TM 5-6300-3, Transit Engineer 1' reading, Dietzgen models

[Dave Karoly, PLS]

I inherited my Father's 1' Dietzgen 6100 series transit. I obtained a copy of the referenced U.S. Army technical manual dated February 1956 which is for Dietzgen models 6024CFS and 6150S. The serial number of my transit indicates it was manufactured in roughly 1971.

It is an interesting booklet; it covers how to completely disassemble and reassemble the instrument but I have no intention of doing that. It also has a paragraph on how to destroy the instrument to prevent it from falling into enemy hands.

The only issue I have is the optics are slightly clouded. The booklet covers how to remove the eyepiece but I'm kind of reluctant to do that. It cautions against disassembling the lens assemblies because that has to be done in an optical laboratory.

The compass needle is balanced for Arizona; the counter weight needs to be moved south a little bit for Northern California but I haven't been able to remove the compass box cover. I think it simply unscrews but I am not completely sure of that. It's on there pretty tight probably because it hasn't been removed in 30+ years.

The checks I have done indicate the Transit is in good adjustment.

[land butcher]

Cool,
The lenses probably accumulated dust over the years.

When I started surveying a company I moonlighted for had bought a military surplus T-2. It had been stored in Panama and every few years had to have the mold removed from the sighting passages. LOL The owner complained that it was costing more to clean than he paid for it. Oh, and it was in mils, which was actually easier to use than degrees.

[Tom Herrin]

Cloudiness in the optics could be fungus on the glass in addition to dust. I've read that this can sometimes be cleared up by getting bright sunlight into the lens (check the internet for more info on this). If that does not work, it is a pretty involved job to get the optics cleaned, sometimes involving things like repolishing the glass surfaces (special tools and techniques for this).

I would not mess with disassembly of the optics, unless you find some really detailed 'how to' info somewhere specific to your instrument. The manual you have already does sound like a start, but you may have to take apart 'lens groups' which is probably beyond the scope of the manual you have. Working on taking apart the lens assemblies can be dicey. Internal glass surfaces are often easy to scratch; its easy to get a lens element reversed when putting things back together; hard to keep dust out, the list goes on. Its very easy to end up with an unworking optic when you are done. Not trying to discourage here, just urging some caution in the approach.

My experience is working with older Nikon camera lenses (1960's and 70's vintage), which I experimented with at the time because the lenses were of little value and not working anyway. I was about 50/50 on my sucess rate. I've not played around with anything survey instrument related though.