I took delivery today of a 30" Gurley transit that I bought on eBay:
Although I used a similar 20" model on a few occasions early in my career, I can't say I'm familiar with open-standard vernier transits. This one appealed to me because we're about the same age -- it was manufactured in 1952, while I was manufactured in 1953 -- and it appeared to be in original retired-from-service condition. My inspection so far indicates that latter to be the case. It's definitely work-worn, but otherwise in pretty good operational shape.
My plan is to clean, lubricate and adjust it, but not try to restore its finish.
One thing that obviously needs adjustment is the compass counterbalance, which is set for a very different locale. What's not clear to me is the means of accessing it. I assume the glass cover comes off, and I see a small setscrew in its side, but loosening it didn't release retaining ring. I thought I'd ask for advice here before I apply pressure to anything.
I also bought a PDF copy of a 1948 Gurley transit manual. At the end of the section on compass care, the following appears in italics:
Hold a dip needle in the plane of the magnetic meridian. Do not try to use a dip needle to locate buried treasure.
Nice to see that someone had a sense of humor.
The set screw locks the lens frame in place
That frame is usually like an old watch face and is fine threaded.
Yes, the glass retaining ring should unscrew. If it has set in place for 60 years it may be difficult so you may need to apply something for leverage. While this may leave a small "ding" in the ring, something that has worked for me on many occasions is to make a small notch in the ring that you can catch a screw driver blade in and then lightly tap it with a small hammer. Once you break the oxidation seal it should come off with hand pressure.
Another thing that has worked is an old fashioned jar lid opener that you can grip it on both sides. Not all styles will fit, but some will.
I will also observe that that is the first Gurley I have seen with a set screw to hold it in place.
Good luck on a nice find.
That's a handsome instrument.
The turning of the compass lens ring might be accomplished with one of those rubber disks that kitchenware stores sell for opening jar lids--or in certain instances, as potholders. I've used them a time or two on older instruments, and they don't always work, but whether they do or not, they leave no scar. The trick is often to decide where and how to "rigidify" the whole instrument, if you don't have a stand. A tripod in yielding turf has worked for me.
Cheers,
Henry
I did some gentle tapping with a small hammer and a punch tipped with plastic. While that undoubtedly helped to loosen the age-related stickiness, the bezel ring is so tightly nestled among the standards that I wasn't able to get any kind of grip on it. I was reluctant to use the circumferential punch technique, but after scratching my head for awhile I remembered a 99-cent mechanic's suction cup that I bought as a toy for my son years ago. I affixed that to the bezel glass and presto! instant handle.
I don't know if the glass is intentionally stuck to the ring or if it's another age-related sticking situation, but the suction cup worked like a charm for getting the bezel off and back on. The needle is now nicely balanced for my location.
Good suggestion
Hadn't thought of anything like that. I'll have to keep that in mind.
And, yes, most glass is sealed in place enough that it won't twist.
The last person to clean the instrument probably applied a thin coat of something to serve as a waterproof seal between the bezel and the glass.
Usually soaking in hot water will separate the two. If they are clean, I would leave them together.
That is really good. I appreciate knowing about it!
Cheers,
Henry
Back in the late 70's I used the old K&E transits for almost everything. I wouldn't mind getting one of those just for old times sake. Nice find on the Gurley! The patina is something you want to maintain I would think.
:good:
That's cool Jim!
Nice Gurley. Here are the 2 I have.
I've noticed that the scope on mine doesn't look like any of the others of which I've seen photos. The objective end has a long taper, and the eyepiece end is large and blunt. I've looked on the web for reference works documenting post-1909 Gurley instruments, but haven't found anything. (There are some books and web pages devoted to pre-1909 guns.) If anyone knows why they would have offered such different scope designs, I'd be interested in hearing about it.
Give me a couple of days and I'll go through a bunch of my Gurley stuff and see what I can tell you.
BTW - Your $0.99 suction cups are now $2.99 at Harbor Freight. 🙂
I sent you an email through BeerLeg. Please respond as requested.
If you look closely at the instrument on the right in Thomas Smith's photo the scope tube looks almost identical to the photo you posted except his appears to have a slightly larger eyepiece. Could yours be missing part of the eyepiece?
> If you look closely at the instrument on the right in Thomas Smith's photo the scope tube looks almost identical to the photo you posted except his appears to have a slightly larger eyepiece. Could yours be missing part of the eyepiece?
It looks like mine is missing a decorative/protective ring around the eyepiece lens:
The eyepiece is overall more bulbous than most, and the objective end has a very different taper.
> Give me a couple of days and I'll go through a bunch of my Gurley stuff and see what I can tell you.
>
> BTW - Your $0.99 suction cups are now $2.99 at Harbor Freight. 🙂
>
> I sent you an email through BeerLeg. Please respond as requested.
Sorry about the suction cup price increase -- it's been a few years since I bought the one as a toy.
I did send email. Thanks very much for sharing!