Any one want enfield taps?

[Andyg009]

Ha s any one any idea where I can get Enfield tread taps and dies, particularly those for the treads used on the SMLE Mk III.

Regards

Andy G

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[Alan de Enfield]

Ha s any one any idea where I can get Enfield tread taps and dies, particularly those for the treads used on the SMLE Mk III.

Regards

Andy G

This has been asked on numerous occasions over the years and the general consensus is "not available".

The No1 threads were an in-house 'Enfield Special'

Examples :
Rear Trigger Guard Screw No1 Mk3 = 0.144" dia x 37 TPI
Front Trigger Guard Screw No1 Mk3 = 0.25" dia x 30 TPI

Rear Trigger Guard Screw No4 = 4BA (0.142" dia x 38.5 TPI)
Front Trigger Guard Screw No4 = 1/4" BSF x 26 TPI

Close but not the same

[Bruce_in_Oz]

Alan is spot on!

The only thing approaching a "standard" thread on a SMLE is the stock bolt: 0.4375 x 14 TPI. This is close enough to 7/16 Whitworth, apart from the "Enfield" thread form.

Enfield did its own "thing" with thread forms until the No4 came along. Lots of odd pitches: 33 and 37 TPI being popular. How many forumers have a lathe that will cut 37 TPI? Let alone the 26 1/3 TPI of the bayonet catch and nut and dial sight screw, or the 42 TPI on the extractor screw. With custom screw making machinery, it's a walk in the park, however, I suspect that the enormous problems of providing custom tooling to a myriad manufacturers in the peddled scheme of WW1 provided an interesting lesson. Hence the change to Whitworth, BSF and BA on the No4.

As near as I can understand it, Enfield thread form is 49deg 40min included angle, with radiused roots and crests similar to BA form. but I stand to be corrected.

Over on the Enfield Apprentices website there is a table of Enfield threads. See here:

Threads for Lee Enfield Rifle

Interestingly, this site lists the stock bolt as 7/16 Whitworth, but A. I. D. 1319 lists it as .4375 x 14 RH (Enfield Standard).

Hope everyone has had a good Christmas and best wishes for the new year.