Damaged Band Saws from Overtensioning

[Ken Fitzgerald]

Gary,

As you are probably aware, last year the members here primarily turners sent me a lathe, tools, videos etc. I also on the advice of turners here bought several books. I learned to turn on my own. The nearest turning club is 110 miles north of here. I'm very mechanically and electronically inclined. I install and repair CT scanners, MR scanners and x-ray equipment for a living. I've overhauled car engines, ground and lapped the valves....I started working on oil rigs full time when I was 15. I worked morning tower 11-7 for my Dad and went to HS days. In the Navy I worked Air Traffic Control maintenance and repaired equipment used aboard Fast Attack Subs..... I learned to turn on my own and I was more than just a little nervous the first time I put the gouge on the tool rest and then "heel and toed" it into the spinning chunk of wood.

Not everybody has my experience or natural talents. If I had my druthers, I learn to turn from an experienced turner. I'd learn to use my b/s from someone with a lot of experience.

Reallistically, most springs,and other mechanical things are designed to work about mid-way through their range of their mechanical range. So telling someone if they don't have a tension gauge on the b/s to compress the spring about 1/2 way through it's range.....sounds pretty sage to me.

Giving somebody like myself, totally ignorant about bandsaws, a starting point isn't a bad thing.

BTW a friend is sending me Mark's video and first book.

BTW..I'll be ordering my first b/s in about 4 weeks. Though I have a specific b/s in mind, I'm still looking at options.

[Mark Duginske]

I

Why is the flutter method not better than compressing various sized/strength springs halfway?

Alex

I have experimented with the flutter method and noticed that there are many variables. It works fine for some people and that is "great". I recently helped a friend tune up a Jet saw that he go at an auction. Just for the fun of it I tried various test including using a Carter ETG electronic gauge.

The saw needed help. Initially it would "flutter" with very low tension on the saw. The bottom wheel and top wheel were out of alignment by 1/4".
When the "riser" was added it the wheel misalignment was even worse. With each improvement the tension at which the blade would flutter would change. My unscientific observation is that saws with a riser block flutter at a different tension than those without. Could it be the longer span of the blade? Perhaps, some one could add some engineering or physics to this conversation.

"Flutter" is an easy technique which is good. However, my experience is that it is on the low end of tension required to use the saw for heavy use such as resawing. Initially to blades from the source who recommend that method are quite sharp. But, as the sharp blades dull, more tension may be required and thus the "flutter" method may require more than the initial rotation of the tension knob after the saw blade stops fluttering.

[Gary Keedwell]

Gary,

As you are probably aware, last year the members here primarily turners sent me a lathe, tools, videos etc. I also on the advice of turners here bought several books. I learned to turn on my own. The nearest turning club is 110 miles north of here. I'm very mechanically and electronically inclined. I install and repair CT scanners, MR scanners and x-ray equipment for a living. I've overhauled car engines, ground and lapped the valves....I started working on oil rigs full time when I was 15. I worked morning tower 11-7 for my Dad and went to HS days. In the Navy I worked Air Traffic Control maintenance and repaired equipment used aboard Fast Attack Subs..... I learned to turn on my own and I was more than just a little nervous the first time I put the gouge on the tool rest and then "heel and toed" it into the spinning chunk of wood.

Not everybody has my experience or natural talents. If I had my druthers, I learn to turn from an experienced turner. I'd learn to use my b/s from someone with a lot of experience.

Reallistically, most springs,and other mechanical things are designed to work about mid-way through their range of their mechanical range. So telling someone if they don't have a tension gauge on the b/s to compress the spring about 1/2 way through it's range.....sounds pretty sage to me.

Giving somebody like myself, totally ignorant about bandsaws, a starting point isn't a bad thing.

BTW a friend is sending me Mark's video and first book.

BTW..I'll be ordering my first b/s in about 4 weeks. Though I have a specific b/s in mind, I'm still looking at options.

Ken...Don't know where your going with this....what I'm trying to say is that almost 90 posts on how to tighten a blade seems out of proportion as compared to the many skills needed to be a skilled woodworker. But apparently there are alot of people having a hard time ...so there must be something to all these posts. Sorry about all my unfocused english this morning...coffee hasn't kicked in yet. I don't mean to demean anybody because I've had days where resawing doesn't go like I want it to. But I found out that most of my solutions were that I was using the wrong blade for the job at hand.
Gary K.

[Mark Duginske]

Ken...Don't know where your going with this....what I'm trying to say is that almost 90 posts on how to tighten a blade seems out of proportion as compared to the many skills needed to be a skilled woodworker. But apparently there are alot of people having a hard time ...so there must be something to all these posts.
Gary K.

Gary,

Looking back this thread was not about "tightening the blade", it was about trying to get a feeling for how many people had accidently damaged their band saws by overtensioning. I thought that there may be a couple of post showing pictures of bent top wheel hinges and broke top or bottom shafts (which we still have not gotten). Since the thread was titled "...overtensioning..." the discussion move to overtensioning and then tensioning in general.

I to am surprised at the number of post but I think that it shows the interest in (or confusion about) the band saw. Unlike the other circular saws the band saw needs to be "tuned" like a musical instrument
and that is a skill not easily communicated.

[Al Willits]

Been enjoying the topic, not so sure I'd say its gotten to be a little much though, some like to know the who, what, where, when and why of a product, and I think that could get pretty involved.

Then there's people like me, who at this state of the learning curve are perfectly happy with starting at the half way point of the spring and making cuts to see what happens and adjusting from there.

Personally with the Wolf blades I find I can set the tensioner at just shy of what it says to and it cuts just fine.
Also think no matter what ya use to set a tool up, the proof is in the using.
Unless of course your an engineer.....

Al

[Ken Fitzgerald]

Ken...Don't know where your going with this....what I'm trying to say is that almost 90 posts on how to tighten a blade seems out of proportion as compared to the many skills needed to be a skilled woodworker. But apparently there are alot of people having a hard time ...so there must be something to all these posts. Sorry about all my unfocused english this morning...coffee hasn't kicked in yet. I don't mean to demean anybody because I've had days where resawing doesn't go like I want it to. But I found out that most of my solutions were that I was using the wrong blade for the job at hand.
Gary K.

Gary,

I've been looking at b/s a lot the past couple of weeks. I'm pulling the trigger on a b/s in the last week of September. I've looked at inexpensive and what I consider expensive. Some have tension indicators, some don't. All I was trying to say that I didn't think Mark's giving a general starting point for tensioning was a bad thing. That's all I meant to say.

1st cup of coffee too!

[Mark Duginske]

Been enjoying the topic, ..............

Also think no matter what ya use to set a tool up, the proof is in the using.
Unless of course your an engineer.....

Al

I think that Al Willits makes a very good point. The proof is in the using and this thread has given the SMC group a chance to share their experience and concerns. The statement..."the proof is in the using"...
shows a lot of midwestern common sense.

Until one "learns" the nuances of tuning the band saw it is a temptation to
use "engineering" solutions such as the clamp on gauges etc. After reading Mike Cutler's comments in this thread the point is that these are not applicable to the woodworking band saw.

The saw gauge, the "flutter test" and compressing the spring half way are places to start. The band saw user has to realize that the saw requires experimentation and performance may change as the blade dulls or heats up and that one has to keep an eye on the saw and possible "dial in" a change. A little experimentation with the saw is a good thing.

[Alan Schaffter]

Mark thanks!

Maybe repeating parts of a previous summary, but for me it sounds like first, follow the saw's tension markings (or half spring compression if there are no markings) which will get you in the ball park, then adjust the tension as necessary. Take note of what setting you are using and build up some experience as you go. Different wood, thicknesses of wood, and blades will act differently. But, by all means, don't bottom out the spring.

This brings up another question (already addressed?) that gets back to Mark's original issue- seems improbable, but has anyone damaged the tension mechanism (hinge, pins, etc. etc.) of their bandsaw by tensioning it without bottoming out the spring?

[Chuck Lenz]

Mark thanks!

Maybe repeating parts of a previous summary, but for me it sounds like first, follow the saw's tension markings (or half spring compression if there are no markings) which will get you in the ball park, then adjust the tension as necessary. Take note of what setting you are using and build up some experience as you go. Different wood, thicknesses of wood, and blades will act differently. But, by all means, don't bottom out the spring.

This brings up another question (already addressed?) that gets back to Mark's original issue- seems improbable, but has anyone damaged the tension mechanism (hinge, pins, etc. etc.) of their bandsaw by tensioning it without bottoming out the spring?

Ummm Alan, I believe my hinge shaft was damaged because it's a under engineered part, not because I tightened it too tight. The new hinge shaft I got from JET was beefed up considerably where the old one had failed. I'm sorry but this whole thread of blameing everyone for over tightening bandsaw blades has gotten wayyyyyyyyyyy too deep. Who's got the time to play mad scientist with clamps and calipers everytime they use their bandsaw ? You wouldn't get any woodworking done ! It's not the operator, it's the saw part thats to blame. You don't see anyone breaking or bending hinge shafts on bandsaws larger than 14" do you ? Someone in here mentioned that they had broke their hinge shaft on a certain brand and they got one for a different brand saw and it looked just like the one he had, and it fit his saw. The 14" saws are all geting to be that they have the same castings but are branded different. Someone has also mention in here that you shouldn't use a blade wider than a 1/2" in these saws, hogwash ! JET says I can use a 3/4" blade and I expect them to stand behind that claim.