DW 8300 Transiit Level question

[Tony Jester]

Hello. I've never posted before but I have a question. I own a David White
8300 Transit Level that will not stay calibrated when locked into the
"Level" mode. In other words, when locked, if I level the instrument in
both directions, then rotate 180 degrees, the bubble no longer indicates
level. I have had it in the shop several times for calibration and am at my
wit's end. The only way I can use it as a level is to unlock the transit
and "split the difference" on the bubble using the transit adjustment. This
works of course, but takes way to much time when people are sitting around
waiting for me to finish leveling the thing. Is this normal for this type
of instrument? I'm very frustrated with it. What should I do? Thank you.

Tony

[bestafor]

HiHo;
I would take it to some other shop.
It is not normal and easy to correct.
The plate bubble should be adjusted
and any good book on survey will
explain how in the field.

Post by Tony Jester
Hello. I've never posted before but I have a question. I own a David White
8300 Transit Level that will not stay calibrated when locked into the
"Level" mode. In other words, when locked, if I level the instrument in
both directions, then rotate 180 degrees, the bubble no longer indicates
level. I have had it in the shop several times for calibration and am at my
wit's end. The only way I can use it as a level is to unlock the transit
and "split the difference" on the bubble using the transit adjustment.

This

Post by Tony Jester
works of course, but takes way to much time when people are sitting around
waiting for me to finish leveling the thing. Is this normal for this type
of instrument? I'm very frustrated with it. What should I do? Thank you.
Tony

[Tony Jester]

Post by bestafor
HiHo;
I would take it to some other shop.
It is not normal and easy to correct.
The plate bubble should be adjusted
and any good book on survey will
explain how in the field.

Before I took it to the shop, I once adjusted the bubble vile myself when I
was in a jam and that worked (as far as the bubble reading level when turned
180 degrees). But I don't know if that's a good idea. If the bubble reads
level, does that mean the telescope is level? Is it possible for the bubble
to read level and the telescope NOT be level? There is only one shop in the
area. I'd have to ship it somewhere if I wanted to go someplace else.

It would be really easy to simply adjust the bubble vile to elimnate the
error, but does this insure the telescope is also level? Thanks.

-Tony-

Post by bestafor

Post by Tony Jester
Hello. I've never posted before but I have a question. I own a David

White

Post by Tony Jester
8300 Transit Level that will not stay calibrated when locked into the
"Level" mode. In other words, when locked, if I level the instrument in
both directions, then rotate 180 degrees, the bubble no longer indicates
level. I have had it in the shop several times for calibration and am

at

Post by bestafor
my

Post by Tony Jester
wit's end. The only way I can use it as a level is to unlock the transit
and "split the difference" on the bubble using the transit adjustment.

This

Post by Tony Jester
works of course, but takes way to much time when people are sitting around
waiting for me to finish leveling the thing. Is this normal for this type
of instrument? I'm very frustrated with it. What should I do? Thank

you.

Post by Tony Jester
Tony

[C.M.German]

Geesh.......... this is what computers have done for us. An age of
surveyors who don't know how to check out their instruments.

Give me a minute and I'll try to explain

The "Two Peg" method..........

Two pegs are set roughly 100' feet or so apart. Set the instrument close
enough to Point A so the eyepiece barely clears a level rod held on Point A.
With the instrument appropriately leveled, sight through the wrong end of
the scope and obtain a rod reading at Point A. (IT can be done), then obtain
a rod reading at Point B in the normal manner. Determine the difference in
elevation of the two points. Next set the instrument as near to Point B in
the same manner and repeat the process. Determine the difference in
elevation of the two points from this setup.

If the differences in elevation are the same, the line of sight and the
bubble are OK!

If the differences in elevation do not agree, the instrument is out of
adjustment.

And so..........

The true difference in elevation will be the mean of the two differences.
From this value and the Rod reading at Point B, the correct rod reading for
Point A can be calculated. Bring the cross hair to this reading with your
tangent adjustment screw. Accordingly, adjust said scope bubble.

Now I know someone here has a better method...........

CM

[Richard]

Post by C.M.German
The "Two Peg" method..........

I was always taught the plate has to be made level first; that is, it
should be perpendicular to the vertical axis and that axis made
vertical using the leveling screws. Then the level vial is adjusted
to zero at that point, and checked by pointing in all directions where
it should remain at zero. The cross hair does not necessarily give a
level at this point, most likely it is tilted either up or down.

The next best step is the two peg test, and the horizontal cross hair
should be adjusted ( both up and down and rotated) so the level mark
will lie on the cross hair as it is panned from one side to the other
in the field of view.

I don't think the David White is a precision tilting level with a
separate scope level, and it does not seem to be an automatic level
from what I read. Yeah, a review in one of the older basic survey
texts might be in order.

Post by C.M.German
Two pegs are set roughly 100' feet or so apart. Set the instrument close
enough to Point A so the eyepiece barely clears a level rod held on Point A.
With the instrument appropriately leveled, sight through the wrong end of
the scope and obtain a rod reading at Point A. (IT can be done), then obtain
a rod reading at Point B in the normal manner. Determine the difference in
elevation of the two points. Next set the instrument as near to Point B in
the same manner and repeat the process. Determine the difference in
elevation of the two points from this setup.

And, if he has the type of level I am thinking of, he then corrects
the cross hair to have it lie on the proper reading; and checks it all
over again until everything is right. Make real sure the parallax is
dialed out with a good diopter correction for the cross hairs, and a
good focus, by doing the head shake thing.

Otherwise, I agree with you.

[C.M.German]

Yep, Richard... I just didn't want to scare him too much with the over and
over thing but the more the better up to point..... adjust Cross hair,
adjust bubble, adjust cross hair, adjust bubble until you're satisfied.

CM

http://www.needhim.org/

Post by Richard

Post by C.M.German
The "Two Peg" method..........

I was always taught the plate has to be made level first; that is, it
should be perpendicular to the vertical axis and that axis made
vertical using the leveling screws. Then the level vial is adjusted
to zero at that point, and checked by pointing in all directions where
it should remain at zero. The cross hair does not necessarily give a
level at this point, most likely it is tilted either up or down.
The next best step is the two peg test, and the horizontal cross hair
should be adjusted ( both up and down and rotated) so the level mark
will lie on the cross hair as it is panned from one side to the other
in the field of view.
I don't think the David White is a precision tilting level with a
separate scope level, and it does not seem to be an automatic level
from what I read. Yeah, a review in one of the older basic survey
texts might be in order.

Post by C.M.German
Two pegs are set roughly 100' feet or so apart. Set the instrument close
enough to Point A so the eyepiece barely clears a level rod held on Point A.
With the instrument appropriately leveled, sight through the wrong end of
the scope and obtain a rod reading at Point A. (IT can be done), then obtain
a rod reading at Point B in the normal manner. Determine the difference in
elevation of the two points. Next set the instrument as near to Point B in
the same manner and repeat the process. Determine the difference in
elevation of the two points from this setup.

And, if he has the type of level I am thinking of, he then corrects
the cross hair to have it lie on the proper reading; and checks it all
over again until everything is right. Make real sure the parallax is
dialed out with a good diopter correction for the cross hairs, and a
good focus, by doing the head shake thing.
Otherwise, I agree with you.
--
Richard ...

[Tony Jester]

Post by C.M.German
Yep, Richard... I just didn't want to scare him too much with the over and
over thing

It takes a little more than that to scare me. It ain't exactly rocket
science :-)

-Tony-

[Tony Jester]

Post by C.M.German
Geesh.......... this is what computers have done for us. An age of
surveyors who don't know how to check out their instruments.
Give me a minute and I'll try to explain

I'm not a surveyor, I'm an auto mechanic by trade who is building his own
house and therefore needs to use a level fairly frequently. The David White
is the instrument I have so that's what I'm using.

-Tony-

[C.M.German]

Then ignore the intro and use the commentary.......... I hope I was able to
help you.

CM
--
http://www.needhim.org/

Post by Tony Jester

Post by C.M.German
Geesh.......... this is what computers have done for us. An age of
surveyors who don't know how to check out their instruments.
Give me a minute and I'll try to explain

I'm not a surveyor, I'm an auto mechanic by trade who is building his own
house and therefore needs to use a level fairly frequently. The David White
is the instrument I have so that's what I'm using.
-Tony-

[fake]

You need to adjust the bubble. Level it, as usual, in one direction,
turn 180 and adjust HALF of the error out with the BUBBLE adjustment
nuts. Turn back to 0 and re-level, as usual, then back to 180. If the
bubble doesn't remain level, repeat the proceedure until it does. This
requires an adjustment pin that is usually lost, but a small drill bit,
that EXACTLY fits the nut holes, also works. Then you need peg test it
to check the adjustment of the crosshairs.

Post by Tony Jester
Hello. I've never posted before but I have a question. I own a David White
8300 Transit Level that will not stay calibrated when locked into the
"Level" mode. In other words, when locked, if I level the instrument in
both directions, then rotate 180 degrees, the bubble no longer indicates
level. I have had it in the shop several times for calibration and am at my
wit's end. The only way I can use it as a level is to unlock the transit
and "split the difference" on the bubble using the transit adjustment. This
works of course, but takes way to much time when people are sitting around
waiting for me to finish leveling the thing. Is this normal for this type
of instrument? I'm very frustrated with it. What should I do? Thank you.
Tony