need help identifying these thread dies

[BTL-A4]

I have a "Card's Improved Screw Plate" tap wrench set with 3 dies: 1/4"-20 and 2 other ones that appear to be marked 14-20 and 16-20. An AI-assisted search determined that the 14-20 was for a #14 screw, now obsolete, and would make a very tight-fitting 1/4-20. It also determined that the 16-20 was the same as a 3/8"-20, as #16 is also obsolete. Can someone verify this for me and/or tell me what these dies are used for? Thanks!

Photos:

 

[LopezBart]

This post from Practical Machinist discusses these obsolete sizes; my references go back to the late 50s but these sizes appear older than that....

https://www.practicalmachinist.com/forum/threads/us-machine-screw-threads.355403/

Here's a copy of screw sizes from https://www.aomci.org/forums/topic/old-and-unusual-screw-sizes/:



You can also find a mashup of all sorts of thread data here: https://pages.cs.wisc.edu/~bolo/workshop/thread.html

 

[BTL-A4]

Thanks! Seems the ones I have could be watchmaker or jeweler tools.

 

[Beerhippie]

my references go back to the late 50s but these sizes appear older than that....

Odd. I recall buying and using #14 machine screws and I only date back to the '60s.

 

[PCustoms]

Thanks! Seems the ones I have could be watchmaker or jeweler tools.

That's a big *** watch

 

[RTM]

1/4"-20 and 2 other ones that appear to be marked 14-20 and 16-20.

Yup, those all look like realistic sizes, as AI noted. I have a 14-20 and 14-24. One of my thread plates has a 20- something, need to research that again.

While those sizes may be obsolete, so are many of my WW tools, so I keep them around for repairs. Loan them to friends who also own obsolete stuff

 

[whateg01]

#14 hung around as a wood screw size for awhile, as I recall. I still have 14-20 tap that I bought at Ace hardware probably about 20 years ago, thinking it was 1/4-20. Baffled me why I couldn't get 1/4-20 screws to go in. I should still have it somewhere since I don't get rid of anything. No idea what I would use it for now.

 

[turbowoodworker]

Question, do you know that the thread pitch is exactly 20 tpi? The third die is labeled like a typical 1/4- 20.

 

[turbowoodworker]

Second question, the third has the label U.S.S Card. Might this be a remnant of the ship’s maintainance dept.?

USS Card - Wikipedia

en.wikipedia.org

 

[RTM]

the third has the label U.S.S Card. Might this be a remnant of the ship’s maintainance dept.

Probably these people

S. W. Card Mfg. Co. : Catalog No. 34 : S. W. Card Manufacturing Co. : Free Download, Borrow, and Streaming : Internet Archive

168 p., illus., 18.9 cm, trade catalog

archive.org

USS was a thread standard way back when, and they made the die.

 

[RTM]

Question, do you know that the thread pitch is exactly 20 tpi? The third die is labeled like a typical 1/4- 20.

I think he knew that.

Card's Improved Screw Plate" tap wrench set with 3 dies: 1/4"-20

 

[turbowoodworker]

Thanks. Being a Navy guy myself, my research took me in the wrong direction.
But, if interested, the USS Card had a very interesting history having been sunk by sabotage in Saigon harbor

 

[Beerhippie]

#14 hung around as a wood screw size for awhile, as I recall.

#14 wood screw is still around at my local hardware store. Completely different animal.

 

[The Cobbler]

off the web; A #14-20 screw is a heavy-duty imperial fastener with a diameter of 0.242 inches and 20 coarse threads per inch. It is almost identical in size to a 1/4-20

 

[PCustoms]

off the web; A #14-20 screw is a heavy-duty imperial fastener with a diameter of 0.242 inches and 20 coarse threads per inch. It is almost identical in size to a 1/4-20

Did you see post #2?