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craftsman band saw vibration

true temper

Stainless
Joined
Jun 19, 2006
Location
Kansas
I bought a vintage craftsman vertical band saw yesterday. It vibrates bad running full speed, I think a big part of it is V belt problem. :mad: I have heard a twist lock adjustable belt will run smoother, any one had experience using them? :confused: Also it has a control box someone has added on it, it converts single phase to 3 phase. It has a 1/2 hp 3 phase motor on it. the control box provides variable speed to the motor. Its a neat way to control speed ,what would you call this?
 
My lathe ran much smoother after I changed from the original V-belt to a Twist-Lock from McMaster-Carr.

The vibration on the saw could be a build-up of cutting debris on the cast webbing around the inside of the wheels.

The rubber tires on the saw like to collect chips from cutting metal, too.

Roger
 
Any new belt will help for sure, twist-loks are good, I have used them for many purposes. Nice tohave a roll that you can simply go to. I would do a super cleaning job with a tooth brush on this, get the tires clean, bearings, motor etc. if you get a rythmic vibration, ie on thump per rotation, then you have a lump in a belt, tire, maybe a bad bearing on the driven wheel. If it is faster, then look furthur upstream towards the motor, ie the belt between the motor and drive, or the motor. The controller is a VFD
 
Very often the wheels are not truly round either. Have you taken a look at them? A small out of roundness can be very bad at operating speed.
 
First remove the belt, then run the motor. If the motor appears to run with vibration ,check the motor mounts and the drive pulley. Check the rubber on the wheels,the wheels themselves for balance. You can use tire strip weights if the wheels are not balanced instead of drilling rim holes.The belt might be bad, pulley out of alignment,or out of round. Last thing I can think of is a bad bearing, should be able to hear it .
mike
 
Thanks for the help, I am sure it is in the belt. The motor runs smooth with the belt off. The tire that the blade runs on is in good shape. Without the blade or belt the lower wheel is just a bit rough. I have heard of some kind of round belt that runs smooth don't know about them. Sounds like the twist lock belt and new bearings might fix it. What about the VFD controler is this a good thing? I have never seen any thing like this. Is it bad to run it real slow?
 
New vee belts are really inexpensive, like around $5. When you get a replacement belt, make sure it is a "fractional HP" rated belt, which is more flexible than the ones of the same nominal size rated for a full HP. If I had your machine, I would order a regular type of vee belt in the correct length, rather than switch to the twistlock type, mainly because it is easy to do.

The control box you describe is called a "variable frequency drive," or "VFD." There are numerous discussions on this site about these devices. The VFD will not be harmed by running slowly. A motor on a VFD will provide the same amount of torque at low frequencies as it does at 60Hz. So that means the motor delivers lower power (power=torque times rotational speed) at reduced speeds.

I am not experienced enough to say whether the motor will be damaged if you make the frequency too low. I imagine there is a little bit more danger of overheating the motor at very low speeds. I would try running the thing at 10 Hz and then see what happens...
 
Picked up a Craftsman 12" band saw on side of road for free, just needed a bearing for the lower wheel. Spun the shaft end for end as I remember to get a new surface for the needle bearings to ride on. Worked fine after that. Good luck, Jim.
 








 
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