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I get grease zerks in all sorts of different threads; 6mm x 1mm tapered [only time I've seen a tapered metric thread] is most common on this side, I buy them by the dozen.
npt 1/4", 1/8" too.
But never seen 1/4- 28.
I've often wondered about those schrader valve threads, so thanks for another bit of useless trivia no one I ever meet will ever care about!
I've learned to just keep quiet about my thoughts...
1/4"-28 is very popular in automotive parts, over here anyway.
The Schrader thread sizes became very important, when buggered up valve core threads became the difference between a million dollar piece of equipment running.....or not.
Sometimes, you never know what you might need to know, and have!
Russ Hanscom wrote: ↑Sun Jul 26, 2020 12:37 pm
Has anyone run across a 19/64"-32 die? (aka .2969"-32) .................................................. Plan A is to see if a 5/16-32 in a Geometric head will collapse enough. ..................................................................
Not a problem , I do that all the time with my Geometric head
You can go about .062 Plus or Minus from the Die set size.
So a 5/16 die should work fine
Rich
As a side note. write down where you have those indexing marks and keep it with the Geo head
so next time you don't need to hunt for the right setting
Rich
A note to those not familiar with Geometric heads.
These Die heads were greatly used by Screw Machines years ago, but when CNC lathes and machines took over,
They became obsolete. They have Die inserts ( threaded cut edges) that can be resharpened and in order to allow that, the heads
are adjustable for thread size as a resharpened edge would cut an oversize thread without this adjustment.
This can be of great use when you do not have all the different size dies, so you can use the thread count
So your 1/4-28 die can also cut a 5/16-28 thread or a 12-28 for example