Thread Size Help

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

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

David

Would This Table assist you at all?

Bill

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.

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

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

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.

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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.

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.

I always recommend the Motalia website for info on threads:

**LINK**

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

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

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

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.

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.......

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.

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

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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