Thread on No1 eject screw?

[RJW NZ]

Hi,
I've been searching but only find No4 info, does anyone happen to know what the thread/tap info is for the eject screw hole on a No1 1907 receiver is?, I'm guessing that its the same as the No1 Mk3, its 100% not the same as a No4, the screws don't interchange.
thanks rjwnz

Information

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[Rastis]

Try 0.1656 x 37 TPI.

From link below.

Threads for Lee Enfield Rifle

Rastis.

[RJW NZ]

Thanks for that,
I tried the local enginereing thread shop but they seem to have nothing close, it makes me wonder if anyone has ever found a similar thread that might work, I'm looking to tap a hole and use an original screw. thanks

[Rastis]

G'Day,
Unless you are lucky enough to jag a armourers tap, I think the only option would be to machine some silver steel to the correct thread, machine some flutes and harden it to make your own tap. The closest standard thread would be 8-36 UNF which would be close.

Rastis.

[RJW NZ]

Thanks!

[Peter Laidler]

RJ........ there's more questions than answers here........ I ask why is it necessary to drill and tap a hole in whatever it is, using some archaic non interchangeable or even standard thread. I appreciate that there's a good(?) reason but with my engineering hat on, I'm at a loss as to fathom why.

If it was me, looking for absolute originality for some project (like restoring my Norton many years ago and there must be thousands out there who have done the same on old Triumphs - bikes and cars - and MG's) and not wishing to use equally obscure BSF/BSW threads, I made the bolt HEADS look original but the threads were UNF. Couldn't you use the same trick with a No1 ejector screw...... same head but modern thread!

My friend Terry Mitchell, the former Engineering Director of MG did the same with an old wood-block pedal 'Hercules' push bike he restored. That way he could keep the original tool kit in the saddle bag but had 'proper' threads and HT steel bolts in the bike

Anyway, just my 2c's worth

[Patrick Chadwick]

A trade secret from Patrick's Khyber Pass Advanced Engineering Plant:

Don't make life unnecessarily complicated. Just get hold of* a 3 BA** steel screw, grease*** it well and work it in gradually. You do not want a hardened steel screw, as you want the thread on the screw to form itself to fit the rifle, not the other way around! If the screw ever wears so much as to be useless, just get another screw and do it again.

No tapping, no alteration to your rifle. Just work the screw back and forth until it can be screwed right in. But you must have a well-fitting screwdriver blade.

*If you don't know where to find such a thing, contact the Auckland model engineers club.
** OK, OK, 8-36 if you are really stuck.
*** I now actually use a special anti-sieze spray that is a fine oil loaded with aluminium powder. Works like a dream for such reforming operations. But the first time, I did this trick with grease. Just takes a minute or two longer.


Patrick


P.S: The trick works with a 3 BA because, although 3 BA has 34.8 tpi, the top diameter is 0.161" and the threads are sharper (47.5 degrees) than the Enfield. The thread length in the receiver is rather short, so the BA thread can be reformed sucessfully.

An 8-36 has a top diameter of 0.164" and an 60 degree angle, flatter than the Enfield thread so the 8-36 would be filling the space much more tightly than the BA, and could jam quite fiercely, depending on how precisely the thread was cut. So if you cannot get a 3 BA screw, then do as Peter suggested and put an 8-36 tap through the hole in the receiver. Strictly speaking, you have made an irreversible alteration to your musuem piece, but realistically - who will ever know, or care?

[RJW NZ]

good points all, will reply in 3 days, I'm out til then, wil think it over,

[RJW NZ]

Resolved:
What I was trying to do was go off the reservation again about keeping my enfields all original and install an old Ajak mount to my early shooter/project Enfield so I can use a scope and get some shooting done. I had found three antique screws from aperture sight set ups, each with the same thread as the eject screw, so it seemed a nice set up if I could find the proper tap for the other two holes.
In the end the 3BA HSS tap worked perfectly, as the differences in the threads only caused the screws to bind after the thickness of the receiver sidewall.

Now all I need is the other style Ajak mount with the two lock arms instead of the single, and I'll be able to fine tune a few other things, thanks for all the tips.

[Peter Laidler]

Phew..........!