Focomat Restoration

Way back in 2006 Leica followers received a bonus in that two subscriptions to the British Clubs were , in future, to be reduced to one payment!  This was brought about by the amalgamation of LPP ( Leica Postal Portfolios) and Leica Historical Society. Given that much duplication of membership existed this was, after some discussion, agreed and for a time the excellent format of the Historical Magazine was continued under Jem Kime as Editor. Today this magazine has been expanded for the combined Society. 

I was re (re-) reading some of these magazines recently when I came across an article by Jem regarding rewiring of Leica enlargers. This is a subject that has cropped up recently as such machines as the Focomat Ic grow older and while static wire is often acceptable it will be the old flexible wire that will surely be past its 'sell by' date.

It is not my intention to reproduce the work of Jem but if you can read his article it contains much on restoration and the conversion to IEC fittings of those odd baseboard sockets.

The Focomat Ic is the enlarger which often needs rewiring and, given that it was produced for 1950- 1978, there can be no reflection on the quality of original manufacture. One oddity to us in UK is however the use of German standard plugs and wire colours. 

Given the risks associated with mains electricity I can only warn that undertaking any renewal should be done by suitably qualified persons and so, and if any doubt exists, please consult a qualified professional.

The purpose of this Blog is to draw the attention of restorers to the availability of what seems to be replacement three pin German plugs such as used on the top of Focomat 1c columns in the post war period. I had thought that these were long obsolete before I discovered several on Ebay as new items in various colours and designs. Users will know that these plugs have 'half-moon' profile contacts and offer an earth pin.

A typical search is        

'Busch-Jaeger Terko-Stecker Sw 34 Wj'

but several are illustrated from various sellers, not all of whom will mail to the UK. I must add that I have not bought one of these but comparison with some of the data given by Jem Kime in 2008 suggests we are on to the right thing.

One vital last note is to record that German electrical flex colours differ from UK standards in  every way in the period we refer to. Details of the conversion of colours in wiring is best left to the professional guides  available. Suffice it to say that one should NEVER assume that a German wire colour is directly convertible to UK standard, old or new.

 

A new 'thread'....

Yes, this brief post refers to the Leica thread which has come to be known as 39 mm or LTM (for Leica Thread Mount). Not that one is likely to be able buy a brand new taking lens with this type of mount as they are now mostly found in smaller enlarging lenses, a (very) few reissues of classic lenses and the Cosina ranges.

There is a vast stock of taking lenses in this fitting which can, mostly, be adapted to Leica M mount or in some cases digital cameras  even, if in some cases, only for close up use. This field is truly is vast going back almost 100 years to say nothing of the large Russian/Ukraine/USSR ranges.

I recently had need of a 105 mm enlarging lens and had a late TTH (Taylor, Taylor & Hobson) in my stock, made near here by Rank in the last batches of the 1960's. I wished to enlarge some  6 x 9 negatives and was ready to fit it on to my 6 x 9 enlarger flange when I found it would only turn about one half of a turn before jamming. At this point it became clear that it did fit another flange I had, but had never used. From various other sites I found that Leica screw thread is 39 mm and 26 t.p.inch. Rather a strange definition for a precision engineering company but explained by the background of Leitz in Microscopes which commonly used such threads in Whitworth form over many years. Close examination of the TTH showed it was of 1 1/2 inch diameter and  24 tpi. with a heavily relieved 'lead in' to the thread. I have come across these 'almost right' fittings in the past on an US Leica look-alike, the Perfex, with 39 mm in a very fine thread.

Needless to say, there is no question of the TTH being 'wrong' in any way, it is simply using UK standards for a UK lens!

If you find one do not think of forcing it onto a flange by brute force!