Ortofon RS-309D or similar tonearm owners...any trick to finding pivot point from above?

I'm aligning my cartridge on an Ortofon RS-309D with a Feickert protractor, but the pivot point on the tonearm is not marked. My approach to finding it is...I put a small piece of painter's tape on top of the bearing housing, then I use an INCRA precision centering rule to find the center of the housing in both dimensions. The resulting X marks the pivot point. It seems to work. When I move the tonearm with the Feickert pin over the point, the X center stays centered under the pin.


I'm wondering if anyone has a better method for finding the pivot point for the purpose of using the Feickert protractor.




I got the same situation with my Polestar tonearm. Here is my method to find the center point:

1. Put a piece of paper tape over the cap of the tonearm where the center is

2. Replace the center pin of the Dr. Feckert by a piece of lead taken from a pencil.

3. Locate the pencil lead on top of the paper tape about 5mm from an estimated center. Let the lead touch the paper tape.

4. Rotate the tonearm cap bay moving the headshell. The pencil lead will draw an arc on the paper tape. 

5. The center of the arc is also the center of the tonearm pivot point.