Imperial threads on a Metric lathe.

[Frank S]

Thanks for the kind words, Ray.

Tell your students that the programs demonstrate why they should learn math. They show the type of real world problems that can be solved with math - especially so in the machine shop.

Not just for students Marv, your programs are a great help to some of us older farts who have lost a lot of our math skills due to too many years of not using them frequently enough.

[editor@glue-it.com]

I have to say, I really like the hand-cranked lathe, great for cutting threads up to a shoulder and when something is very delicate.

[DIYSwede]

I have to say, I really like the hand-cranked lathe, great for cutting threads up to a shoulder and when something is very delicate.

These days I mostly start from the shoulder, with an inside threading tool upside down in the tool post and run the lathe & lead screw in reverse: "The Lo-Anx way of turning to a shoulder".
The hand crank is still useful for toolpost grinding or milling threads with the TPMDGM:
DIYSwede's TPMDGM: A Flip-Flop ToolPostMiniDriil/Mill/Grinder for a 7x14" lathe

Cheers
Johan

[mklotz]

I have to say, I really like the hand-cranked lathe, great for cutting threads up to a shoulder and when something is very delicate.

The hand crank has another important use...

If your lathe uses screw-on chucks and you don't lubricate the threads before each mounting, it may be difficult to unthread later. (This is especially true if you don't change chucks frequently.) The temptation is to engage the back gears without removing the coupling pin, thus locking the rotation of the spindle. Then, when torque is applied to the chuck, often with a wrench, the back gears take all the force and you risk breaking a tooth or two.

A better procedure is to block the rotation of the chuck with a wooden block and use the crank to unscrew the spindle from the now fixed chuck.

There are numerous ways to build a crank; here's how I built mine...

Lathe hand crank