The Home Machinist!

These guys are great to deal with and very well versed in sleeves for various manufacturers etc. Got an adapter for my Boxford L00 to 5c and they had the Boxford specs on hand. They deal in more than their site lists.
https://www.jfkprecisionproducts.com/

A bit more money, but Kevlar hoses are game changing if you braze with any regularity. I will never go back to standard hoses if I can help it.

L tapers work excellent and have large pass through. Wrenches are easy to make or buy... and yes you need a wrench.. not good for spindle nose, chuck, or work to run loose.

Generally, when a saw gets finicky out of the blue, it's time for a new blade. -ST-

I drilled the carriage on my Boxford and pressed in four oiler dimples. When I pump Vactra into them, the carriage will actually lift if not tightened down. Chips etc are flushed out and away from the wipers, and I figure I get oil exactly where it needs to be. -ST-

Keep top speed in mind. Many of the very nice older American lathes mentioned earlier have very low top speeds. Let your intended use be your guide... or better yet buy a bunch of lathes! -ST-

Hot rolled steel and steel that has been worked hardened will also move quite a lot when the 'skin' is cut off a side.

Calipers are not that accurate. Beg, borrow, steal a micrometer for what you are doing. -ST-

Hell yes. -ST-

Surprised nobody has asked as to what you are threading with. Good tool, decent metal, higher speed if necessary. -ST-