Bandsaw.......I got a problem here...

[Jebediah Eckert]

I have a Laguna LT16HD bandsaw (ACM) that was made in 2001 with a 3hp Italian Motor.

I bought it with light use from the original owner maybe 7 years ago. This weekend I had issues I just can’t figure out. I’m pretty confident I can properly setup the bandsaw for tension, blade tracking, guides, fence etc etc. but either way I did it the same as I always have done.

I was ripping a bunch of 8/4 soft maple that I just finished milling flat and square. After a couple cuts the blade started to track like a snake swimming through the water. I stopped the machine and readjusted everything. I started cutting again and after a few cuts it started doing it again. With a bunch of work ahead of me I decided to change to a brand new blade, even though I was pretty sure this one was sharp. Put the exact same blade on, but new, and went back at it.

First few cuts were great then it started again towards the end of the cut. Out of ideas I just cut the next board and it was fine. A few would be nice and straight then it would start up again. It would only happen towards the end of the rip. Some boards were 18” and others were 27”. I adjusted feed rates, pressures, everything. Never had this happen before and I was out of ideas as to what to even try.

So I kept going and had the saw running for almost and hour cutting. If it started serpentining again I just pushed through as it wouldn’t matter much for final project. Added info is that once it started to serpentine it just would get progressively worse until out of the cut.

Well after about an hour of cutting I shut it off to rejoint a few boards. When I went to start it again it was very slow then died. I looked behind the saw the capacitor failed bad. It is the original 20 year old capacitor.

I have a friend coming over to give me a hand with the capacitor, he knows motors.

So any ideas as to what was going on?

457335

457336

457337

457338

[Andrew Hughes]

That’s pretty much what I experienced when my capacitor went bad. My guess is the motor looses power and the cut suffers. Kinda like a belt slipping on a pulley.
Thats a nice saw the 16 hd.

Heres what my capacitor looked like and what I replaced it with. Runs like a scalded dog now.

[Jebediah Eckert]

Interesting. Thanks for the response. So you got the wavy cut also?

I’m going to call Laguna tomorrow and see if they know what to replace it with. There aren’t any markings on this one.

[Andrew Hughes]

Mine went out slowly then one day poof. But I do remember feeling frustrated with my blades didn’t seem to last as long. My saw takes a 178 inch blade.
When I put capacitor in I ran a regular 3t hook blade until it broke. It just kept going.
I think you’re going to be a happy bandsawer when you get the new cap. :)

[Jebediah Eckert]

Thanks Andrew. Appreciate it. Now I just have to figure out what capacitor I need........

[John K Jordan]

That’s pretty much what I experienced when my capacitor went bad. My guess is the motor looses power and the cut suffers. Kinda like a belt slipping on a pulley.
Thats a nice saw the 16 hd.


I know nothing about that saw but my capacitor experience on my 18" Rikon was a bit different. When the capacitor failed suddenly the motor would just hum and fail to run. I removed the bad capacitor. While waiting for the replacement from Rikon I used the saw a LOT with no change in the power or function. I had to "jump start" the saw every time I turned it on by turning the motor manually. (This might sound dangerous but I simply pushed down on the blade with a piece of wood immediately after flipping the switch on.) Might remove the cap and try that and see if it makes any difference.

We had the same experience with failed capacitors on two lathes, a Jet mini and a Delta midi. In both cases the lathes continued to work normally with full power once given a twist on the handwheel. (Could even make the lathes run backwards.) I did remove the failed capacitors right away on both lathes if that makes any difference.

BTW, the failed cap on my Rikon looked almost exactly like the one Jebediah's picture. That's about the limit of my experience with motor capacitors except I understand there are start capacitors, run capacitors, and start/run capacitors - the motor expert friend should be a good resource. Once you figure the requirements you can usually buy a suitable capacitor locally. It doesn't have to match exactly as long as it is rated higher than the orig but sometimes finding one to fit into an existing protective can or "wart" is a problem.

[Sam Puhalovich]

I have a made-in-Italy 2005 LT 16 HD with a made-in-Italy Seimec 2.2 KW motor. About 8 years ago it suddenly refused to start and I was able to find that the capacitor needed replacement. I replaced-it with a Proline PB400E000P440EA 40uf 440VAC ... I bought it a motor service place for about $23 ... which was about 1/4 of what Laguna wanted for a replacement. I could not find any capacitor info on the wiring diagrams or parts listing.

[Jebediah Eckert]

Thanks for the info.

Here is the plate on the motor. I do see a 2.2 kW on the bottom left so maybe it will be the same as Sam? I don’t think size will matter for this one. It was just zip tied to the side of the motor.

[John TenEyck]

I think you've got two different problems. If the motor doesn't run at full power the blade won't cut as fast but it should still cut straight unless you are over feeding it. Obviously, replace the capacitor and then you'll know.

John

[Jebediah Eckert]

That makes more sense to me John, but I’m hoping the capacitor caused the wavy cuts, not the other way around.

[Randy Reitz]

Could it be from the blade heating up and expanding thereby reducing tension? 8/4 maple can be a tough slog for a bandsaw blade.

[Jebediah Eckert]

That sounds possible. But I have done a few runs of 100 board foot in the past month or two and haven’t had that issue until now.

Cutting one after another it may cut straight 3 times. Then on the 4th will serpentine after the halfway point, and then progressively worse. Then it might be fine on the very next cut.

[Rod Sheridan]

That sounds possible. But I have done a few runs of 100 board foot in the past month or two and haven’t had that issue until now.

Cutting one after another it may cut straight 3 times. Then on the 4th will serpentine after the halfway point, and then progressively worse. Then it might be fine on the very next cut.

Loose or worn tires?

Regards, Rod.

[Erik Loza]

I think you've got two different problems. If the motor doesn't run at full power the blade won't cut as fast but it should still cut straight unless you are over feeding it. Obviously, replace the capacitor and then you'll know.

John


I'm with John: This almost seems like two different issues. Not seeing how reduced power will cause a wandering cut. My gut response to that is lack of adequate blade tension. Curious to hear how it goes.

Erik

[Edwin Santos]

When the serpentine waving starts happening, have you paid attention to the thrust bearing to see what it is doing?
I have a suspicion it will be spinning furiously and if so, it indicates inadequate tension, too much feed rate, or the thrust bearing being too close to the back of the blade.
Incidentally all three of these variables are co-dependent.
Dull blade is another possible related culprit.

[Jebediah Eckert]

The capacitor won’t be here until Thursday. I should have an update by the weekend. Anyone of the above is certainly a possibility.

I think I can rule out dull blade. The blade it started on was nearly new, I changed to second brand new blade in case the first one had a defect. I have ceramic guides but I didn’t notice any extra sparks or anything like that. The tires are both in good shape best I can see.

Feed rate was consistent and slow. Maybe noteworthy, once it started to serpentine I tried slowing to a crawl and it still got worse. Then the very next cut it was fine........

[John TenEyck]

Low tension. With enough tension the guides do little, including the rear thrust bearing.
Wrong blade for the job.
Maybe both.

John

[Doug Garson]

I'll throw this out for the experts to comment on. You say you cut several pieces with no problem then it goes serpentine but the next piece cuts ok. Could it just be some really wonky wood?

[Jebediah Eckert]

Good thought Doug, but no. It was all pretty straight grained 8/4 soft maple.

Tension makes sense but I’m not sure how I screwed it up after 3 blade changes. I’ve had the saw for many many years and do it the same way I always do......but certainly a possibility.

The blade is a 1/2” 2-3 tpi Timberwolf Vari-PC. They actually recommended it for the 8/4 soft maple. Of course that could be wrong also. But I have used that blade before on the same saw, on tougher wood, and no issue.

[Edwin Santos]

The capacitor won’t be here until Thursday. I should have an update by the weekend. Anyone of the above is certainly a possibility.

I think I can rule out dull blade. The blade it started on was nearly new, I changed to second brand new blade in case the first one had a defect. I have ceramic guides but I didn’t notice any extra sparks or anything like that. The tires are both in good shape best I can see.

Feed rate was consistent and slow. Maybe noteworthy, once it started to serpentine I tried slowing to a crawl and it still got worse. Then the very next cut it was fine........

What type of blade were you using? Specifically the pitch.
This has happened to me before. Once it was tension and the clue was that the blade was pushing too hard against the thrust bearing. Another time it was because my belt had become worn and cracked in a few places, and it was slipping thus robbing some of the power of the saw.
I'm a bigger believer in cause/effect than coincidences and with your capacitor failing, I would do nothing and see if upon installation of the new capacitor the problem disappears. If not, pretty much all the suggestions you have received are legitimate possibilities.

[Jebediah Eckert]

The blade is a 1/2” 2-3 tpi Timberwolf Vari-PC.

[John TenEyck]

Good thought Doug, but no. It was all pretty straight grained 8/4 soft maple.

Tension makes sense but I’m not sure how I screwed it up after 3 blade changes. I’ve had the saw for many many years and do it the same way I always do......but certainly a possibility.

The blade is a 1/2” 2-3 tpi Timberwolf Vari-PC. They actually recommended it for the 8/4 soft maple. Of course that could be wrong also. But I have used that blade before on the same saw, on tougher wood, and no issue.


What's the tension? Using the saw's indicator is pretty much useless unless you calibrated it against a tension meter.

John

[Jebediah Eckert]

I just check the deflection with my finger against the upright side of the saw. A bit back I used the “flutter” test a try and ended up nearly identical as to where I was with my finger.

I have never had a tension meter before. Come to think of it I’m not even sure what one looks like.

When I get it running I will certainly try upping the tension. Would low tension make sense that it cuts fine a few cuts then goes haywire, then back fine again? Either way I will give that a try.

Thanks

[Larry Frank]

It is pretty easy to measure tension using a digital caliper. There were instructions somewhere in posts.

I did it a couple of times and figured out that t h e gauge on my Jet was close.

[John TenEyck]

Lots of people do it that way, Jebediah, but when you run into problems you have no clue if the tension is high enough. Blindly adjusting tension is like driving without a speedometer. Fortunately, cars come with speedometers and for the cost of a dial gage and an hour of your time you can have a tension meter to check the tension on your bandsaw blade. Once you know the tension at a particular setting for the on board pointer you can use that in the future to tension the same brand/size blade.

https://sites.google.com/view/jteneyck-woodworker/current-projects/bandsaw-blade-tension-meter?authuser=1

Increasing tension is not the right move unless it's low. Despite what Timberwolf advertises blades don't cut consistently well at low tension. 20 - 25 ksi is a good range for most blades if your saw can muster it. If it can't, and my little 14" Delta can't, then your set up has to be just about perfect to get consistently good results. If I have a new 1/2" blade on it with 12 ksi tension and have it tuned so that it cuts straight and parallel with the miter slot, it will cut fine as long as I am patient. Cranky grain, however, can still cause problems sometimes. On the other end of the spectrum, my 17" Grizzly easily tensions a 1" blade to 25 ksi. Once it's set up it will cut through nearly anything about as fast as I can push the wood into it, without wandering. Tension is your friend.

John

[Jebediah Eckert]

Thanks John. I can’t find the one using digital calipers, but yours looks doable. I’m going to read that and make one while I’m waiting for the capacitor.

How do I even know what the tension should be for that blade, manufacturer? Twenty years of bandsawing I never gave it this much thought, but I guess I need to eliminate that.

Thank you.

[Andrew Hughes]

I’ve never used a tension mechanism on a bandsaw blade. I just set it on the scale and go a bit over and always have my blades cut at 178 inches.
Im not convinced it’s really wise for every saw and blade. Bandsaws have so many different blades and woods that can determine the quality of a surface.
I think it better to focus on tooth count and wood thickness. Then the property of the wood and that’s a whole kettle of fish.

[John K Jordan]

Thanks John. I can’t find the one using digital calipers, but yours looks doable. I’m going to read that and make one while I’m waiting for the capacitor.

How do I even know what the tension should be for that blade, manufacturer? Twenty years of bandsawing I never gave it this much thought, but I guess I need to eliminate that.

Thank you.

Jebediah,

These are some links I saved where John T wrote about bandsaw tension. I didn't go through each one just now but perhaps some are different from what you have seen. One shows the digital caliper method.

https://sawmillcreek.org/showthread.php?290973-Bandsaw-tension-new-math&p=3113838#post3113838

https://sites.google.com/site/jteneyckwoodworker/current-projects/bandsaw-blade-tension-meter

https://sawmillcreek.org/showthread.php?277420-Do-you-use-a-bandsaw-blade-tension-gauge&p=2958508#post2958508

http://www.sawmillcreek.org/showthread.php?250388-Bandsaw-blade-tension&p=2640833#post2640833

JKJ

[Jebediah Eckert]

Thanks John. I’ll check them out.

[Jebediah Eckert]

The capacitor came last night and I put it in today. I could not figure out what side was “common” so I guessed at it. I know very little about these things but it seems to have polarity according to the bandsaw’s wiring diagram. I figured I had a 50% chance of getting it right. Put it on, buttoned everything up, and it ran fine.

The blade was left “as is” when it failed. It seemed to be cutting fine but it’s not a good test yet. I only ran it for a couple minutes. The capacitor didn’t heat up and everything seemed fine. But from my previous post it doesn’t always cut wavy so it still may happen.

I’ll cut a bunch this weekend and will report back.

[Jebediah Eckert]

MAYBE I FIGURED IT OUT?

I ran it today for close to an hour and it ran fine. So I think the capacitor just let go at the 20 year mark.

Now the wavy cuts.....I finished that 8/4 job on the tablesaw, so I didn’t have anymore of that to do. Today I was also cutting a bunch of soft maple, but it was only 3/4”. The first couple went through fine, then the waves started! I reset my guides and checked my tension. The tension felt right to me, and is where I always set it. I intended to make a tension tester, but my head just started to hurt reading about the math.

To cut to the chase....my fence somehow got out of parallel with the blade. I have a fence that is adjustable for drift. Prior to all these issues I used the fence in the short position, then put it back to the tall for the soft maple. The levers that release the fence are below the levers that adjust for drift. In my head I always get them confused and they make more sense the other way around. I remember loosening the drift levers to change the fence position. In the process I moved it off I guess?

When I was cutting the soft maple I was using a feather board. All the boards were rough width, but not exact. I’m thinking that the wider ones were pressed real right against the fence and those gave me the wavy cut? Maybe the “drift” was pulling it away from the fence and the feather board was pushing it back. Maybe that explains why they all started straight and got progressively more wavy on the boards that were tight?

That’s all I can think of anyhow, maybe that doesn’t even make sense. But I got the fence back parallel with the blade and I cut dozens of 3/4” stock fine without any Wavy incidents.

Only time will tell but it seems to be solved for now......

[Andrew Hughes]

I was going to mention something I remembered today with drift.
When I changed my capacitor I had to remove the table. I didn’t get it positioned correctly and my blade wanted to cut away from the fence. Sometimes it’s the table sometimes the fence ?
Thanks for reporting back now we close the case on this one. :)