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Help removing variable speed pulley on Taiwanese 3HP milling machine motor

nt1953

Hot Rolled
Joined
Sep 4, 2004
Location
Huntsville, Alabama
I want to replace the motor bearings on the Taiwanese clone (Bridgeport) that I am doing some refurbishment on, but I cannot figure out how to remove the fixed part of the pulley and the motor shaft adapter.

The motor appears to have a sleeve on the shaft that increases its diameter and provides the surface and diameter required for the movable part of the pulley. I assume the fixed pulley is a press fit to the shaft adapter, and they may both be a press fit to the motor shaft.

There is no visible keyway or set screw, but there is some sort of pin in the adapter (shown in one of the pictures) that is not centered in the hole it may or may not have been inserted through. The pin does not appear to be in far enough to allow the shaft adapter to clear the pin if you attempt to pull the adapter off of the end of the shaft.

I applied some moderate force in an attempt to pull the shaft adapter/fixed half of the pulley off of the motor shaft, but nothing moved and I do not want to warp or break anything.

I am considering drilling a hole into the pin to see if I can pull it out, but I would have to machine out the hole to make the hole and pin align.

The motor is s Jin Shin 3HP.

Does anyone out there have any experience with removing these parts from a motor like this?

IMG_20220109_133536[1].jpg IMG_20220109_133558[1].jpg IMG_20220109_133612[1].jpg
 

crickets

Hot Rolled
Joined
Jul 3, 2021
It is very unlikely these parts are a press fit. Usually they're sliding fits with tight tolerances. Even then, I've certainly run into a problem before where a shaft extension wouldn't budge from a motor shaft even with extensive heating and a 5 ton hydraulic puller, even though nothing was holding it.

I haven't run into the specific parts you have in the picture, but there is a chance that pulley has two diameters, smaller being towards the motor. So pulling it like that you may also be pulling the sleeve.
 

dalmatiangirl61

Titanium
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
There is no visible keyway or set screw, but there is some sort of pin in the adapter (shown in one of the pictures) that is not centered in the hole it may or may not have been inserted through. The pin does not appear to be in far enough to allow the shaft adapter to clear the pin if you attempt to pull the adapter off of the end of the shaft.

I am considering drilling a hole into the pin to see if I can pull it out, but I would have to machine out the hole to make the hole and pin align

I'm thinking that pin is the problem, might be wrong. If the pin does not go thru to other side where you can drive it out, then maybe drill and tap it, screw bolt in and pull.
 

Tony Quiring

Titanium
Joined
Nov 5, 2008
Location
Madera county california usa
Looks like a pin...

Puller location will wipe out your part.

Get pin out then only small amount of torque on puller, if needed make a backing plate that fits behind pulley and pull against it

Sent from my SM-G781V using Tapatalk
 

rons

Diamond
Joined
Mar 5, 2009
Location
California, USA
If you tap the end of the bar and the pin moves a little in the hole, you know it is has to be taken out.
Drill, tap, pull. You can make another pin later. You will find out if the pin is straight or tapered.
 

nt1953

Hot Rolled
Joined
Sep 4, 2004
Location
Huntsville, Alabama
After very careful examination; looking in the "pin hole" and at the bottom of the hub; I decided that what little I could see in the hole in the adapter bushing might be milled for a key and I could see what I thought might be the bottom of a keyway (only about 1/64" showing) below the hub. So, I decided to modify some 3/4" plates so that they had a notched cutout with a 1/4" lip that would fit under the pulley hub and a wood box to hold the 3/4" plates and motor up high enough to fit in my press.

A bit over 5 tons later, the pulley is off and I do not appear to have damaged anything.

The rounded end of the key and the hole in the adapter bushing threw me off and made me think what I was seeing was a pin.

Thanks to everyone for their assistance.


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