsaw tension gauges. They determined most, if not all, were not accurate, reliable, nor repeatable, certainly not enough to justify their cost. Even DIY gauges using calipers, strain gauges, etc. were not reliable. If I remember they tested the Carter (mechanical), Lenox, and Iturra gauges. Their bottom line- the bandsaw manufacturers' marks are as good as anything. I tend to agree, but asked about the Carter electronic load-cell based digital systems ($150/$200) where the load cell is placed under the foot of the tensioning rod. I didn't get a satisfactory answer.

But, after thinking more about it, I had an epiphany. What is bandsaw tension, how is it determined and why is it needed? My take is it is not needed for anything but gross initial setting and short-term repeatability then it is up to the woodworker to tweak it. Think about it- where does a manufacturer's recommended tension setting, if there is one, come from? Trial and error through testing by a bunch of woodworkers testing that blade on bandsaws. They are combining an objective tension readout of some sort with a purely subjective determination of where a blade works best. There is no other way to do it!

So, if the only way to determine the best (tension) setting is by human trial and error, the results can vary. On top of that, any setting may change depending on blade age, temper and sharpness, as well as the thickness and hardness of the material being cut. I firmly believe there is no magic bullet. My recommendation is to experiment and learn your bandsaw. Learn what works and doesn't work for a particular blade. Once you find the tension where a particular blade cuts well make a mark on the saw. For a new blade you can't go wrong starting out with the manufacturers' marks. If your saw doesn't have marks try the vibration method.

Like anyone, I would love to be able install a blade and dial in a precise tension published for the blade, have the blade will work perfectly, and make me a better woodworker. Ain't gonna happen.

 

[Mt. Gomer]

Has anyone tried the Timberwolf instructions on other brands of blades? Does it work? I've pretty much given up on the tention gauge on my Rikon... doesn't even seem close.

 

[dave]

Thanks Alan, that makes alot of sense. The book you're refering to is the one I picked up while at the Woodcraft store. Very glad I did being new to band saws.

I tend to be a gadget junkie, but in this case I think I am better off without them. :wsmile:

Dave

 

[willarda]

I believe the tension gauges on the market measure the tension as the force to deflect the blade sideways. They do not measure the tension on the spring. The gauges attach above and below on the blade and the tension is measured in between.

The bandsaw guru down in Florida--has the great catalog on Delat and Jet 14" bandsaw conversion and and improvements--can not remember his name, sells an excellent gauge for good money and also has an article in his catalog on the utillity of gauges. The catalog by itself is worth getting (free). I made a number of significant improvements to my 14" Jet using this catalog.

 

[Alan in Little Washington]

I believe the tension gauges on the market measure the tension as the force to deflect the blade sideways. They do not measure the tension on the spring. The gauges attach above and below on the blade and the tension is measured in between.

The bandsaw guru down in Florida--has the great catalog on Delat and Jet 14" bandsaw conversion and and improvements--can not remember his name, sells an excellent gauge for good money and also has an article in his catalog on the utillity of gauges. The catalog by itself is worth getting (free). I made a number of significant improvements to my 14" Jet using this catalog.

While there may be one or two that do that, the majority of them measure elongation of the blade over a given distance. Elongation combined with the blade's modulus of elasticity, can be converted into the tension being applied by the spring.

The guy you are talking about in Florida, is Louis Iturra which I mentioned above. He sells aftermarket accessories for bandsaws. He has an extremely informative catalog which is well worth getting your hands on, but no website (still!) . I'm not sure it is current, but here is his phone # [SIZE=-1]1-888-722-7078[/SIZE]. Here is an old article that talks about him, his business, and catalog.