Cutting down a motor shaft.

Sometimes you need to cut down a shaft on a motor to fit into the available space. This can be done in several ways, most commonly using a carborundum disc in a mini-drill. The shafts are usually hardened steel so most files and saws won't make an impression. As I once wrecked a Mashima 1220 using a cutting disc I decided that it might be wise to find a different method. The problem with using a cutting disc is that it generates heat, which in my case melted part of the plastic motor housing and left a bearing hanging loose. So here's how I do things now:

First job is to wrap up the motor in masking tape, to prevent any filings getting inside;

This is particulary important in this case as I'm using an open framed motor.
I've made a mark where I want to cut. Then a 3-sided diamond coated needle file is used to cut a groove around the shaft;

When the groove is deep enough the end can just be snapped off with a pair of pliers. Finally the cut end is cleaned up, again with the diamond file;

Job done.

Apart from not creating heat, which might damage the motor, this method also has a couple of other advantages. Firstly any mess is contained in a very small area, no sparks or dust flying around. Secondly it saves me the effort of digging my seldom used mini-drill out from the back of the cupboard.

Now I know that there will be a lot of folk thinking 'well I've been using a 9" angle grinder for cutting tiny motor shafts for the past 30 years with no problems', which is fine, but I'm just putting forward an alternative method. My way is not the only way, just something that works for me.

Paul.