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.

 

 

[Mocivnik]

@Constabulary: Well, actually..quite common here. Dies comes from Italy and I don't really know why they use this system. Company called MOVI, from this site http://www.fbg-italy.com/ .

The press was bought in Slovenia, but I believe it comes from Italy aswell, as I could find it in their catalogue. I don't mind very much about it, since I had bigger press and had to re-do taps on my dies (some time ago) so they were compatible as much as 1/4-24 as with M6 (the difference is really small, 1.4mm on 1 inch).

I will buy tap and dye and just make all of them on same size (1/4-24) and hope never to change any system (as it's going to be VERY expensive).

 

[Matt S]

I have one press with a 1/4-24 top thread and one with a M8 top thread. It is a pain to have to keep track of incompatible top tools. Luckily the bottom tools are interchangeable.

One day I'll get around to buying a kick-press and sell off my hand presses and all my incompatible dies.

[Mocivnik]

if I can help out here, buy a press like this. This is mine, I got used for 100€ or 86 GBP or 113$. I added the laser-cut measure guide with caliper-like scale (i draw it fast and just cut it out) so I can use different tools and just read out the number, how high has to be lifted the front part.

The piston has hole in middle of 12mm or 12.7mm ( I don't remember) and I just turned the adapter for M6 inner thread (for my dies). Adapter could be seen just the tip.

On the bottom, there is silver plate, which has hole of 12mm through, as all my dies have diameter of 11.9mm or 12.0mm. I planned to do just the "tip of the 24mm hole" for some other dies, but some things happened recently so I just abandoned further work in this workshop and moved to another.

The press work through eccentrical mechanism and more you press it (down) easier it gets, the force gets bigger (but the movement is getting smaller). It's a bit complicated to explain, but this works like a charm. I still own it (this is from my ex. workbench) but due to some difficulties I'm facing, I can't reach it.

(lifehack: sacrifice a wrench for a tool - like I did. I bought an extra one just for this press, driller 2 holes through it and attached 2 strong magnets. Everytime I need it, I know where I can find it. And I use it just for this press and nothing else. Both sides.)

Edited March 22, 2019 by Mocivnik