I desperately needed to rebuild the countershaft on my Index 40H milling machine. It turned into an adventure in sand casting and turning v-belt step pulleys.
The specifications for v-belt pulleys I used are here: https://www.masterdrives.com/engineering/groove%20dimensions.pdf
If you like what I'm doing here and find some value in it, consider supporting my work on Patreon: https://www.patreon.com/Jeremymakesthings
I promise I'll still mostly make stuff out of rusty junk and not just buy shiny things with your money.