"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Existential Angst" fired this volley in
:

I figger that's gotta be the explanation?
I know about form tapping, just never heard of form-threading, which I
assume must exist.


Assuming the threads were cut, they'd have to begin with a blank that had
the thread area larger than the rest.

But that's not the standard way "screw machine" equipment works on cheap
fasteners. Not only does roll forming exist, it is the standard way by
which its done in mass-production.

They don't even use a "forming die", they use flat forming plates between
two of which the stock is rolled under extreme pressure to create the
threads.

Mystery solved!
Heh, but boy, the threads sure do *look* like cut threads!

So much for traditional machining, eh?
--
EA


LLoyd