What thread?

[VolansParticipant @volans]

I am about to start to build my 1st stationary engine. Many years ago I worked for a company that restored traction engines, as well as industrial boiler services.(Eastern boilerworks, perhaps someone out there remembers them) – I only mention this so that you know I've a working knowledge of steam.

I have B.A. & metric (course) taps & dies. I notice that ME threads are used for fittings, is there any reason for that? Basically I can't decide whether to stick with what I've got, or buy a set of ME.

Also I read somewhere that ME threads can't be cut on an ML7, but my threading chart shows both 32 & 40 tpi???

[VolansParticipant @volans]

Making my 1st stationary engine.

[Jim NicParticipant @jimnic]

In my experience commercially available fittings use ME so if you want to make matching fittings on your model you will need the appropriate tools. I use mostly 1/4 x 40 and 3/8 x 32. The size of your model will to some extent dictate the size of pipework and fittings to look right. If you are content to use the commercial items throughout then you probably won't need to cut threads at all.

Of course if you want to make complete fittings for yourself you can use any thread you like.

Jim

[Anonymous]

The ME thread series are, of course, Whitworth form. They were introduced in the late 1940s to provide fine pitch threads for pipe fittings and the like. In the small scale models common at the time the existing BSW and BSF threads were much too coarse for scale fittings. I'd be amazed if a Myford couldn't cut 32 and 40 tpi. It's a doddle for an imperial lathe and shouldn't be too much bother on a metric lathe.

I use whatever threads are appropriate on my engines, mainly BSF, BSP, BA and ME, plus metric if I'm using commercial screws and bolts.

Andrew

[HOWARDTParticipant @howardt]

I use ME on bought steam kits, as that is what is specified and fittings are readily available. On my super simplex build I mainly use metric fine thread where I am making both mating parts, again where commercial fittings go use ME. Of course you could use all metric but commercial boiler may well be ME.

[IanTParticipant @iant]

Both my Myford S7 and EW have 8tpi leadscrews, so it is very simply to cut 32 & 40 tpi threads on them – just make sure you use the correct tool form. However, you will probably use ME taps/dies to do this work anyway – unless you need to 'start' the thread for some reason.

For my 'steam' models, I still use BA threads and have all the dies/taps required to do so, as well as a large stock of BA screws/nuts. However, the smaller BA sizes (14/16BA) are now getting very hard to find and where I need something that size or smaller (for my modelling) I've started to use the smaller metric threads.

I also use metric for all my 'new' build tools & fixtures but keep to imperial where the machine was originally built using older screw types. Then, if I go to my 'old' machines, I know what I need in terms of allen key/wrench tools etc e.g. don't mix threads n old machines!

Most (but not all) of my new Chinese stuff uses metric of course.

If I was 30-40 years younger, I would just go with metric but even so, I think ME might be very useful for some things…

Regards,

IanT

[Philip RoweParticipant @philiprowe13116]

Posted by Andrew Johnston on 21/12/2021 12:55:32:

The ME thread series are, of course, Whitworth form. They were introduced in the late 1940s

Andrew, are you sure about this? I have LBSC designed models, an 0 gauge "Sir Morris de Cowley" and a 2 1/2" gauge "Annie Bodie" built by my grandfather in the 20s and 30s and they both use 32 and 40 tpi threads. Phil

[IanTParticipant @iant]

Nearer 1912 I think..

IanT

[VolansParticipant @volans]

Wow! thanks for all the prompt replies.

[Speedy Builder5Participant @speedybuilder5]

Screwcutting BA threads will be a headache (on most lathes, ML 7s included) but most people use taps and dies as they much easier to use than having compound gear setups to achieve near approximations to the BA thread pitches.

[Anonymous]

Posted by Philip Rowe on 21/12/2021 14:10:41:

…..are you sure about this?

The information came from the WPS book on drills, taps and dies by Tubal Cain, in which he states that the ME thread series were standardised forty odd years ago. The book was published in 1987. I should have said standardised rather than introduced.

Andrew

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, you could get them in 1834 from G. Kennion & Co. who made taps & dies and claimed they could sell theirs cheaper by cutting out the middleman.

Regards Nick.

P.S. I've actually got a few narked "Ken" that were my father's and do still cut a decent thread.

Edited By Nicholas Farr on 21/12/2021 16:24:19

[SillyOldDufferModerator @sillyoldduffer]

Posted by Andrew Johnston on 21/12/2021 16:00:39:

Posted by Philip Rowe on 21/12/2021 14:10:41:

…..are you sure about this?

The information came from the WPS book on drills, taps and dies by Tubal Cain, in which he states that the ME thread series were standardised forty odd years ago. The book was published in 1987. …

In this thread, Nigel McBurney says 'According to Machinerys Screw thread book,1965 edition the model engineers thread was established in 1912 by a meeting of the SMEE and the editor of the Model Engineer'. I think that's right.

The confusion is likely because Andrew's reference is a reprint, not the first Edition. I guess naughty Tubal Cain wrote the original circa 1950, and should have given the year rather than ambivalently stating '40 years ago'.

Dave

[Michael GilliganParticipant @michaelgilligan61133]

Posted by SillyOldDuffer on 21/12/2021 16:24:41:

The confusion is likely because Andrew's reference is a reprint, not the first Edition. I guess naughty Tubal Cain wrote the original circa 1950, and should have given the year rather than ambivalently stating '40 years ago'.

Dave

.

An excellent hypothesis, Dave … BUT

According to Wikipedia [which, of course lacks Papal infallibility], not so

My guess is that the book is a collation of articles from Model Engineer … and it’s therefore the date of his writing the article for the magazine that defines the +40

MichaelG.

.

Ref. https://en.wikipedia.org/wiki/Tom_Walshaw

**LINK**

[Author]

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