On Nov 1, 5:15*pm, Marty Escarcega wrote:
John Martin wrote in news:007004e0-fe91-4ccc-a685-
:





On Nov 1, 3:47*pm, "Martin H. Eastburn"
wrote:
I have an old - well it was bought new in 35 by a friend :-)
He was into audio - home made amps and needed one.

The double shaft allows for a flex shaft that Delta sold.
Dad had one from the 40's and sometime in the late 90's it
finally bit the dust. *Internal flex shaft broke. *It was used
to wire brush stuff or polish with a cloth buffer.

Martin

Are you saying that this was meant to be used with the toolmakers
grinder?

While the bump-out in the casting accommodates the double shaft motor,
there does not appear to be any way to hook up to the shaft. *If you
put a flexible shaft on it, you'd have to drill a hole in the
casting. *If you put a pulley on the shaft, you'd have to have the
driven pulley below it - and there doesn't appear to be a mount in the
casting for such an accessory.

Marty mentioned balanced motors. *I'm not sure that these were
balanced. *The literature mentions that the pulley and motor were
balanced as a unit - implying that the motor itself was not balanced
to begin with, and that it was corrected by using an out-of-balance
pulley. *Maybe I'm assuming too much, though.

John Martin

According to the user's guide it states "Operate grinder with a good
dynamically balanced motor only"

A couple of us are trying to ditch the V belt drive in favor of a flat belt
drive...

Marty- Hide quoted text -

- Show quoted text -

I may have been wrong about the motors. I had recalled seeing
someplace that the important thing was to balance the motor and pulley
together. To me, that implied that if you started with a motor that
was not perfectly balanced, you might bring it into balance by
drilling the pulley. I'm not sure that would bring it into perfect
dynamic balance, though.

Here's what the Operating Instructions (PM-1628, dated 4-15-60) say:

"To insure the maximum efficiency of the Delta Surface Grinder, it is
offered complete with a motor. The motor, motor pulley and spindle
pulley are each independently dynamically balanced. In addition when
the spindle is being "run in" and the table ground, the motor and
motor pulley as a unit are balanced, and this unit is then shipped
with that machine.

It is IMPORTANT therefore that the motor pulley and motor are not
separated. If the motor or pulley requires replacement or repairing,
return both items to the factory so that they can again be balanced as
a unit.

It is possible that other motors which are properly balanced might
give satisfactory results, but because of the importance of good
balance between all operating parts of this type machine, we do not
recommend using other motors or pulleys and cannot be responsible for
results obtained."

John Martin