Belt Replacement vari speed

[jlv3901]

I need t replace the vari speed belt on a JET verticle mill which is a cheap knock off of a bridgeport, I think. Anybody got the tip of the day on how to do this easily. I cant get the belt around the motor pulley with the motor set down. Any help is appreciated.

[widgitmaster]

On a Bridgeport, the motor had to be removed while the pully was attached!
The motor wiring was also too short and had to be removed from the switch box!
After the motor was removed, the top case had to be split in two, then the belt and all the vari-drive parts were exposed for repair / cleaning.
This can be done while standing on the machine table, and someone was needed on the floor to take the heavy motor!

Usually when the belt was worn, the bushings and plastic keys in the pully's were ready for replacement. This required a kit which came with a gizmo to align the bushing / key assembly during the glue up!

It has been my experience that the belts would wear out if the motor & spindle pully's were not adjusted for the propper maximum RPM, this would allow the belt to go beyond the outer diameter of the pully, and wear it out! The adjuster was located on top in front of the motor, and needed to be removed when the case halves were split!

To remove the spring loaded mechinism from the motor pully, required two pieces of threaded rod and some nuts to compress the pully and release the spring tension.

Now, I have never repaired the Chinese JET machines, but I have serviced several dozzen Bridgeports!

I hope this helps!
Eric

[Ben Colby]

Hello ,

You mention that the plastic key is "glued up". What does this mean?
I just replaced a vari-speed belt in my Alliant milling machine by the same
method as you described, but didn't glue anything. Was I supposed to glue
the key to the inside of the cone pulley or the motor shafts keyway?
or am I misreading your description?

Thanks
Ben
COBRO Mfg.

[widgitmaster]

If memory serves me correctly, the Bridgeport kits had a tube of epoxy to glue the bushings into the cones. The key had a round extruding boss which fit into a hole in the cones to keep it from sliding out. The key was not glued.

Widgit