Enfield threads

[Enfieldlock]

Enfield threads, hope this helps:

http://freespace.virgin.net/j.frankl...read-table.htm

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[breakeyp]

Is there a source for Enfield thread taps and dies? I can see the external thread being cut by a lathe but internal threads would be hopeless that way. I am particularlly interested in the right hand thread for the clearing rod. Thank you.

[Peter Laidler]

Great article Jim. But during the last days of the No1 rifle we had a chart published in EMER's and sanctioned at RSAF whereby some of the Enfield threads could be 'opened out' or 'eased' to a BA size and even 60 degree metric. I seem to recall that 4BA featured too. Have you got a list of these that you could pass on?

On the other hand, originality today might over-rule the old 'utility' criteria that we used to adhere to.

It was this 'thread' thing that made mention using No4 strikers and cocking piece combination in the SMLE No1.

[Edward Horton]

Tools and taps and dies, very good place for American shoppers with Enfield’s or a 53 MG

British Tools & Fasteners

[JB White]

On the other hand, originality today might over-rule the old 'utility' criteria that we used to adhere to.

Utility. That probably explains the oddball No1 firing pin I ran across once. It had the early style nub/lump but had also been cut for the later twin pronged FP tool. I needed to relieve a side of the FP tool to accomodate the nub before I could work things loose.

[Enfieldlock]

Great article Jim. But during the last days of the No1 rifle we had a chart published in EMER's and sanctioned at RSAF whereby some of the Enfield threads could be 'opened out' or 'eased' to a BA size and even 60 degree metric. I seem to recall that 4BA featured too. Have you got a list of these that you could pass on?

On the other hand, originality today might over-rule the old 'utility' criteria that we used to adhere to.

It was this 'thread' thing that made mention using No4 strikers and cocking piece combination in the SMLE No1.

Peter, we spoke on this. The info on supposed substitute screws lies in the Pattern Room archives, which are now buried in the Royal Armouries at leeds.

[Patrick Chadwick]

Since BA replacement recommendations are not much use outside the UK, I have "internationalized" my solutions. The following are "good enough" replacements, unless you are in the habit of dismantling your rifles to inspect the screw threads under a measuring microsope. A good source of odd-ball screw-cutting gear is model engineer suppliers. Otherwise you maybe up that well-known creek without a 0.126 x 37 tpi paddle.

Original Replacement
0.1875 x 33 tpi.....2 BA (0.185 x 31.4)
0.181 x x 26 1/3 tpi..... 3/16 x 26 (so-called "Brass" or "ME" thread" 0.1875 x 26 cut with a tight die, bolt may still need to be rubbed down a bit to fit)0.1656 dia x 37 tpi.....8-36 (0.164 x 36)
0.144 x 37 tpi.....very tough. 6-36 is very loose, but try it if you're desperate.0.126 x 42 tpi..... 5 BA (0.126x 43)
0.114 x 49 tpi..... 4-48 (0.112 x 48)
0.096 x 56 tpi.....3-56 (0.99 x 56), may need to be rubbed down a bit to fit
0.084 x 57 tpi..... 2-56 (0.086 x 56)

That covers quite a few positions. Some solutions are very good. In all cases, it is advisable to use a plain steel screw (NOT hardened) so that the screw will deform (if necessary) to fit the rifle, and not the other way about. Better to need a new screw than a new action body! In cases where the pitch does not quite match, smear the thread with copper-or aluminium loaded "anti-sieze" grease, and proceed as for "pecking" with a drill - in a bit, out, in a bit more, out again etc until the full depth is reached. The metal-loaded paste will help the screw to adapt to fit the rifle.

Patrick

[scout7]

I have been there, done that. Now I don't feel like such a Neanderthal.

[Enfieldlock]

Despite all the doom laden predictions, there still appears to be plenty of spares about, especially screws. However when the very last one disappears, the manfacture is not all that difficult. As a trial run, we had some rear trigger guard screws made some time back. First they are the most easily damaged screw on a SMLE and it offered the opportunity to get some longer ones made for use with PH5A sights, (they went well, almost none left).

We will make screws when necessary. Modern NC lathes eat that sort of job. The wierd pitch specs on Enfield screws hold no terrors nowdays.

However where there is a need for a matching nut, it may be a different matter, ie. the Rear Nosecap Screw and the nut that fits into the fore-end. We would offer a 2BA set as a replacement. It would not be economically viable to have a tap made to create the screw. Likewise, the screw and nut that holds the rear sight protector in place have same thread so 2BA would do it. A metric equivalent is 4.5mm, that is not a preferred choice but tooling is available.

The inner band screw has already been made in 2BA. The 1950s production of SMLE spares included barrels. The Inner Band was made in 2BA along with its matching screw. Likewise the boltheads produced by BSA at the same time use Rifle No4 screws for retaining the extractor, that is a 5BA thread. The screw retaining the spring to the rear sight mount is 4BA on these spare barrels.

It would be interesting if someone can come up with the Vocab Numbers for these oddball items. But as these manufactured items were probably never destined for UK use, they never appeared in the inventory.

[Mk VII]

You will not be able to buy the Enfield threadform taps or dies these days, unless it is milsurp ones.
In practice, BAs can often be persuaded to fit, if the length of thread engagement is not too great.