• Phoenix Rising from the Ashes - Part 2 (by Peter Laidler)

    The following article is published with the kind permission of Advisory Panel Member, Peter Laidler. Capt. Peter Laidler is the senior Armourer in the UK Military, now retired, but based as a Technical Officer at the UK Military Small Arms School. On behalf of MILSURPS.COM members, we'd like to publicly thank him for his support of this forum, as well the broader Lee Enfield collector community in general.

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    "Phoenix Rising from the Ashes"
    (Part 2 - The lenses and lens cells)

    or … how to rebuild of a totally unserviceable scrap No.32 telescope.

    By Peter Laidler

    We ended Part 1 (click here) of this series of articles regarding the No32 telescope with a complete, fully refurbished, concentric, almost as-new No32 Mk2 telescope tube. Some of you noticed the deliberate mistake that I threw in, just to see whether you were all fully awake. Yes, I meant 8BA erector cell locking segment cover screws and not 4BA!

    Now we’ll have a look at two important parts of the whole thing. The ocular or eye lens assembly and the erector assembly. I’ll start with the erector cell. Even if it looks perfectly clean, inside and out, you ought to strip it fully to do the job again, to YOUR satisfaction.

    First, a word of explanation. In the text I refer to a ‘counter cell’. This is what you might call a ‘locking ring’ or a ‘retaining ring’ or an ‘externally threaded ring’ or the ‘lens retaining ring’. All are correct.

    And secondly, screwdrivers……… All duly qualified Armourers and Instrument technicians that have these scopes in their charge have a set of suitable screwdrivers, made during their apprenticeships, for unscrewing the counter cells. I have to confess that mine are nothing too elaborate and they’re made from the tough steel of a mechanical hacksaw blade and ground to the exact dimension of the recesses of the erector and ocular counter cell slots.

    The Erector Assembly
    Exactly the same as the ocular lenses only this time, the erector focuses the graticle and inverts both the grat and image to present you with your x3 image. This time, it’s the shallow large diameter convex radius curvature that goes into the cell first, followed by the spacer followed by the next lens, small diameter curvature followed by the counter cell that seats onto the FLAT surface of the outermost erector lens. But that’s not all….. Some lens sets were ground with BOTH outer surfaces slightly convex. If this is the case with yours, then it’s the shallowest convex that faces the OG or graticle, thus Shallow curvature, deep curvature, spacer, deep curvature, flat or shallowest curvature, counter cell.

    (Click PIC to Enlarge)

    To strip the erector cell, then just do this. Remove the 10BA counter cell securing screw and with the aid of the correct screwdriver, that I’ve described above, unscrew the counter cell. It’ll take about 30 or so revolutions to unscrew it fully…………. Now gently tap the open end of the erector cell onto a table, covered with a clean table cloth or sheet. The first lens should emerge, followed by a spacer, followed by another lens. If the second lens doesn’t follow, then push it out, a little at a time, edge to edge and so on, from the rear, using a plastic lolly stick through the stop-down shroud hole, on to the edges of the glass lens until it’s clear. On most erector cells, the thin stop-down shroud is soldered and fixed into place while on the later versions, the stop-down shroud is screwed in like a recessed top and secured with a very small 10BA countersunk screw.

    If your stop-down shroud is battered and dented where a previous butcher has got at it, then radius it out using a suitably shaped bit of wood from the inside. And while you’re at it, paint the shroud part, inside and out with some matt black paint CLEANING. Thoroughly clean out the inside of the erector cell tube. Now get some methylated spirit on a piece of new, clean, white kitchen tissue and clean the surfaces of the lenses. Once they’re done, wrap them in some more clean tissue and put them away safely. Do the same with the spacer. Cleanliness is vital for these lenses. Please don’t use your grandmas old night dress or your wife’s dusters from under the kitchen sink. Only use NEW, fresh, kitchen paper towel

    It is while the erector cell is stripped that any of the adjustments I detail elsewhere must be completed. Assembly is a direct reversal of the stripping procedure BUT……… You will have noticed that the two lenses are very slightly different.

    1. The inner lens, the LENS NEAREST TO THE STOP-DOWN SHROUD, the first one to go back in and facing towards the eye is convex (an outward facing curve) on BOTH surfaces. There is a deep convex curve and a shallow convex curve. This is a DOUBLE CONVEX lens.

    2. The outer lens, the LENS NEAREST TO THE OPENING, the last one to go back, closest to the graticle, has a deep convex curvature side and a FLAT side. This is a PLANO CONVEX lens.

    The later Mk2, 3 and L1A1 ocular lens cell. These lenses are secured safely within a brass housing which screws into the tube. Assembly into the housing is exactly the same as the Mk1 types we described above. BUT, if yours are convex on BOTH surfaces, as some are, then it’s the smallest diameter curvatures (the sharpest radii don’t forget) that meet, separated by the spacer. Thus: Flat or shallow curvature, deep curvature, spacer, deep curvature, flat or shallow curvature, counter cell

    (Click PIC to Enlarge)

    To assemble the lenses, hold them in a piece of clean white kitchen roll and insert lens 1 into the erector cell, SHALLOW CONVEX side first, and if necessary, push it home using a CLEAN cotton wool bud. Now insert the spacer. Now insert lens 2 DEEP CONVEX side first. Put another way, you now have the shallow convex curvature facing the stop-down shroud, the two deep convex curvatures facing each other (the PLOSSL effect), separated by the spacer with the FLAT surface against the counter cell or locking ring.

    But it’s not quite that simple. If your erector lenses are BOTH double convex ….., as some late Mk3’s are, then the outer one must be the one with the shallowest convex. And this shallow convex must face outwards. Like this:
    Shallow curvature first, deep curvature, spacer, deep curvature, flat or shallowest curvature, counter cell.

    Now screw up the counter cell and insert the 10BA locking screw. It’s not important to lock up with the 10BA screw as the counter cell is not liable to unscrew! If you are not using the clean lens assembly straight away, then seal it in a little zip-lock plastic bag. Be warned. Dirt on these lenses is the arch enemy of the telescope. There, that’s one of the difficult jobs. The rest is pretty mundane……….

    Ocular end of the erector cell. This is the important shroud or stop down. This must not be damaged and must be central. The stop down shield or shroud should be painted matt black to prevent any light scatter.

    (Click PIC to Enlarge)


    Next, the Ocular or eye lenses or eye lens cell. The principle is the same. If you are refurbishing an eye lens cell, then look VERY carefully around the outer threaded edge of the cell before you go any further because hidden in among the thread or under a bit of grease there MIGHT lurk a hidden 10 BA locking grub- screw that’s ready to trip you up. If you do have one, unscrew it and discard it. Now you can remove the counter cell or eye lens retaining ring and hook out any spacers that separate it from the lens. But this is easier said than done I’m afraid because some of these telescopes and lens assemblies, usually late Mk3’s, were made to STAY assembled! So, I’ll keep it simple. Press out from the front, the inner lens, the sprung spacer and the outer lens and clean both using fresh methylated spirit and clean kitchen roll as you did before. These lenses are both identical and while there are two different types, they should remain as matched pairs.

    TYPE 1. Deep convex curvature internal surface with flat external surface on both lenses
    All Mk1’s, most Mk2’s and 3’s but later Mk3’s and some L1A1’s

    TYPE 2. Deep convex curvature internal surface with shallow curvature external surface on both lenses.
    These can be found in any of the lens cells

    I would advise you to note carefully the exact position of any other spacers that should come out of the housing and write it down! But GENERALLY, with a late Mk2 and 3 lens cell assembly, there is a .10” thick spacer, a lens, a wider sprung spacer, another lens followed by another .10” spacer then the locking ring/counter cell. If there is only 1x .10” spacer, then this is usually found under the locking ring.

    If you are fitting a lens cell or counter cell to a newly repaired tube, NOW is the time to make sure that the cell or eye lens retaining ring fits into the tube. Occasionally you will encounter tight threads. These simply need to be ‘chased up’ with a needle file or a suitably shaped hand held tool. If you need to do this on a lathe, I use an old electric jigsaw blade, ground down to a 55degree whitworth thread angle, just to chase the threads by hand on a slow running lathe. It always works against the brass cell housing. Another stumbling block is that SOME brass housings have the external thread machined down beyond the thread line of the tube you’re attempting to use. This means that while you can get the cell threads to mate and turn perfectly freely inside the tube, the threads bottom out before the cell is fully home. If you are mixing and matching lenses/lens cells/counter cells from a donor tube, now is the time to sort these little problems out. It is also possible/likely in the same mix and match scenario that while you get the Mk1 counter cell to thread properly into the ‘new’ tube, it might be too short to seat up against the outer lens, causing it to shake slightly. It MUST nip-up the lens. If it’s too short then do not be tempted to shorten the tube! It’ll only be short by up to .025” or so, so make a spacer with a loop of brass or copper wire and solder the two ends together. If the counter cell is too long, by the same amount or so, just machine a little at a time off the face. Simple isn’t it.

    The Mk1 and early Mk2 separate lenses. These lenses are retained directly into the telescope tube. Make sure that the edges are perfectly cleaned with methylated spirit and if there are any chips around the edges, touch them in with matt black paint. Before you insert them, clean the surfaces with clean methylated spirit and kitchen towel. Then insert, flat side in first, - sprung spacer, - followed by the second lens convex side first then the threaded counter cell. REMEMBER both convex surfaces must face each other. Thus: Flat, deep curvature, spacer, deep curvature, flat, counter cell.

    (Click PIC to Enlarge)

    You’ll understand from this, I am explaining detail that would never occur at an Army Field or Base workshop, simply because we’d have a huge box or tray of parts to get the best selective fit. And of course, we wouldn’t graft telescopes together unless there was a dire need. But, as usual, I digress………………………

    Only once these small problems have been solved, is it time to assemble up the lens cell assembly. Do it in exactly the reverse order you stripped YOURS. If in doubt, then this is a GOOD guide.

    Thin spacer, lens – FLAT (or shallow convex) to face OUTWARDS. Sprung spacer, next lens with FLAT (or shallow convex) to face outwards. That is to say on all occasions, the two DEEP convex surfaces should face each other, separated by the sprung spacer. Follow this by the second thin spacer followed by the locking ring.

    The same situation arises with the plain Mk1’s and 2’s where the lenses sit directly into the tube.

    Remember, do not touch the lens surfaces with anything except the kitchen roll. You MIGHT be tempted to put the well used and slightly scratched surface of the ocular lens into the inside of the telescope, keeping the bright and unscratched lens on the outside. Don’t! The reason is that the eye looks THROUGH the rear lens and on and on and on towards an image and into optical theory that is beyond this paper. So a scratched lens that is inside the telescope is obvious to the eye. As I said earlier, the eye scans INTO the telescope and will not focus/see/ignore a scratch on the outer surface, because it’s concentrating elsewhere. This isn’t strictly correct but for simplicity, sufficient for this paper.

    Once again, having been sure that these lenses/lens cell will fit into our telescope tube, wrap it/them up in a clean roll and zip-lock bag…………… You must take care that no grease or oil, even from your fingers and especially not lubricating oil is present on the lenses because it will attack them

    If you have restored your tube as I explained in the last article, you might find that there are traces of solder or even a small but almost invisible eccentric internal step inside the main tube.

    Mk1 or Mk2 tube, then this is of no concern to us at all because while you might not be able to push the erector cell into the tube from the ocular end, it’ll still slide in from the OG (or objective glass) end. But if it doesn’t, then mount the erector cell body in the lathe chuck and gently file off a thou - .001” at a time until it is a what we’d call in Army technical circles ‘a stonking good fit’. Remember that the erector cell will eventually have to be eased back and forth, through the segment cover, in order to focus the graticule post. If it’s a sloppy fit then the locking segment won’t hold it secure during recoil. That’s why we recoil test every rebuilt sight on a slave L42, with the recoil setting set to harsh. If it’s too tight, then you’ll have problems easing it back and forth. You might like to smear a dollop of graphite into the grooved locking splines of the outer casing.

    Mk3/L1A1 tube, the erector must be inserted from the ocular end due to the design of the diaphragm system. So carefully clean away all superfluous solder at the join to make any obstruction as invisible as possible before you skim the erector cell to fit from the ocular end.

    If your erector cell is a loose fit, you can cure it by means of a bit of a bodge……., but it’s an acceptable bodge in my opinion and this is what I was taught to do in the past. You need to press the locking segment down a tad harder onto the locating splines of the erector cell. To do this, use a suitable thickness of brass or steel or alloy shim cut to the exact size of the segment, hold it in place with a dab of graphite grease just before you need to secure the cover. You might find that a Coke can thickness is JUST what you need! This has in effect brought the segment locking splines down into greater contact with the splines on the erector cell. But DON’T overdo it. If your particular erector cell is a little looser that you’d like but stays rock solid during recoil, then that’s good enough.

    Now we should have a fully refurbished erector cell, with clean lenses that is a perfect sliding fit into the telescope tube. We’ve also got a set of perfectly clean ocular lenses, fitted into a brass lens cell that is a perfect screw-in fit into the ocular end of the tube too. If not the latter, then certainly two separate lenses and a counter cell/retaining ring that is an equally good screw-in fit too! All wrapped in kitchen roll inside zip-lock plastic bags

    While we’re here, we might as well got cracking onto the front lens….., what we call ‘the OG or Object Glass’. If you have a Mk 3 or L1A1 telescope, you MIGHT find that this lens can be removed from the housing via another counter cell in the rear. Just go carefully…. If you have a Mk1 or 2, then it’s not removeable but part of a roll-sealed assembly. To clean this, dunk it in some warm – NOT hot - soapy water and use a toothbrush dibbed into some soap, to simply scrub the back and front of the lens. Don’t overdo the scrubbing….. Shake out and leave to dry. Now clean with methylated spirit, wrap up in kitchen roll, and into a zip-lock bag.

    In Part 3 of this series of articles, we’ll have a look at the Mk1 and 2 range and deflection drums…………………

    Copyright ©2006 - 2009 by Peter Laidler and MILSURPS.COM

    Collector's Comments and Feedback:

    1. Capt. Peter Laidler is the senior Armourer in the UK Military, now retired, but based as a Technical Officer at the UK Military Small Arms School. In addition to being a trained and highly experienced military "Armourer", he has authored two excellent books about the No.4(T) sniper rifles and their No.32 scopes. They are titled "An Armourer's Perspective: .303 No.4(T) Sniper Rifle", which he co-authored with Ian Skennerton and his own dedicated work, "Telescope Sighting No.32".

    If you're really interested in some in-depth learning about the No.4(T) sniper rifles and the No.32 series of scopes, their history, evolution, repair and adjustments for shooting, I'd highly recommend those two books, which are pictured below.
    ....... (Feedback by "Badger")

    (Click PIC to Enlarge)

    Note: The opinions expressed herein or statements made in this article are solely those of the author, and do not necessarily reflect the views of the Military Surplus Collectors Forums, or the ownership and moderation group of this site. MILSURPS.COM accepts no legal liability or responsibility for any claims made or opinions expressed herein. Also, please note that neither the author nor MILSURPS.COM recommends that any member of these forums, or a reader of this article, try this type of experimentation without the proper knowledge, equipment and training.
    This article was originally published in forum thread: "Phoenix Rising from the Ashes" - Part 2 (by Peter Laidler) started by Badger View original post