Actually, you can get by without the bevel gear. My prop pitch has a
horizontal hole through the splined shaft down inside the splined shaft
about 2 inches. This hole was always there as part of the manufacturing
process. There is an access hole in the prop pitch casting. I installed a
hard metal pin about 1/2 inch in diameter through this access hole and into
the hole in the splined shaft which is held in place by a couple of small
screws and a couple of large flat washers. The 1/2 inch pin is drilled and
tapped on its flat end surface on both ends to accept the small screws. The
flat washers keep the pin from sliding back an forth. My two inch OD mast
is notched on the bottom to slide over the pin. The ID of the splined part
of the prop pitch is larger than 2 inches so I had a friend of mine with a
lathe make me a special aluminum spacer that just slips over the outside of
my 2 inch mast and just inside of the splined prop pitch part. Gravity
holds the mast and the spacer in place. This system has worked well since
1975 turning a 48 foot boom 5 el 20.
For a direction indicator, I use a pair of selsyns and they are linked by
bicycle chain to the 2 inch mast. This has worked well since 1975 also.
----- Original Message -----
From: "GALE STEWARD" <email@example.com>
To: "towertalk reflector" <firstname.lastname@example.org>
Sent: Monday, June 03, 2002 5:06 AM
Subject: Re: [Towertalk] Prop-Pitch
> My PP is mounted to a modified Rohn rotator mounting
> plate. I took it to a machine shop and had them cut a
> larger center hole in it. Think it 5 or 6 inch
> diameter. You DO need the bevel gear to make any type
> of coupling to the mast. I used an output shaft and
> clamp assembly from a trashed Hygain RotoBrake 400.
> I need to get up my tower with the digital camera then
> I could post some pix.
> 73, Stew K3ND