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How to use Feickert Protractor on SME V Tonearm

I just bought a Feickert Next Gen Protractor. So far I just measured the spindle to pivot distance, it was set to 212mm. This is using a Denon DL160 cartridge setup using a paper protractor from the web. The spec for the spindle to pivot distance is given as 215.35mm. My turntable is a Gyrodec with mounted SME V tonearm. So I started thinking about how this would work using the Feickert protractor, each time I move the sliding mount of the SME V, I would then need to adjust the position of the sliding spindle to pivot distance of the Feickert protractor and thereby moving the alignment point. This seems like a never ending loop of adjust SME V slide adjustment, then re-adjust the spindle to pivot distance on the Feickert to get the correct alignment. Am I missing something, it seems like a very interative process to use the Feickert Protractor with a SME V tonearm. I bought the Feickert to make alignment simpler and more accurate. How do others use the Feickert Protractor to align the SME V tonearm cartridge?
hartonr

Showing 1 response by peterayer

peterayer
1,382 posts
 
As far as I know, SME did not assume anything about the cantilever length.
They assumed there would be an industry standard horizontal dimension
specification of 9.5 mm from the center of the cartridge mounting holes to
the stylus tip, regardless of the length of the cantilever. This is the
measurement that YIP at MINT needs to provide an accurate protractor to
customers who own SME tonearms.

I have precisely measured this distance on two of my cartridges. Fortunately,
they have the same mounting hole to stylus tip distance of 9.27mm so I can
use the same MINT protractor for both cartridges.

Yip needs this measurement so that he can calculate the pivot point to stylus
tip distance to accurately draw the currect radius for his arc protractor. The
offset angle of the headshell comes into this calculation as the radius is the
hypotenuse of a triangle formed by three lines: the pivot to stylus tip
(hypotenuse), the pivot to a point centered between the cartridge mounting
holes and the center point between the mounting holes to the stylus tip.

Once calculated accurately, the MINT protractor is an extremely good
alignment device.
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