WILD T=3 advice

no help here

Never used a T-3, but what you've described almost makes me think there might be a 'floating' plate that is similar to the horizontal circle.

I think Wild instruments read zenith angles, but I can't think of any scenario where horizontal would read near 45d.

T-3

45° is the reading on the vertical circle with the vertical circle face-left and with the scope pointed straight up (which you can't because the length of the scope won't let you.)

The vertical circle is derived by the SUM of the face-left and face-right readings as I remember.

What happens when you sight something, read the vertical angle, then invert the scope and read it again?

In other words, how does it double angles?

Dugger

The vertical circle also has a split bubble for leveling.

I think if you want to double it you measure it again.

(We used to do six vertical sets and sixteen positions of the horizontal.)

hi
contact sokkia in montague road, south brisbane, australia, i dont have their card here in china now, the service agent/repair manager collects old instruments, he has t-3 upstairs in his office, its a beauty, and he is a friendly guy,has had the business for 30 years or more.
cheers david

T-3

Even though the instrument looks like it's never been used, it's possible someone has attempted maintenance or calibration and the vertical circle was positioned improperly after being removed. I'm not familiar with the inner workings of the T-3 but the typical mounting system for a glass circle is it will be on a metal collar and secured on the metal collar with a spring plate. The collar will be attached to the axis with four screws in holes that are evenly spaced i.e. at 90 degree positions. From your description it seems possible someone has removed the vertical circle and positioned it incorrectly when assembling it. The way a glass photo etched circle is attached allows for movement to center the graduations. I think some manufacturers have enough faith in their mounting system to use the spring plate to secure it in position. Others may use a little optical cement to provide additional security once the circle is properly centered. Optical cement is a special adhesive even though it may look like hardware store epoxy. Glass and metal have different coefficients of expansion and contraction and optical cement takes that into account. Use epoxy or superglue and the glass may be stressed enough to crack.

If you don't have a military manual for the T-3 you might want to take a look at this:

http://www.liberatedmanuals.com/tm-5-6675-231-15.pdf

Covers operation and maintenance. Instrument manufacturers had to provide more than the standard commercial operators manual to the military. I'm always amused by the specific instructions in these manuals for destruction of the instrument so it's not useful to the enemy. I suppose you have to cover every contingency.

Before the age of the Internet one could order copies of many of these manuals and guides from the Army at little or no cost. I think they came from a depot in St. Louis.

If you want to be sure your instrument is in proper working order and avoid heartbreak and tears, I suggest looking for a repair shop with a technician familiar with the T-3. Maybe even with factory training and tools. Must be a few still out there.

T-3

I just noticed that above I stated the vertical circle is the sum of the two readings, circle left and circle. I meant the vertical angle.

And 135° on the vertical circle points to the nadir, so the vertical circle isn't installed wrong.

From the T3 manual:

"Reading the vertical circle is slightly different, because due to its smaller diameter it contains only half the number of graduations of the horizontal circle. As the numbering of the intervals is the same it gives half its true angular value."

How to read:

"The target is sighted first in the Face Left position, so that the horizontal cross-hair and the target image coincide, giving a reading A(sub L) after the bubble of the vertical circle index level has been centered. Then pointing is made in the Face Right position giving the reading A(sub R). Now, due to the half value graduation and equal numbering of the vertical circle of the T3, the angle of elevation or depression together with the correct sign, is obtained immediately after subtracting the Face Right reading from the Face Left reading."

Note that the resulting value is a VERTICAL ANGLE, not a ZENITH ANGLE, and is free from index error.

This goofy-sounding vertical circle system makes a lot more sense to the user when using it with the Astrolabe attachment, as I recall ...

T-3

Thanks for the great link. It is a much more comprehensive manual than the consumers version. Now I even know what to do to disable or destroy the thing when I run out of ammo . Thanks also to everyone who replyed and emailed. The actual solution to my problem is much easier than I originally thought. The vertical is reading one-half the true zenith value. When it's level for example it reads 45 degrees x 2 = 90 from zenith. Reversed it reads 315 degrees x 2 then minus 360 = 270 degrees. I don't know why this was so puzzling...... anyway problem solved .... now back to pulling weeds.

T-3

I never used one for pulling weeds.

Are they good for that?

T-3

yes you can pull weeds twice as fast when you double center.

T-3

Actually now that I am a retired surveyor... my new most of the time job is gardening. I have never had the time to have a proper garden and this year I went a bit overboard (125 strawberry plants, lettuce, radishes, carrots, beets, tomatoes, potatoes, spinach, asparagus, squash, cucumbers, watermelon, cantalope, and for my grandson... pumpkins, also 20 raspberry and 10 blackberry bushes) and it seems like all I do is fight off weeds.