On Thu, 01 Dec 2011 17:11:55 -0800, wrote:

I am forever looking for a better way to finish small parts. I have
been looking at buffing machines and the first thing that struck me
was the price discrepancy between them and comparable size bench
grinders.

Whereas I can get a 1/3HP bench grinder for $40, a no-name buffing
machine of the same power is $105. If one goes up to, say, Baldor, one
is lucky to see any change from $300.

Why is that? Is it a bearing issue? Why would a $40 bench grinder not
be able to do the same job as a more expensive buffer?

Michael Koblic,
Campbell River, BC
Greetings Michael,
I have converted several grinder motors to buffers. This usually
just involves removing the grinding wheel and slipping a buffing wheel
arbor over the motor shaft. However, some of the adapters run out a
lot and so need to be bored and sleeved. Also, sometimes the part you
will be buffing will bang into the grinder motor so the buffing motors
have longer shafts and often the shafts are a larger diameter. I
haven't let this deter me though. I have converted a few 1/2 hp
grinder motors to buffer motors by removing the rotor from the motor
and lengthening the motor shafts. The shafts were lenghtened by
cutting smaller O.D. threads on the motor shafts than what were there
originally. So for a 1/2 dia shaft the thread would be 3/8. I then
turned the motor shaft smaller by about .06 for about .500 past where
the thread ends. Then a shaft extension with a 3/8 thread and a
counterbore is threaded onto the motor shaft and secured with Loctite.
Finally the extension is turned so that it runs true and the motor is
re-assembeled. I support the motor shaft in a steady rest in order to
centerdrill the extension and then use a live center to support the
shaft for final turning. This method has worked very well for me. I
only add about 2 inches to the original length though. With the
tapered buffing wheel adapter in place the overall extra length is
about 3 inches. It's really not that time consuming to do the motor
work and if you have the time and not the money it pays. It's also
good practice on the lathe.
Eric