80 threads per inch fastener close-up - photo

[Jon]

80 threads per inch fastener close-up.

Fullsize image: https://s3-us-west-1.amazonaws.com/h...r_fullsize.jpg




Previously:

NASA fastener design manual
Thread rolling machine - GIF
Bolt threading GIF

[TrickieDickie]

Now thats some fine threading

[McDesign]

That's not any thread profile I've ever seen - it doesn't really even look like a thread.

[DIYSwede]

1/4"-80 is not uncommon as micro adjusters in lab gear for optics and/ or high vacuum conditions.

Tutorial for the curious: Fine Adjustment Screws

[TrickieDickie]

My lathe will cut 112 per inch never had a need to but I am going to point up a bit and give it a try.

[DIYSwede]

-Good luck!
AFAIK, a single-point 112 TPI threading tool would need a 1,29 thou (32,7 microns) tip radius and a 5,48 thou (0,139 mm) DOC,
but merely choosing the right tool alloy to make that tip strong enough for 303 SS is beyond my knowledge horizon.
Then, DIY-ing a tool grinder for that geometry and checking its precision would be quite an undertaking...
Then making a durable tap is a whole different job.

[TrickieDickie]

I hear ya it would have to be a fine point to cut the 0.009 pitch.