tension on bandsaw belt?

[James Baker SD]

Today I replaced the standard motor on my LT-18 (2002 model) with the 4.5hp Baldor upgrade. The motor runs a little faster than the original so the replacement pulley is a little smaller than the original, hence the adjustable motor bolt is not in the exact same place as before.

I squeezed the belt and it deflects about 1/4" inward on each side. I have no way of guessing the pounds of force I am putting on it ( Laguna manual says 10 pounds), but I am not real strong, so it probably is not much. Laguna manual does not say what the deflection should be, but the Italian multi-language manual says 5-6mm so I have about the correct deflection (but the force exerted is still an unknown).

When I tested the motor to see if everything is OK, I think I can smell rubber smoke; I don't remember this smell before. It is warm to the touch, not hot, but I only run it for 15 to 30 seconds in the early tests. Should I just loosen the tension till the smell stops, or run it a while and see if it goes away by itself? The saw seemed a little underpowered to me before the upgrade, so I don't want to lose power with a slipping belt, nor do I want to have to replace a burned up belt in the near future.

Thanks,
James

P.S. New motor is much quieter, first test cuts were really easy. Think I am going to like this.

[mickey cassiba]

Are the pulleys co-planar?

[Myk Rian]

Check the pulleys, and loosen the belt a tad.
Too much tension, and your bearings die an early death.
You want the belts loose enough to not slip.

[Salvatore Buscemi]

What do you mean by "the motor runs a little faster" usually motors run at 1140, 1725, or 3450. I noticed a big improvement in power transmission when I switched to double groove pulleys, and that was on a 1 1/2 hp saw. I was noticing the belt slipping on heavy cuts, not anymore. After experiencing that, I can't imagine a 4.5 hp motor pushing one rubber belt.

It would be nice to know exactly what you have on there, motor, belt and pulley wise.

Sal

[James Baker SD]

What do you mean by "the motor runs a little faster"
It would be nice to know exactly what you have on there, motor, belt and pulley wise.

Sal

The saw is a 2002 Laguna LT-18. It came with a 3410 RPM 3hp motor. The pulley drives a single V shaped belt. The upgrade was offered by Laguna. It is a 4.5 hp Baldor motor running at 3450 RPM (a little faster). Also in the upgrade kit is an adapter plate to mate the motor's mounting holes to the saw's holes and a new (slightly smaller diameter pulley. No replacement belt in the upgrade kit, so still the same single belt driving it.

To answer Mickey, the pulley's "look" coplanar to me, I will check again today. I measured the distance from the old motor's mounting surface and the center of its pulley. I duplicated this distance exactly from the new motor's adapter plate mounting surface to the center of it's pulley, so the new pulley is within 1/32" of being in the same location as the old.

Thing I did not do was to squeeze the belt before I took it off to see how much deflection my strength created so I am lacking a reference as to what it was when I could not smell anything.

James

[mickey cassiba]

I use a length of drill rod to check pulley alignment, 'cause that's what I have. I choose a size that'll lay in the 'v' of the pulleys. Mis-alignment will be instantly visible. Roll test your rod(or dowel) to ensure it's straight.

[Salvatore Buscemi]

The saw is a 2002 Laguna LT-18. It came with a 3410 RPM 3hp motor. The pulley drives a single V shaped belt. The upgrade was offered by Laguna. It is a 4.5 hp Baldor motor running at 3450 RPM (a little faster). Also in the upgrade kit is an adapter plate to mate the motor's mounting holes to the saw's holes and a new (slightly smaller diameter pulley. No replacement belt in the upgrade kit, so still the same single belt driving it.


James
Ok, I was worried you just went from a 1725 rpm to a 3450rpm. 3410 to 3450 is probably just a variation in how the horsepower of a two-pole motor (3600 rpm) is listed (just a guess). And it would only take an 1/32" difference in pulley size to maintain the same Surface feet per minute. So maybe the pulley size is just related to keeping the same belt size with the different motor mount.

So, it probably is just related to alignment or tension.

[mickey cassiba]

James, (and please realize that I'm not implying anything here) sometimes when folks make a major modification to a machine, a little part of their brain is 'expecting' malfunction. If the pulleys were not hot enough to burn your hand, I doubt that they were hot enough to burn a v-belt. You may have knocked off some belt residue when installing, and smelled the 'dust'. Belts wear, no matter how 'correctly' they're installed, and rubber dust is a fact of life. I noticed that you said that you had to use the old belt. Rubber dust, and smoke have similar odor. Maybe that's what you experienced?