The photo of the Feickert may lead you to believe that I’m clueless as to it’s use, but rest assured, there’s a method to my madness.
I’m a big fan of arc protractors in general, and the Mint LP in particular, but I’ve come to rely on the Feickert protractor for both quick and easy setting of pivot to spindle distance as well as for its universality.
Some tonearms will challenge you, irrespective of your chosen tool however …
Tonearm designers are a quirky lot, and their designs reflect this. Sometimes you need to get crafty to develop a workaround.
One such challenge lies in locating the bearing pivot on the Jelco tonearm. Some arms, like the Shröders and Kuzmas add a reference mark or other indicator which allows you to locate the bearing pivot. The Jelco does not.
I went through all sorts of machinations – initially working to fabricate a jig to position the tonearm. For reasons too detailed to explore here, the project got out of hand and I changed my strategy.
I switched tactics and placed some masking tape on the bearing tower in an attempt to establish the center by drawing two diameter lines. Their intersection would be the center. This is harder to do then it appears, and after several tries, I realized that this wouldn’t produce reliable results.
Then, a lightbulb went off. That disk on top of the bearing tower (defined by the ridge line) is 30mm in diameter.
With a 214mm pivot to spindle distance specification, I set the Feickert to 229mm (214 plus the 15mm radius of the circle). It was then a simple matter to find the “peak” of the circle (the most distal point from the record spindle) to ensure I lined up the Feickert correctly.
Obviously, this won’t work with all arms, with the Ikeda being one exception. Every situation is slightly different, but this is a technique to carry in your arsenal.