DIYbanter - View Single Post - Rockwell 6" bench grinder - anti-rotation pins

Joseph Gwinn

In article ,
wrote:

On Mon, 05 Mar 2012 20:59:53 -0500, Joseph Gwinn
wrote:

In article ,
wrote:

On Mon, 05 Mar 2012 08:21:09 -0500, Joseph Gwinn
wrote:

In article ,
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote:

Stanley Schaefer fired this volley in
news:9f7cc9e0-
:

So I
think your arbor is overengineered unless it was intended for driving
some other gizzy

I'll agree, and go further with that thought.

Spiral pins are easy to remove (as opposed to roll pins).

Yes. These were roll pins (look like a fat letter C, not a two-turn
spiral). There wasn't enough left to grab and pull the pin stub out.

There is no apparent reason for that pin to be easily removable, unless
it's intended to be removed.

I agree with both of you, but still Rockwell went to some trouble and
expense to put those pins and key slots in, so they must have thought it
necessary or at least quite desirable. The question is why. What
problems were they solving?

Joe Gwinn
Greetings Joe,
I think they were just avoiding a shoulder on the shaft. And since
they were using a pin and cast washers why not cast in slots for the
pin?

The shaft has a substantial shoulder, upon which the big flange washer
rests. The pin is in a machined keyslot, and does not prevent motion
along the shaft. Only rotation is prevented, and only for the two inner
flange washers (nearest to the motor).

I suppose they could have cast the slot in, but they didn't, and they
use only one of the two keyslots, so my guess is that they simplified
the attachment but left the washers alone because they already had the
molds and tooling.

Joe Gwinn
Well then I'm stumped. If the pins only prevent rotation then maybe
some engineer though it was a good idea. I have never seen a grinder
like this and have never needed a pin to prevent wheel rotation

But that engineer had to convince his penny-pinching boss to spend the
money. Not to mention the boss's boss. They had to have had a reason.

Joe Gwinn