Drill Press Pulley Vibration Issue

[jonhdw]

I have an old Boice Crane 2600 Helmet Head drill press that has a vibration issue on the drive pulley.

I isolated the issue down to the motor/pulley, and thought it might have been the motor bearings since it vibrated without the pulley. I replaced the bearings, and the motor now runs really well, but once the pulley is installed, the vibration reappears. I think the issue is due to some damage on the motor output shaft causing poor fitment between the shaft and the pulley. This throws the pulley out of alignment (which probably also killed the original bearings).

It's not the original motor, and it's not even the right frame motor for that drill press but it fits OK. So I'm not opposed to replacing the motor, but I was wondering if there is a good way to fix the output shaft or at least figure out a good way to mount the pulley on the damaged shaft so that it is perfectly centered and balanced.

Any ideas? Thanks!

 

[larry_g]

First check that the motor shaft is straight and has no runout. If it checks good then the pulley can be bushed to fit.

lg
no neat sig line

 

[Maui]

Some photos would help here.

 

[seber]

I would think it more likely that the pulley is damaged.

 

[Stillgottimefor1]

This may sound like a knee-jerk answer, but many folks on the hundred miles long (but great) craftsman drill press thread have found that the belt takes a “set” from sitting in one position for years on end much like a tire develops a flat spot from sitting on a garage floor and resists turning manifested by a flopping sound and vibration. Try a new belt before going crazy looking for a different problem.


Sent from my iPhone using The Garage Journal mobile app

 

[OccupantRJ]

Also, if the pulley is aluminum I have seen a lot of problems with them getting loose and wallowing the bore crooked.

 

[jonhdw]

First check that the motor shaft is straight and has no runout. If it checks good then the pulley can be bushed to fit.

lg
no neat sig line

Thanks, the shaft is straight, but mangled, so the hole through the pulley is slightly bigger than the shaft. The pulley is dead on 5/8"ID. I think what's going on is, there's only 1 set screw on the pulley to secure it and since the shaft is slightly small, the set screw pushes the pulley off of concentric, and a slight angle to the shaft center line.

Can you elaborate on how the pulley can be "bushed"? That sounds like what I need to do; get a good pulley centered and plumbed to a bad shaft. Thanks!

 

[454ragtop]

You could try putting a shim between the pulley and the shaft, had to do that once, worked good. If you don't have any shim stock, try cutting up a beer (or soda) can, they're pretty thin and flexible.

Edit to add, I wouldn't be comfortable bushing a good pulley bore to fit it to a mangled motor shaft, now you have 2 parts out of spec.

 

[2oolhound]

The shims are a good idea. I'd be tempted to spin the motor up and hold a fine file on the shaft to true it up and smooth it out too, then shim.

 

[jonhdw]

So I ended up adding three set screws to the pulley spaced 120 degrees apart, then truing it up with a dial indicator. It’s not perfect, but it’s about 90% vibration free now. I tried the shims but they were too thick and didn’t stay in place very wel.