Threading

[randyc]

This may be something that everyone already does but just in case ...

When cutting threads in a lathe, rather than using a thread micrometer I sometimes just check the fit with a nut from the hardware store.  A couple of them are stored in the same place as the taps/dies of the same thread dimension/classification/pitch.

This is normally adequate for class 2A threads (most common type) when you feel just slight movement between the nut and the threaded part.  If a rare requirement for 3A threads, with tighter tolerances, arises, the thread dimensions should be checked with the thread mike.

   

P.S.  I HATE measuring (or trying to measure) thread pitch using thread wires.  You need four hands most of the time, despite all of the weird suggestions (modeling clay, masking tape, styrofoam, etc) from experts.

   

[the penguin]

Randy,

remember nothing holds like a good cross thread.......

[randyc]

(08-13-2017, 09:14 PM)the penguin Wrote: Randy,

remember nothing holds like a good cross thread.......

[TomG]

Those aren't nuts. They are poor man's thread gauges. :)

[randyc]

(08-14-2017, 04:45 PM)TomG Wrote: Those aren't nuts. They are poor man's thread gauges. :)

Tom, after reading your comment, I had a thought:  could sawing through one side of a nut, cleaning up the threads and squeezing the nut in a vise - by trial and error - make a poor man's "no-go" gauge  ?  (Similar to adjusting a split die to fine tune thread dimensions.)  

Hmmmm, the problem would be calibrating that nut "gauge"  without a male standard.  Oops.

[f350ca]

Make the male standard, measuring it with thread wires.

[TomG]

(08-14-2017, 07:47 PM)f350ca Wrote: Make the male standard, measuring it with thread wires.

That's what I do to cut a female thread to size. Even if I don't need the male part, it's pretty quick to do and guarantees a female thread that is the correct size.

Tom