Lithgow HT scope rings screw pitch

[tbonesmith]

Hi pardon my muddling of the description, but can someone tell me the type of thread used in the rings of the Lithgow HT sniper rifle. They are the last piece of a restoration, and when I know what they are I can make them... and be finished.
Thanks a lot

Information

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[Son]

Hi pardon my muddling of the description, but can someone tell me the type of thread used in the rings of the Lithgow HT sniper rifle. They are the last piece of a restoration, and when I know what they are I can make them... and be finished.
Thanks a lot

Since seeing your post I've looked through all my material and cannot come up with an answer. I'm afraid I won't be pulling mine out to measure them, but you could possibly measure your rings and compare with this info...

British Tools & Fasteners - BA Thread Profile

The screws in the scope itself are BA (British Association) thread form. It's likely the screws clamping the rings to the tube are also BA. If you can decide which size, buy a screw and try it gently. They are available- with a bit of searching.

[ireload2]

Hi pardon my muddling of the description, but can someone tell me the type of thread used in the rings of the Lithgow HT sniper rifle. They are the last piece of a restoration, and when I know what they are I can make them... and be finished.
Thanks a lot

The following does not answer your questions but it maybe be handy later.

There may be another similar screw on one of your Lee-Enfields or in a junk box that you can carefully try in the rings. If you find a match check it with a pitch gauge or use the chart to get close. Then use your matching screw as a pitch gauge to make new screws.


Lee-Enfield Threads

[Bruce_in_Oz]

Hi pardon my muddling of the description, but can someone tell me the type of thread used in the rings of the Lithgow HT sniper rifle. They are the last piece of a restoration, and when I know what they are I can make them... and be finished.
Thanks a lot

Here is what I have. Unfortunately, I only have information on the brackets and bits attached to the rifle. I have not yet acquired the drawings for the rings or scope. I suspect the clamping screws for the rings will be BA and not some "Enfield Special" for two reasons: the screws in the mounts/pads/brackets are BA and by the time of this project, odd threads in things like outer bands were being substituted with BA threads under specific conditions.

Anyway, regarding the bits attached to the rifle:

The mounting screws for the brackets are 4BA. There should be 5 of them: two in the front bracket and 3 on the rear.

Datum for the alignment of the brackets is the true centreline of the bore, NOT the receiver. The centre of the transverse pin in the front mount should be 0.735" above the CL. The top flat of the rear bracket should be 1.086" above CL. There should be a distance of 4.344" between the centre of the front transverse pin and the centre of the hole for the "Bolt, locking" (locking lever).

See: ADD(S) 21-100, Rifle No1 Mklll, Sight Telescopic, Attachment - Assembly.

This document also notes: Brackets to be sweated to Body on assembly.

The references for the telescope fittings are: 1. ADD(A)57-137 and 2. ADD(A)57-123 for rings attached to telescope. Does anyone have a copy of those and want a copy of ADD(S) 21-100???

[tbonesmith]

Have checked with bases screws and the rings are a smaller thread, don't have finer BA threads to test with.

[newbieDAN]

shameless Bump

---------- Post added at 12:32 AM ---------- Previous post was at 12:28 AM ----------

How do I find these ADD(A) design division, Department of the Army drawings?

[Bruce_in_Oz]

DAN,

Sadly, much of this information, especially the actual drawings have either been destroyed or locked away in dark places, away from "enthusiasts" like us.

About a decade ago, I was fortunate to get my sticky paws on a lot of reference data about drawing numbers and such, but actual drawings to hand are very few. I have some SMLE component drawings and general layout stuff. Another part of the problem is that for any given drawing, there was a manufacturing "process book" and a set of detailed instructions for heat-treatment and surface finishing.

Stuff is made differently these days, so a lot of the old process stuff is redundant.

[muffett.2008]

A good supplier of BA threads is your local hobby shop.