Thread Size Help

[Steve CrowParticipant @stevecrow46066]

I'm trying to find a thread (with available taps) with a major diameter of less than 2.4 mm and a minor of 2mm.

It's for a shaft that passes through a 3/32 bearing which needs a nut that clears a 2mm section.

And it would make life much easier if it was 60 degrees as well.

I'm not bothered about the die as I can single point cut it.

I've looked at the usual places. Zeus charts, Tracy Tools and Google but can't find anything.

There must be some fairly fine 3/32 thread out there.

Cheers, Steve

[Steve CrowParticipant @stevecrow46066]

[David George 1Participant @davidgeorge1]

8BA could be ok 0.086 " diamiter. (2.18mm)

David

[peak4Participant @peak4]

Would This Table assist you at all?

Bill

[Pete RimmerParticipant @peterimmer30576]

If you can single point that small cut a 3/32"-40tpi thread in silver steel, harden, grind 3 sides to make a tap then use the tap to make a nut. Cut the same thread in your part.

[JasonBModerator @jasonb]

3/32 x 40 would need a minor dia less than 2mm, even 3/32 x 48 Whit has a minor dia of 1.7mm.

Unlike the chart above this one shows both major and minor diameters but I can't see much that would suit. I'll have a look and see if a 60tpi spoke thread may fit the bill

[JasonBModerator @jasonb]

If the load is not great you could thread your rod M2.5 x 0.45, the crests would be a little flat but you would get a minor dia of 1.948, but as tapping size is generally 2.1mm that will slide over the 2mm section.

Most of my smaller upto 24mm bore engine have a lot of studs made from 3/32 rod, threaded M2.5 and holes drilled 2.1mm tapping size and none have fallen apart yet.

Edited By JasonB on 16/09/2019 07:16:35

[Clive FosterParticipant @clivefoster55965]

For this sort of thing you need the list of threads in pure size order regardless of type originally created by Andy Pugh.

Much easier than normal listings 'cos you don't have to identify the thread type first. Normal way is far better if you plan to cut threads tho'.

The essential "wot thread is it" identifier here :- **LINK** in text format which may need bit of massaging for easy reading.

A bit of web searching should find links to a pretty Excel file version, which I use. Google should find a direct download link.

A pdf version here :- **LINK**

There is also an HTML version here **LINK**.

Clive.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Clive Foster on 16/09/2019 12:29:44:

[ … ]

A pdf version here :- **LINK**

There is also an HTML version here **LINK**.

.

That PDF of the list that that Jason linked earlier is useful … Thanks, Clive

… but you appear to have [dare I say] 'screwed-up' the link

Hopefully this ammeded version works: **LINK**

https://fromtheframeup.com/uploads/TT_Thread_size_chart.pdf

MichaelG.

[BazyleParticipant @bazyle]

Why not just invent your own thread? If you are able to single point the thread you can make a tap for the nut too. If you end up with something standard but a bit obscure no body in the future will be able to identify it for spares anyway.

[old martParticipant @oldmart]

I always recommend the Motalia website for info on threads:

 

**LINK**

Edited By old mart on 16/09/2019 13:06:47

[JasonBModerator @jasonb]

I gave the M2.5 option earlier as Steve seems to work in metric but the other option is the good old model engineers favorite that can be found on many designs going back through teh years of 7BA on a 3/32" shaft which is much the same as using M2.5.

And just to show that the practical method can sometimes be better than the tables which may suggest that both will not fit over a 2mm shaft as minor dia is less than 2mm this photo shows a 2mm drill with 7BA nut to the left and M2.5 to the right (small hex) &BA from EKP, M2.5 from GHW so both good quality machined nuts not even looser mass produced items

[Steve CrowParticipant @stevecrow46066]

Thanks everybody, I had considered inventing my own thread (M2.3 x 0.25 sprang to mind) but I don't have access to a grinder so the thought of making a tap of that size is a little daunting. If I had a bit more time on my hands I would give it a go, especially as the nut will be brass.

Thanks Jason, I like the M2.5 x 0.4 idea as I already have taps and dies. I like to work in metric but I mix and match when it comes to very small stuff to get a wider range of sizes. Hence the use of a 3/32 bearing.

Also there are some great thread charts linked above. Very comprehensive yet Tracy Tools stock threads that don't seem to exist anywhere else!

Cheers

Steve

[JasonBModerator @jasonb]

Here is another good site, even has threads that Tracey don't, handy if you want to make things like milking machines and jam jar lids

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 16/09/2019 18:14:57:

Here is another good site, even has threads that Tracey don't, handy if you want to make things like milking machines and jam jar lids

.

Nice to see that they even got the 39mm Leica screw right [26tpi]

**LINK**

https://www.gewinde-normen.de/en/camera-mount.html

MichaelG.

[Steve CrowParticipant @stevecrow46066]

That's some site. The very first page I looked at, I saw the thread I want! It' s a 3/32 100tpi sewing machine thread!

I'm sure taps for that are easily available…….

[Neil WyattModerator @neilwyatt]

Posted by Steve Crow on 16/09/2019 18:02:05:

Thanks everybody, I had considered inventing my own thread (M2.3 x 0.25 sprang to mind) but I don't have access to a grinder so the thought of making a tap of that size is a little daunting. If I had a bit more time on my hands I would give it a go, especially as the nut will be brass.

Thanks Jason, I like the M2.5 x 0.4 idea as I already have taps and dies. I like to work in metric but I mix and match when it comes to very small stuff to get a wider range of sizes. Hence the use of a 3/32 bearing.

Also there are some great thread charts linked above. Very comprehensive yet Tracy Tools stock threads that don't seem to exist anywhere else!

Cheers

Steve

For brass you could try just screwcutting a bit of silver steel and filing three flats on it. For tougher materials, you could taper the silver steel and use a dremel with a cut off wheel to put some flutes in it.

Harden by heating quickly to bright red, dipping the tip in water. Then stick in a hot oven for half an hour to temper.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 16/09/2019 22:26:27:

.

For brass you could try just screwcutting a bit of silver steel and filing three flats on it. For tougher materials, you could taper the silver steel and use a dremel with a cut off wheel to put some flutes in it.

Harden by heating quickly to bright red, dipping the tip in water. Then stick in a hot oven for half an hour to temper.

.

… or even try some of that Blue Pivot Steel that you [Steve] are experimenting with.

[saves all that risky heating and quenching business]

MichaelG.

[Howard LewisParticipant @howardlewis46836]

I don't think for an instant that Ernst Leitz would mix Metric and Imperial.

I am old enough to remember that the Leica 39 x 1 predated the Edixa thread, later adopted by Pentax,and others, of 42 x 1, for S L Rs., before everyone changed to bayonet fit lenses and accessories.

The parts that i had made with a 39 x 1 thread worked perfectly on my cameras, which were Leica thread!

Howard

[peak4Participant @peak4]

Posted by Howard Lewis on 17/09/2019 19:41:36:

I don't think for an instant that Ernst Leitz would mix Metric and Imperial.

I am old enough to remember that the Leica 39 x 1 predated the Edixa thread, later adopted by Pentax,and others, of 42 x 1, for S L Rs., before everyone changed to bayonet fit lenses and accessories.

The parts that i had made with a 39 x 1 thread worked perfectly on my cameras, which were Leica thread!

Howard

Unlikely though it seems, I believe that 26TPI is correct.
Amongst other sources, the explanation is on Wikipedia HERE

Some other makes however did us a 39x1mm thread, e.g. Zenith, but I think they were a different flange to focal plane distance. Also on Wiki HERE

How this all works with the German inch, I'm not entirely sure, given that the said German inch was normally 1/12 of a foot, but could be 1/10, or 1/11; Oh and their foot used to be different to ours as well.

Holtzapfel on the other hand…………….

Bill

 

Edited By peak4 on 18/09/2019 00:12:01

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Howard Lewis on 17/09/2019 19:41:36:

I don't think for an instant that Ernst Leitz would mix Metric and Imperial.

I am old enough to remember that the Leica 39 x 1 predated the Edixa thread, later adopted by Pentax,and others, of 42 x 1, for S L Rs., before everyone changed to bayonet fit lenses and accessories.

The parts that i had made with a 39 x 1 thread worked perfectly on my cameras, which were Leica thread!

Howard

.

Sorry Howard … Whatever you "don't think for an instant" : it's true

MichaelG.

Edited By Michael Gilligan on 18/09/2019 07:38:07

[JasonBModerator @jasonb]

Metric diameters and imperial pitches are quite common, just look at some of the combinations found on things like bicycle bottom brackets and axles particularly Italian stuff.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Howard Lewis on 17/09/2019 19:41:36:

I don't think for an instant that Ernst Leitz would mix Metric and Imperial.

[ … ]

The parts that i had made with a 39 x 1 thread worked perfectly on my cameras, which were Leica thread!

.

Howard: I accept that this **LINK** is only 'a page on the web'

https://web2.ph.utexas.edu/~yue/misc/LeicaLTM.html

… but it is, I believe, a reasonably authoritative description of the history.

Unless your cameras were actual early Leicas; it is quite possible that your cameras had M42x1mm threads … but that wasn't the point being made about Jason's link.

MichaelG.

[Howard LewisParticipant @howardlewis46836]

Sorry folks!

You think that I have been misled for the last 65 years?

Certainly, I do not believe what Wikipedia says, or any other site that says 26 tpi

I have used too many Leica fitting cameras, lenses and acessories to be in any doubt. .

Unfortunately, I have given away my "bible" on the Leica system,or i could quote chapter and verse.

The Leica cameras, from the 1 to the 111G and the clones (Tower, Canon, Periflex, Fed, Zorki etc,) and the Zenith 35M SLR, all used the 39 x 1 thread.

Check the history of the Leica camera. It was developed, originally just to test 35mm cine film, and did not have an interchangeble lens. Relatively few were produced with Compur leaf type shutters. The focal plane shutter allowed the use of interchangeable lenses.

I have just checked a set of Extension Tubes made by BDB of Luton ( who made all sorts of lens accessories, filter mounts etc ) and the packaging says "Fitting all Cameras with 39 mm x 1 mm pitch thread. Leica, Periflex, Zenith etc" A set of Leica thread Bellows also check out as 1 mm pitch, I have not checked my Periflex Focusing Screen, but can forecast the result.

26 tpi 60 degree form does not match as exactly as the 1 mm.pitch gauge.

Lots of Enlarging lenses also used the 39 mm x 1 mm thread, since Leitz originally intended the Collapsible Elmar to be removed form the camera body and used on the Valoy enlarger  to make prints from the negatives.

(There was a school of thought that the same lens should be used to enlarge the negative as to take the original photograph, in the hope that the various aberrations would cancel out )

I rest my case.

42 mm x 1 mm (Edixa, Praktika, Pentax etc ) came about with the need to increase the register from 28 mm, and the dimensions of the body, to accomodate the hinged mirror of the SLR.

Howard

Edited By Howard Lewis on 18/09/2019 11:36:32

[Michael GilliganParticipant @michaelgilligan61133]

[Author]

Posts