What is this thread on hand presses?

[Mocivnik]

I've got myself a hand press(bottom pic, nr. 2), where all the dyes have this unusual(and unknown to me) thread on them, to fit inside (top). At first, I thought it's M6 (as it's very standard thread!) but by closer inspection, I noticed it's not. It's close, but it's not M6.

I measured the pitch of the thread and it's 24, while diameter (of screw) is 6.2mm. 
Does anyone knows what thread this is?

(I need to know what thread is so I can edit some other dies to it)

 

 

Edited March 21, 2019 by Mocivnik

[jimi]

It is possibly 1/4-24 then.

[Mocivnik]

Not just possible, 99% it is. As soon as I've finished this post I figured out that this is probably the right thread (but having a problem, since I don't find it by any standard..especially not on maryland metrics).

[Constabulary]

should be 6,35mm / 1/4"

Depending on the press you sometimes can buy adapters. I have a Shaeffer / Scovill press and it has a M10 screw-in adapter. So I can use M6 or 1/4" tools

EDIT:

this guy has several adapters - not sure if they fit your press but he had one for mine

https://tvt-web.de/Handpressen-und-Einsaetze/c1000253619_u8430_zfe1da35a-9517-44d6-bebf-8d5ed35e979a/

Edited March 21, 2019 by Constabulary

[jimi]

13 minutes ago, Mocivnik said:

Not just possible, 99% it is. As soon as I've finished this post I figured out that this is probably the right thread (but having a problem, since I don't find it by any standard..especially not on maryland metrics).

Could be this one but not 100% sure. it is UNS. Best way is to get hold of a thread guage.

https://www.ebay.com/itm/Lots-1pc-HSS-Machine-1-4-24-UNS-Plug-Tap-and-1pc-1-4-24-UNS-Die-Threading-Tool-/162544431108

Edited March 21, 2019 by jimi

[Mocivnik]

Haha :D  I had already opened this one in my bookmark :D

https://www.ebay.com/itm/1set-1-4-0-25-inch-American-Standard-thread-HSS-Machine-Plug-Tap-Die-Tool/113597039233?hash=item1a72e94281:m:m3VtHpyglUBMi6wmV1XySjg

8$ isn't so much for a tap + dye while i have to make 2 handles for dyes and cut ~10 taps on my tools, which aren't compatibile with press (yet).

 

I've measured it before. But I cannot measure the gauge on the inside, as it's too small hole. I can measure it on "screw" part because it's outside.

 

[JLSleather]

1/4" aes threads are generally 20 or 28 tpi.  

Maybe an M7x1? (24 pitch is .041")

 

Edited March 21, 2019 by JLSleather

[Mocivnik]

@JLSleather: You had me for 5 mins now.

I went to workshop downstairs and tested - it fits, but loose. Probably because the diameter of screw is 6.2mm instead of 7.0mm(as for M7).

I think that 1/4-24 is the right one.

And it's the same problem for M6 screw, which has pitch of 1mm (25.4 threads per inch). It fits first two turns, but then it gets stucked.

(And as we all knows, dies should sit NOT on thread.)

[fredk]

1/4 - 24 is a very old machinist's thread size. Used on Veteran/vintage [antique] cars, Steam Traction engines and industrial machines from the mid 19th century onwards. Its continued use is like 1/4 - 20 still being used on camera equipment and bicycles. I think, afair, my 1930 Austin 7 has some bolts of this fitting

[Constabulary]

Very uncommon for a button press I think - common standards are either M6 or 1/4" / 0.635" 

I would either return the press or the tools - or both. I switched on my press from M6 to 1/4" because it seems to me the 1/4" is more common / you get more tools.