Atlas/Craftsman spindle shaft TPI size.

[LX Kid]

I have an Atlas/Craftsman 618 lathe, 1947 vintage, l am in need of a chuck with or without a mounting plate. I know my shaft is 1" but don't know the TPI. It has spindle bushings and "not" Timken bearings. Does anyone know for sure what the chuck spindle thread size is. (Some say 8 tpi and some say 10 tpi.) Thanks, Ron
Side Note: Anyone want to trade my 3-jaw outside holding chuck for a center holding 3-jaw chuck?

 

[Ulma Doctor]

1"-10TPI

 

[benmychree]

You should be able to measure the thread pitch with an ordinary steel rule if you do not have a thread pitch gage, which is one tool that you should own.

 

[LX Kid]

You should be able to measure the thread pitch with an ordinary steel rule if you do not have a thread pitch gage, which is one tool that you should own.

Looking at my center pic above, with the rule, it "appears" to me that spacing is every 1/8" which to me seems that it is an 8 tpi.

 

[MrWhoopee]

That certainly looks like 8 tpi to me. Regarding your chuck, you are missing the second set of jaws. Happens all the time when someone unfamiliar with the lathe sells it.