Note the extended point set screws are better and easier to machine than splines. All back lash is eliminated.

Paul Lamar


Hi Paul, can you give an overview on the " Note the extended point set screws are better and easier to machine than splines. All back lash is eliminated." I am not familar on this topic.

Thanks, Steve Carlisle

A spline (properly machined)  is proud of diameter 1.
The inner shaft is the  highest stressed part. So for max strength
it should be as large as possible.  There is a shear stress concentration
at the start of the spline and near  the root of the spline.

You can make the shaft larger diameter  with thinner wall say diameter 2 if you
use set screws. The shear stress is then distributed over the number
of screws you use.

Of course it  much much easier to machine with no broach
or mill required. Especially the female part. I know no
way of doing a female spline  with out a shaper or broach.

Just a drill press and taps are all that is required for extended point
set screws .

Tightening down the set screws removes all slop and back lash.


BTW always sign your last name as we have many Steves on here :)

Paul Lamar


Okay Paul, where in Tracy,s re-drive would you be able to use those screws .

Steve Carlisle


 Do I detect a  doubting  Steve ? :)

Since the pin fixing the input shaft to the sun gear failed twice THAT
IS WHERE THEY ARE SORELY NEEDED :) You will need 8 or 12-- 3/8-24.

Paul Lamar

The Rotary Engine News Letter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
You Tube http://tinyurl.com/beqqxas
Copyright 1998-2014 All world wide rights reserved.