Help with Bandsaw stalling out

[Phillip Mitchell]

I just bought a used, mid 80s era, 20" Italian bandsaw made by Steton (not very well known in US, but quality industrial machines similar to SCMI)

I'm able to stop the blade way too easily during a light to moderate re-saw cut. 5 1/2" tall Doug Fir and Western Red Cedar (dry) is what I was sawing....shouldn't be giving me these issues with this species and size. Even with a very slow feed rate, the saw blade will still bog way down and stop completely. I stop feeding stock and it will catch back up to regular speed in about 5 seconds.

I am smelling a faint burning rubber smell. I didn't think to note if the actual motor was slowing down with the problem or just the blade. Will have to try again to confirm. From my memory, it seems like the motor is still running while the blade bogs and stops.

The drive belt looks old (original ?) I don't really know exactly how much tension should be on the belt, but my gut tells me that it's too loose. More deflection than the Laguna LT18 sitting in the next room, when I check it's tension by feel.

Brand new 1" blade. 2 hp, 220V motor. Before I bought the saw, I had a feeling I may find the motor a bit underpowered during heavy re-sawing, but this isn't even approaching heavy re-sawing... The previous owner told me he replaced the rubber tires somewhat recently.

So, what would be my first course of troubleshooting action?

Tighten the belt? How tight? Replace the belt? How do I properly size and find the correct replacement? There is practically no dealer support for this brand and age of saw. I actually have the original manuals for the saw but they are in French and Italian.

Thanks for any help and advice?

[Jon Fletcher]

I would check blade tension first. If blade tension is ok then check the belt. From what you describe the way the motor takes 5sec to catch up it my be wired wrong or a bad motor. If the belt is slipping and getting burnt you'll see material on the pully where the belt rides in the groove. As for tension I believe just the weight of the motor should be enough. I can't imagine 2HP not being enough but then again, I dont do much resawing.

[Rod Sheridan]

As Jon indicated check belt condition for glazing or burned sections. Honestly I would replace the belt if it's old. Take it to a power transmission dealer and they'll measure it for you, and provide the correct bely

Check that the pulley is tight on the motor shaft, clean both pulleys

Verify that the motor is the correct voltage, and that you have the correct voltage by measurement.

Regards, Rod.

[Nick Lazz]

If the tires are good and you have decent tension on the blade I would look at the motor. I had a situation with my Laguna saw years ago from the factory where claimed HP was an absolute joke. They called it 'Saw Duty'. After calculating the actual HP they were off by nearly 1 HP. I got them to replace the motor.
Granted, my saw is smaller than yours but I have a 2hp motor on my Laguna 14SE saw and I can't run 1" blades. Tension may have been a bigger problem for me but power was as well with the original motor...seems 20" should have no problem tensioning that blade.
P = V(volts) x I(current) x Eff (efficiency) x PF (power factor)

[Grant Aldridge]

just to cover all the bases on machine setup, you do have thrust bearings adjusted properly right? I could imagine rearward deflection causing this.
As has been said make sure you have blade tension set correctly, also you said it's a new 1" blade but is it a resaw blade? A finer toothed blade could also cause this.
Last, have a look at the motor and cord wiring, something could be out of whack there!

[John TenEyck]

Another possibility could be that the run capacitor on the motor needs to be replaced. That happened on my J/P.

John

[Jack Frederick]

How about dirty/burned tires on the wheels. If there is burning or accumulated debris the blade can slip on the tires.

[John C Cox]

My 14" saw has a 1 1/2 hp motor from the factory.

I doubt a 20" resaw comes equipped with a 2 hp.... I would expect at least 5 hp.

First thing.. Find the saw's name plate. It should list the specs for the motor... Probably in KW... Convert to HP and go from there.

Next thing though. Check to make sure the motor is wired correctly. It should have a wiring diagram inside the motor cover for the various voltage configurations. Make sure you are giving it what it's supposed to be wired for.... For example - it could be that it's only running on 1 leg of the 220... It will kinda run - but it will destroy the motor in the process.... Or it could be wired internally for 3 phase 208 and you are trying to run it on 2 phase 220...

[John K Jordan]

Besides the obvious electrical issues to check... How many teeth per inch on the blade? Too few and the gullets can't clear the sawdust fast enough and the blade may quit cutting or get jammed up, depending on the wood.

Is the blade tensioned enough? Too little tension can cause major problems. I use a 1/2" 3 TPI blade an check the tension with a gauge. The factory tension marks are not useful.

For a new belt you can measure or take the old belt with you. If the old belt has numbers printed on it they may be able to cross-reference. The local NAPA stocks standard belts to fit almost anything. A link belt can be adjusted for length by removing links.

[Phillip Mitchell]

OK, thanks for all the responses. Let me try and respond to some of these.

I don't have a tension gauge, but am familiar with how to tension a blade. There is between 1/8-1/4" deflection on the blade with sideways pressure and the guides set at around 6" off the table. The 1" blade currently installed is 2 TPI. I have a new 3/4" 3 TPI blade as well, so I will install that and give it a try to see if the 2 TPI blade is the problem.

I have the original manuals for this saw, which states that the motor is 1.5 KW (2 HP according to a conversion from Google.) The original motor was replaced with an 2 HP Century motor (American made) at some point in its life. Nowadays, a 20" saw wouldn't be sold with a 2 HP motor, but back in '86 I don't think that was too uncommon as motors tended to be smaller in general than they are with today's new bandsaws.

I tested the saw and made a handful of cuts before I bought the saw and didn't have any issues. There was a 1/2" blade installed when I tested it initially, and re-sawed a 6-7" tall piece of white pine with no issues. Granted, white pine is about the easiest wood to saw, but Doug Fir and WRC shouldn't be difficult. Maybe there's something to the 1" blade, not having enough TPI? The saw was plugged into regular 220V receptacle at the sellers shop.

Could running the saw without dust collection (just for quick test cut) cause enough sawdust to fall down and settle on to the rubber tires of the lower wheel, get between the blade and tire and cause this sort of slipping?

I'm still getting used to these Euro style guides, but to the best of my knowledge, I'm setting up the guides properly. For setup, I'm running the thrust bearing up against the back of the blade, then backing off of it the thickness of a folded dollar bill and locking it down in that position.

I can't speak directly to the other replies, as I haven't had the chance to get back and test the saw out. Will update as I'm able.

Thanks again for all the advice. Keep it coming!

[Brian Henderson]

You need to figure out where the problem lies, is the blade slipping on the wheels, is the motor slipping or bogging? It could be as simple as blade tension or bad tires or as serious as an underpowered motor. You might want to run the saw with the door open just to see what's turning and what's not.

[Jeff Duncan]

1st thing I'd check is the blade, even if new could be defective! Belts aren't that tough, something in the neighborhood of 1/2" of deflection for something that size under moderate pressure should be fine. Is the 220v single or 3 phase?

2hp for a 20" is not really under powered, we just think it is in here in the States. My 20" saw is 2hp and is only about 20 years old.... as long as the blade is sharp I have no problems cutting up to 12".... the key being good sharp blade. HSS blades don't last all that long if your cutting hardwoods, the softwood you mention should likely last quite a bit longer, but still not uncommon for folks to keep pushing long past blade change time.... guilty if this myself from time to time

good luck,
JeffD

[Grant Aldridge]

Since it worked at the sellers shop you really need to check voltage at the motor. The cord could be wired differently than your receptacle

[Lee Schierer]

I am smelling a faint burning rubber smell. I didn't think to note if the actual motor was slowing down with the problem or just the blade. Will have to try again to confirm. From my memory, it seems like the motor is still running while the blade bogs and stops.

Tighten the belt? How tight? Replace the belt? How do I properly size and find the correct replacement? There is practically no dealer support for this brand and age of saw. I actually have the original manuals for the saw but they are in French and Italian.

Thanks for any help and advice?

When I first started using my 14" band saw thought it was under powered as I could do the same thing. I had read a lot about 14" Delta saws being under powered. When I finally watched what the motor was doing when the saw stalled, I found the motor was still running at full speed and the problem was the belt tension. When I tensioned the belt, the saw was an entirely different machine. It walked through the same cuts that had bogged it down with out even breaking a sweat.

Tighten your belts and you should be good to go. If the existing belt is old it would be a good idea to start looking for a replacement before you really need one.

[Mike Henderson]

Is it a single phase motor or a three phase motor? If it's a three phase motor you would have something to convert from single phase to three phase - unless you have three phase power in your shop.

If it's a single phase 240V motor and that's what you have going into it, I'd next ask if the motor is slowing down or if it's still running normally while the blade is stopped.

If the motor is running, first thing I'd check is the belt driving the lower wheel (from the motor to the wheel). If that's slipping, replace the belt and clean the pulleys.

If the motor is stopping, I'd start checking whether the motor is wired for the voltage you're putting into it. If it's wired correctly, check the run cap (if you have one).

2HP should be enough for that saw.

Mike