Tel Sig MKIV ** 1915 - help?

[charadam]

I am in possession of a damaged example of the above.

The objective is rattling in its seating and there seems to be a 2.4mm thick component missing from the lens. By this I mean that, with the lens retainer fully home, there is a 2.4mm gap. The surviving front(?) lens element is chipped also.

I am in a position to make a new lens and I understand that the original might have been an achromatic doublet, probably cemented.

Can anyone tell me what the focal length should be?

I have read the admirable Peter Laidler's archive without achieving enlightenment on this topic.

Information

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[Peter Laidler]

You're right........ The OG lens assembly is a doublet and you're missing one part of it. You can a) either modify your OG lens housing/carrier to accept a complete but slightly smaller diameter Telescope Scout Regiment OG lens cell assembly and lenses. You can do this by machining it slightly to accept the Sct Regt OG lens cell which you can solder in place. Problem solved.

Or b), you can just go and have a new matched set of OG lenses made. Your lens maker should be able to work out which lens is missing and from the remaining lens, work out the curvatures using a lensmakers clock gauge and thensforth the f/l of the doublet. Dead easy. Dead easy that is if you have the skill to do it yourself or have deep pockets so that someoine else can do it for you - especially getting the lenses made. But if you do go down the new lenses route, have 5 sets made because as sure as god made little green apples, if YOU want a set, there are many others out there that will want a set too!

[Surpmil]

Contact a gent named Terry Vacani. He can probably help, and if he can't he knows who can.

[charadam]

Thank you gentlemen!

I have fired off an email to Mr Vacani.

Incidentally, Peter, were we acquainted in '68/69 at 40 Base?

[Peter Laidler]

er.......... I don't remember a Cfn Charadam........ remind me! I came down from 8 RAR with Dudley (Fitter Turners course) and Taggart (Armrs 1 course)

Surpmil, does this Mr Vacani deal in these big scopes? Should we all know about him?

Incidentally, the lens maker I use says that - off his head of course - that due to the long f/l and inbuilt focussing mech of the Scout Reg scope and the optically similar GP scope that it should be feasible to use optical/hard plastic to make both lenses or better still, the missing one. The sort of plastic used to make spectacle lenses

[charadam]

Peter,

My "real" name is Charlie Adams. I was an air tech and came down from Kluang with 75 Ac Wksp.

I believe we may have met as I was in and out of the armoury on shooting team activities.

All best.

[Peter Laidler]

It wasn't you that dropped the Scout into the sea looking at the Repulse and Prince of Wales wrecks was it...................?

[charadam]

No, but I was on the salvage party.

[Surpmil]

Peter, Terry Vacani has been very well-known in the binoculars and telescope collector worlds for quite a few decades as a dealer and repairer. He is one of the last of his generation still in that sort of business I would think, which is why I suspect he would have the best idea of what might be found where.

There is another option, which is to pick up on eBay or elsewhere, one of the many telescopes built from surplus parts or to military specs (more or less) and remove parts from that. I don't know enough about the details of the various models to say which would have the lenses the OP wanted.