Band saw tension

[J. Dillon]

Attended the demonstration at Mystic CT on how to cut changing bevels with the band saw. It was very interesting.

A while back their was some discussion here by respected shipwrights that the tension should be slackened when not in use.

Remembering that I asked the shipwright about releasing the tension on the blade .

" He said we never do "

Is it just a matter for yard policy ?

What is the straight skinny ?

[Paul Girouard]

My .02 cents a shop would be using the saw a regular basis , a part timer might go months with out turning a saw on. Two different things , if you use your saw weekly / or outside monthly I'd leave it set. The long time between use would be where that spring tension would be harmful / not good . The shop's I've work at we never messed with the tension unless we changed blades . YMMV ,as will the reply's to this question :rolleyes: :D

[George Roberts]

Spring tension or lack there of is a foolish issue. When under tension there should be no "creep" in either the spring or the blade that would reduce the tension.

[Dave Fleming]

It wasn't so much for the tension factor itself. It was done to prevent developing FLAT spots on the tires.

Remember those were the days before Poly or Urethane tires.

It was a big job to dismantle a pair of bandsoar wheels, send them to the vulcanizing shop, be without the big soar for more than a week, get them back mount and reset the tension.

When you are working a 26 or 36 inch tilting frame bandsoar you sure as hell can tell if there is a flat spot on a tire. Whole machine vibrates, blade won't track worth a damn with a good chance of breaking a blade too.

The vulcanizer shop not only mounted and ground new tires but, then had to balance each one.

[pipefitter]

On regular bandsaw wheels with replaceable tires,leaving the tension up will also enlarge the tires to where the will slip and even come off.Leave it tensioned for a year or more in warm climates and you may even see daylight between the tire and wheel where the blade is not touching.

[George Roberts]

I am sure that there are/were bandsaws that used poor materials, in the springs, blades, or tires. After all a lot of "good" workmen seem to have problems with simple power tools. (end of rant)

If you find it helpful to loosen the blade, do so.

[michigangeorge]

My old Sears bandsaw would jump all over the place because of a flat spot on the tire and likely bearing wear because I never released the tension. My new Delta X-5 has a nice big tension release lever which is much better :-) It also makes blade changing much faster which means I might actually use the right blade for the job!

[Ron Paro]

I have a little 9" Delta Benchtop bandsaw. The manual does advise releasing the tension when not in use. I have found that if I am using it a few times a week, I can leave it tensioned without any problems. If I know that I will likely not be using for more than a week or so, I release the tension. I have used this saw for about six years, and have had no problems at all with the wheels or tires. I think it helps that I clean it out after I use it, most of the time.

[Lew Barrett]

I have a 50+ year old Boyce Crane 14" bandsaw. I'm wondering if I can trust the tension indicator. If the spring is weakened with age might the indication be off and if that's the case, how can I tell how to set the proper tension?

Reef it down until the blade breaks at the weld, then back it off a turn:D

Actually, it's not that critical. Built in tension scales are only approximations to begin with.

[Kim Whitmyre]

Here's a downloadable pdf file that will show you how to make a simple, accurate gauge for bandsaw blade tension:

tension gauge at Fine Woodworking (http://www.taunton.com/finewoodworking/Workshop/WorkshopPDF.aspx?id=2702)

I made one a few years ago: it's handy because after setting the tension properly, I count the turns as I loosen the blade. Apply this number of turns next time and I'm in the ballpark.

[Eric D]

Is it just a matter for yard policy ?

What is the straight skinny ?

In every manual for every bandsaw made today, they all recommend releasing tension when not in use. Even with new tires, they will develop flat spots. One issue that is not mentioned by anyone yet is the fatigue on the bandsaw blade itself. The body (part behind the teeth) will fatigue easier/quicker which will shorten the life of the blade. In addition, you will over time have more of a wander or barrel cut with a blade that has been tensioned for a long period of time.

In wood working shops that always use them day in, day out, I can not comment.

Mark Dunginiske (sp? I am close) has a book on bandsaws which is considered the bible by many which will delve into this topic quite thoroughly if you want further reading that is less anacdotal than this.

One last point, several saws made today have a quick release tension bar that you simply push up to loosen, pulling down to tension. You can even buy aftermarket ones for older saws so you don't have to sit there turning a knob forever. Some may cry marketing, but dang, they are all doing it so maybe it has some merit worth looking at.

Snap one blade while sawing, you generally try to find ways to avoid it....