Bandsaw Tension

[Joseph Fenske]

I read this article and I thought it was interesting...

http://hackaday.com/2017/01/28/bandsaw-tension-gauge-uses-raspberry-pi-and-load-cell/

[David Pascoe]

I saw tropical hardwood 6" x 3/32" veneers on my Delta 14 every day and have found no need to make a big deal over blade tension. I use the tension that works best and years ago marked that on the spring gauge and have not changed one iota since. Far and away the most important factors are SHARP, high quality blades. DULL BLADES WILL NOT CUT STRAIGHT. And steel blades dull quickly.

[Van Huskey]

I constantly preach about the benefits of proper bandsaw tension but most people have made up their minds and that is where they stay. My analogy (though far fro perfect) is a car tire, sure an underinflated or overinflated car tire will get you from your house to the grocery store but it doesn't mean it has the best possible traction/handling/comfort/wear. A load cell based system is the best solution (and has been on my to-do list for a while) because not only is it simple and repeatable it can monitor the system in real time and allows you to simply and easily account for heat induced stretch if you like. Admittedly the stretch from thermal expansion will be small so not much of an issue.

I have a couple of the old Carter load cell based tension gauges that I have used on 14" cast saws when I have had them and they work well. Sooner or later I will build one for some of my larger saws. Thanks for posting.

[lowell holmes]

I saw an earlier Snodgrass video and I adjust tension using his flutter method. I've never had any issues at all. I've been doing this for about 10 years.
Like a previous post, I see no reason to change.

[Bill Rhodus]

I like your thoughtful approach Van; most people don' t take blade stretch or irregularities of bandsaw length into account when considering tension. Just because your saw worked well with a blade doesn't mean it will work the same with a replacement that is a little longer. I just posted a comment to Eric Loza's post about a resaw that referenced the tensioning of industrial blades with an air bag. This allows for small differences in band length, heat expansion, and provides consistent tension.

[David Kumm]

Always lots of discussion about tension. Really depends on machine and blades. Small machines can't tension without all kinds of tracking problems so best to stay with sharp low tension steel blades. Works most of the time. Large machines with carbide blades costing upwards of $300 operate best at high tension. If you do any quantity of 14+" resawing you know that carbide needs 25000+ lbs to handle a decent feed speed, particularly if using a feeder. No one answer covers territory. Dave

[David Pascoe]

So what difference does it make if you are getting perfect cuts? If one is sawing veneers, saw set up is more important and that is mostly a matter of getting the blade to track exactly in the center of both wheels. If not, you get toe-in or toe-out and veneer thickness will taper off length wise. If tension too loose, the blade will start scalloping or veneer thicker at top than bottom. Of course, all this is dependent on feed rate, type of wood, hardness, oiliness causing dust build up in kerf and so on. My point being that slicing perfect veneers is a lot more than just blade tension and there is more than one way to achieve our goals. However, some people insist that their way is the only way.

[Van Huskey]

So what difference does it make if you are getting perfect cuts?


The problem is nobody is getting perfect cuts, they don't exist. The real question is what is good enough, for me good enough is when I have maximized the quality of cut my tooling and machines will produce which with a bandsaw only happens when tension is correct or at least as close to correct as the saw will allow. In the latter case a different blade more in line with what the particular saw can tension will likely produce better results. Nobody suggests tension is the ONLY critical issue with setup it is just another part of correct bandsaw setup. The "weakness" of a bandsaw is you are using flexible tooling but want it to act like rigid tooling. The only way to approach this ideal is through proper tension, too much or too little will cause issues with the cut.