Re: Terry - "Improved" propeller gap design

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mark Broker by way of Terry Fritz <teslalist-at-qwest-dot-net>" <mbroker-at-thegeekgroup-dot-org>

If the "clamping slot" is made through the entire length of the
hub, then no fancy machining process is needed - only a hack saw.
I see no real advantage to using such an elaborate design.

As for set screws:  FWIW, I used 4-40 round head machine screws
as set screws on my standard rotary design.  A #21 hole was
drilled through the center of the bolt using a lathe, in which
the 5/32" tungsten was insterted.  I couldn't remove a tungsten
rod if I had to without loosening the screw, even after many long
runs and months of sitting in the closet.

Mark Broker
Chief Engineer, The Geek Group


<snip>

 >Seriously, I had come up with a design improvement similar to
your
 >suggestion of using a split shaft-collar to secure the tungsten
rod.
 >Instead of using a shaft collar captured in a slot in the hub,
why not just
 >make the hub itself have the split-collar clamp built in?
 >
 >See the attached Word file for a crude drawing of the concept.
 >
 >http://hot-streamer-dot-com/temp/Improved%20propeller%20gap.doc
 >
 >Unfortunately, this requires not only a lathe and a milling
machine, but
 >also requires that the slot for the split-clamp be plunge -
EDM'd. This is
 >really not too expensive to have done, but does require that you
to have an
 >EDM shop in the neighborhood.
 >
 >
 >Regards,
 >Scott
 >
 >
 >