Bandsaw cuts sporadically

[John Coloccia]

Here's an interesting problem. My Grizzly G0514X2 (19") bandsaw started doing something funny. The blades cut in a "jumpy" way. It rhythmically goes back and forth between cutting very fast and cutting just a little slower. It happens with different blades. I'm also noticing a little bit of additional vibration. It gets worse when I use my 1" resaw blade but it's only really noticeable when I'm pushing and actually resawing.

OK, so obviously something has crept in to the works. My top tire is true to within .012, and the bottom is similar. Before I start troubleshooting from the beginning, does anyone have any suggestions to look at first?

[Dave MacArthur]

What are you sawing? Things like fir with significant annual rings will cut noticeably fast/slow as you go through the rings. That 's the only time I've noticed the behavior you describe, but it was noticeable. I see it a lot on 2x4s when cutting across rings.

[John Coloccia]

What are you sawing? Things like fir with significant annual rings will cut noticeably fast/slow as you go through the rings. That 's the only time I've noticed the behavior you describe, but it was noticeable. I see it a lot on 2x4s when cutting across rings.

Rock hard maple :) I know, it's strange. I know I have a little vibration but I'm having trouble explaining the funky cutting.

[Tri Hoang]

Inspect the blade for any sign of cracks. You might have one some where.

[Prashun Patel]

Did you check your belt and the tension? Perhaps it's skipping under load?

[glenn bradley]

If it is happening with different blades I would suspect the material or the ability of the blade to stay at a consistent speed. Try different materials as a test. If the behavior is consistent as the material changes, check your tires and blade path. My .02.

[Phil Thien]

Did you check your belt and the tension? Perhaps it's skipping under load?

That is my thought. If it is happening with multiple blades, I imagine the belt is slipping. This would also increase vibration.

[John Coloccia]

You guys may be on to something with the belt. It seems to be tensioned just fine BUT I decided to run it with the doors open and just watch it, and it's doing a funny oscillation. Maybe it's just stiffened up/stretched out, or whatever happens to belts. I'll replace it today with a link belt and see what happens. For the record, it can still pass the penny test, even in the condition it's in now, and the nickel test is never in question until I start doing some heavier resawing. With no blade, I AM starting to feel a little vibration that wasn't there a few months ago, so this is an excellent place to start.

I let you know how it goes. I wouldn't have thought to look at the belt other than checking the tension except so many of you chimed in to really check out that belt...so thanks :)

[george wilson]

Exactly what blades are you using? That odd cutting is usually a sign of a dull blade,but you say you are using different blades. Are they new,or used blades?

[John Coloccia]

Update:

I replaced the belt with a V-belt and that certainly helped the unloaded vibration. I still have an annoying vibration otherwise, though. I'm currently using Timberwolf blades. Maybe I just need to try another blade. Everything else appears to proper.

You know, it makes me wish that someone had a service where I could pay them $100 to come in and tune up my machines. This is SUCH a waste of time that I could be spending working.

[Greg Portland]

My Grizzly G0514X2 (19") bandsaw started doing something funny. The blades cut in a "jumpy" way.+1 on thinking it's a blade problem. How thick is the wood and what blade type are you using (size & tooth pitch please).

[Kyle Iwamoto]

You know, it makes me wish that someone had a service where I could pay them $100 to come in and tune up my machines. This is SUCH a waste of time that I could be spending working.

Do you have a band saw tune up book? There are a couple books reccomended by this forum. The bandsaw book and bandsaw basics I think. I have another generic tools book that had bandsaw set up techniques. Any book will tell you how to set your guides, tension your blade and a host of "little" things that will make your saw cut like it should. And it's less than 100 bucks!

You saw should not vibrate too badly, something may have gotten out of alignment. IMO blades should not cause the saw to vibrate. Changing out the blade probably won't stop the vibration.

[Van Huskey]

I think it is time for the full troubleshoot.

1. remove the belt start it up and eliminate the motor and mount

2. replace the belt (no blade yet) if you get vibration it is the belt, pulley alignment and/or lower wheel balance/bearings

3. put the blade on, tension it and move the guides all the way away from the blade, now the blade, upper wheel balance/bearings, tires and wheel alignment are in play


Based on what you have done I would bet it is bearings or pulley alignment, the latter most people gloss over but can cause exactly what you are seeing.

As for the blades I am not a TM fan (though there are lots here) I prefer Lenox bands either from a local industrial supply or Spectrum Supply. However, I doubt bands are your issue if it is more than one.

[bob hertle]

John,

The only time I've seen what you describe (intermittent cut+vibration) it was the lower tire slipping on the wheel. This was on a 20" DoAll at work. At high speeds the tire would actually separate and bunch up ahead of the pinch point. At low speeds it would slip on the wheel. Might be something to check out.

Regards
Bob

[John Coloccia]

I think it is time for the full troubleshoot.

1. remove the belt start it up and eliminate the motor and mount

2. replace the belt (no blade yet) if you get vibration it is the belt, pulley alignment and/or lower wheel balance/bearings

3. put the blade on, tension it and move the guides all the way away from the blade, now the blade, upper wheel balance/bearings, tires and wheel alignment are in play


Based on what you have done I would bet it is bearings or pulley alignment, the latter most people gloss over but can cause exactly what you are seeing.

As for the blades I am not a TM fan (though there are lots here) I prefer Lenox bands either from a local industrial supply or Spectrum Supply. However, I doubt bands are your issue if it is more than one.

Full update:

The sporadic cutting got a lot better with the new V-belt, and a lot of the vibration with the bottom wheel went away. I still have a touch, but it's pretty good for a 19" wheel :) I don't think it's the wheel itself or anywhere else in the drive at this point.

I'm looking at tires and wheels now. Honestly, I'm probably being too picky but I tend to keep my equipment as well tuned as possible. I can still pass the penny test with a blade on, even through startup, so I'm significantly better than the nickel test already. The only issue is that is was better and I want to get it back there.

I'll keep tuning throughout the week and let you guys know what I find. I want to get back to silky smooth.

[ian maybury]

Despite all the positive press i've had badly welded Timberwolf blade - no doubt it was a bit of an exception. The weld was flat, but the back (toothless) edge of the blade was not straight. (it made a concave 'v' of about 1mm in 300mm)

While it cut well it drifted badly. Holding a pointer against the back edge of the running blade you could feel an obvious 'kick' where the blade was advancing and retreating by quite a significant amount. (bouncing off the thrust guides)

The good blade that replaced it produced no detectable kick by the same means of testing....

ian

[Prashun Patel]

John-
What's the penny test and nickel test?
FWIW I hate tuning my bandsaw, and rarely get it exactly right. Too many variables for me.

[Van Huskey]

John-
What's the penny test and nickel test?
FWIW I hate tuning my bandsaw, and rarely get it exactly right. Too many variables for me.


Penny or nickel set on edge and you fire up the machine if it stays upright the machine "passes". The nickel is an age old test for machine vibration.

[Alan Schwabacher]

Have you checked that the pulleys are locked tightly on their shafts and properly aligned with each other?

[John Coloccia]

I think I'm narrowing it down to the tires. There are some rough spots on them. The bottom one is the original tire that came with the bandsaw and it's chewed up pretty well. I think I'll just replace them both (I have them on hand) and see where I end up.

I think it will end up being a couple of little things that added up to noticeable vibration.

[Mike Cruz]

User error, yup I think its user error. :D

Seriously, though, I am 100% with you on wishing there was a service for tuning up machinery. Most of my stuff is tuned up right now, but I would pay $300-$400 to have someone come in and tune everything up!