I was reading threads here by Bill Mayo and others about switching to a link belt. I have a green one of unknown origin that I just measured for width and it's right at 0.543". Out of curiosity and to compare, I dug out a couple of used belts I had in a box. Both were Pirelli (the printing varies slightly from the one above but the text all reads the same). One was on my Greenie when I acquired it several years ago, the other was a spare that came with it. One measured 0.544" and one 0.542" (13.8mm and 13.7mm, respectively). I suspect they started at 14mm. (And Steven above has a math error -- 50mm is just shy of 2". By "mm" I'm sure he means "1/1000in". I.e. 0.50" and .048").
EDIT: I think the green link belt may have come from Harbor Freight. To match the 26.5" outer circumference of the Pirelli requires 31 links
IMG_9825.jpeg (418.91 KiB) Viewed 8165 times
Greenie SN 362819 (upgraded to 520), Bandsaw 106878, Jointer SS16466
I've installed the link belt. With it, I get RPM from 500-5000 (+/- a few tens of RPM).
This is the belt that I installed on the machine last year, brand new from Shopsmith. It's 0.49" wide. I felt like with it, the speed control was non-linear at the slow end. It seemed like from "slow" up to about C or D, changing the control didn't do anything. Also, it was noisy at the slow end. With the link belt it feels more linear and is noticeably quieter.
IMG_9827 (1).jpeg (333.69 KiB) Viewed 8137 times
Greenie SN 362819 (upgraded to 520), Bandsaw 106878, Jointer SS16466