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Hiya folks,

Just for clarity and posterity, I've measured the drive pulleys and feedscrews for both my "early" Q and my "late" Q. As I indicated in the post I linked above, the geartrains remained unchanged between the two versions of Qs I examined.

The following are their respective dimensions (early ----> late).

Pulleys:
0.827" ----> 1.077"

Feedscrews:
5/16-48(?) ----> 5/16-40 (My thread gauges don't go smaller than 40 TPI - so I consulted my Machinists Handbook to guess at the next finer thread possibility.)

I'd be very interested in others' results.

Best,
Fran

Thanks for the correction, Fran!

I clearly "misspoke" ("mistyped?") when I wrote that Q feedscrews are 100 tpi. It's the records that are 100 tpi. Whether the feedscrew is a fine one found on Edison Triumphs, or a coarse one supplied with an Edison Standard, or 40 tpi as seen on the Q, the mathematical combination of gear teeth, pulley diameter, and feedscrew pitch must equal 100 tpi for most pre-1908 phonographs.

George P.