On 09/10/2013 08:46 PM, Tom Gardner wrote:
On 9/10/2013 11:05 AM, Pete S wrote:
Maybe a small point, but having the set screws opposite each other would
be the worst way to use set screws, wouldn't it? If you have to use
two of them, shouldn't they be 90 degrees from each other so they are
both pulling the part toward the same side of shaft?

Pete Stanaitis
---------------
"Tom Gardner" Mars@Tacks wrote in message
...
I have an application where a 1" dia. shaft is hard to R-62 and a part
is attached with two opposing 3/8" cup-point set screws. The part has
a cam follower on it and rotating the part on the shaft then locking
it with the set screws is a positioning adjustment. There is about 75
pounds of force on the part. I hate this set-up! I just don't trust
it not to slip but I can't think of a better way of locking the part
on the shaft yet be able to adjust it easily.


Yep, but no room at 90. I figure that oposing is better than 1 screw.

No. The action of the set screw pulls the opposite side of the part
against the shaft, and that is where most of the torque resistance comes
from, not from the screw itself. Two screws at 90 degrees assist each
other in pulling the part against the shaft. But, two opposing set
screws will fight each other. The part is not pulled against the shaft
anywhere, and the tiny tips of the screws are doing all the work.

Opposing sharp point set screws digging into a soft shaft might behave
the way you expected, but that's not what you have.

--
Bob Nichols AT comcast.net I am "RNichols42"