The screws used in the earlier Johnson rope sheaves are 10-30 screws. My South Bend lathe has no setting for cutting 30 threads per inch. My Cardiff does, but I don’t have the necessary headstock gear for it. I bought a 10-30 die from a place in Michigan for 11 dollars US. I use it to make new rope plate screws, and also made screws that work with my puller kit so I don’t have to hammer on the flywheel nut to get the flywheel off.
But here’s one for you. Check out the slotted hex-head bolts that are used to fasten the cylinder castings to the crankcase. They are 20 TPI but the major diameter measures at about 0.260″, whereas most 1/4″ fasteners measure a few thou under 0.250″. Using a regular 1/4-20 fastener is not recommended for that particular application.
Hope it helps, but it’s somebody else’s fault if it doesn’t
Best,
PM T2
He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...
