How to find the center of the spinner?

szicree · #1 03-20-2008, 07:44 PM

In order to have a wobble free spinner, I'm supposed to first find the very center of the tip. Is there some magical trick or do I just eyeball it.

mannanj · #2 03-20-2008, 08:19 PM

I clamped a marker (sharp point) to a ladder in front of my spinner, tried to find dead center on the nose of the spinner, then kept adjusting the spinner with cleco clamps on the aft side of the back flange, and moving the point until there was no runout. Somehow, (just dumb luck I guess!) I ended up with a spinner that's dead on!!!!!!

Ironflight · #3 03-20-2008, 08:33 PM

All I remember doing was lining the back edge of the spinner up with the rear of the flange on the aft spinner bulkhead and never checked for the center of the nose. No wobble that anyone has mentioned seeing - I guess I was lucky as well!

Paul

Geico266 · #4 03-20-2008, 08:44 PM

We used a dial indicator on the end and get them within .005 on a side.

jthocker · #5 03-20-2008, 09:01 PM

5 times with Paul's method and my eyeballs, 5 times wobble Free!

Martin Sutter · #6 03-20-2008, 10:17 PM

The trick is to position the front and back plates so that the spinner contacts both at the same time when pushed against them. This can be done by adjusting the number of washers under the front or back plate. Once the position is correct the spinner is centered automatically.

You can tell when they are in the correct position when the spinner cannot be moved sideways while being pushed against the bulk heads.

On a fixed pitch prop installation you might have to use a shim under the front or back plate instead of the washers on the C.S. props.

Martin Sutter
building and flying RV's since 1988

az_gila · #7 03-20-2008, 11:54 PM

Quote:

Originally Posted by Martin Sutter

....
On a fixed pitch prop installation you might have to use a shim under the front or back plate instead of the washers on the C.S. props.

Martin Sutter
building and flying RV's since 1988

...or buy the metal Sensenich spinner assembly that comes pre-drilled with all of the nutplates installed...

gil A

Kahuna · #8 03-21-2008, 04:46 AM

This is a cheap easy method, tested many many times.
Details here:
http://www.mstewart.net/michael/rv/s...er/spinner.htm

sportpilot · #9 03-21-2008, 05:29 AM

This just in from the Easter Beagle.

To find the center take a small piece of alum thats good and flat. Smear a tiny bit of paint in the center. Hold the piece up to the spinner and line it up best you can sqaure on to the axis. Push the piece up against the spinner tip. That will leave a tiny spot of paint right at the apex. If that aint the center I dont know what is.

To check for wobble, tape your long #40 drill bit to something that will keep it at the same height as the paint dot. (step ladder works good). Turn the blade thru and watch the drill bit and the paint dot as they dance up and down. Adjust the spinner till you get it right. Clamp it good before you start to drill. The funny part is you wont know how good a job you did till you fire it up.