Dial caliper
engineman
closed and the O at the top it reads .015.
He can loosen the screw that holds the dial and rotate it to zero but
he'd like to have it zero out at the top.
I don't think the rack can be moved that much.
How can he reset it?
Engineman
Lewis Hartswick
...lew...
sta...@prolynx.com
It doesn't really matter WHERE 0 is, just that it can be zeroed, and
more to the point, the tips aren't bent after being dropped. Some of
the better imports had a narrow shim supplied in the box that could be
used to move the pointer, the pinions on those are spring loaded so
just wedging them out of mesh with the rack would move the pointer.
Not sure if they're all built that way, but it works for those. The
shim is a couple of thousandths thick or so and narrow enough to fit
in the rack groove. I've also seen some where the back of the slider
was held on with some fine screws, pulling those will let the slider
come off forwards, reassembly will be up to you! If you're lucky, you
won't need watchmaking tweezers to reassemble.
Stan
Wild_Bill
top, it just seems much easier to read more quickly.
Reading a clock wouldn't be as easy (at a glance) if a different number was
placed at the top.
After a friend borrowed a dial caliper, it didn't read zero at the top, but
it turned out to be a slight burr at the tip of one of the jaws, from rough
handling, possibly where it hit if it was dropped.
If the bezel can be removed, the easiest way would probably be to gently
pull the pointer off and reset it at zero.
I did a reset the hard way a number of years ago, and can't remember the
details now, but it took more than a few tries.
I think I removed the stop at the end, and ran the entire dial assembly off
the scale, then put it back on to see where the pointer stopped when closed.
I think I eventually removed the screws from the rack, and moved the rack to
get the desired position.
If I hadn't approached it as a challenge, it wouldn't have been worth the
trouble.
It still works fine now, but I use a digital more frequently.
--
WB
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"engineman" <engin...@aol.com> wrote in message
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Jon Anderson
down the back of the dial housing, perpendicular to the rack. They come
with a rectangular wire that you slide down this groove, which pushes
the pinion away from the rack. You set the pointer to 12 o'clock, insert
the wire, then slide the jaws closed. But this only works in .025
increments on any caliper I've seen.
For others, I have some fine tipped curved tweezers. I remove the
crystal/bezel, which can be frustrating on some imports, then gently pop
the needle off the shaft, being careful to lift only under the needle's
hub and not on the needle itself. Can take a surprising amount of force,
but I've never damaged anything doing this. Make sure the jaws are
clean, close them, and press the pinter back on at 12. Not a big deal
really.
Jon
Snag
I had that problem with my Chinese caliper . I loosened the gib screws on
top enough that the pinion was disengaged from the rack and re-adjusted it
by trial and error . Not that it did much good , that caliper lives on the
lathe and/or mill , and it has a habit of attractin' swarf .
That's why I got digitals ...
--
Snag
Digital Rocks !
spaco
a little fooling around to get the needle exactly back to "12 o'clock"
if you do it that way. Chances are good that he'll drop it again, or
that a piece of crud will get on the rack at some time, causing another
move from zero.
Pete Stanaiits
----------------
Larry Jaques
<engin...@aol.com> scrawled the following:
There are small copper reset keys for most calipers, E. One of the
guys here sent a couple to me the last time my dial went wonky.
--
Imagination is the beginning of creation. You imagine what you desire,
you will what you imagine and at last you create what you will.
-- George Bernard Shaw
Lewis Hartswick
> I did a reset the hard way a number of years ago, and can't remember the
> details now, but it took more than a few tries.
> I think I removed the stop at the end, and ran the entire dial assembly
> off the scale, then put it back on to see where the pointer stopped when
> closed.
> I think I eventually removed the screws from the rack, and moved the
> rack to get the desired position.
> If I hadn't approached it as a challenge, it wouldn't have been worth
> the trouble.
>
> It still works fine now, but I use a digital more frequently.
>
How in the world did you get the "anti-backlash" spring loaded
gears back in correctly. That was the problem I had with the
one from school I tried to fix. It's still setting on my desk
a few years later. :-)
...lew...
Jon Elson
If not, you can make up such a thing. You open it up to the maximum
width, and then the tiny pinion gear is near the tail of the beam.
You can work the thin sliver of shim under the pinion, and make it skip
a couple rack teeth as you move the jaw. When you get it skipped the
right number of teeth over the rack, it will reset the pointer to
point where you want it to.
It is sometimes easier to do this when you remove the stop on the end
of the beam that prevents the slide from coming off.
Jon
Jon Elson
> If the bezel can be removed, the easiest way would probably be to gently
> pull the pointer off and reset it at zero.
>
Without the correct tool, a Jeweler's watch hand puller, you can break
the end off the pinion. I wouldn't even try this on a Chinese caliper.
Jon
Jon Elson
> How in the world did you get the "anti-backlash" spring loaded
> gears back in correctly. That was the problem I had with the
> one from school I tried to fix. It's still setting on my desk
> a few years later. :-)
I've never seen a dial caliper with an anti-backlash spring.
I have seen that in 1" dial indicators, and you can wind up the
spring from the back of the indicator before reinstalling the plunger.
If some calipers have springs, I'd guess it would only be the more
expensive Fowler, Mitutoyo, Brown & Sharpe, etc., not the Chinese
ones.
Jon
DoN. Nichols
> A friend has a Chinese made dial caliper that he dropped and now when
> closed and the O at the top it reads .015.
> He can loosen the screw that holds the dial and rotate it to zero but
> he'd like to have it zero out at the top.
> I don't think the rack can be moved that much.
I don't think so either.
However, what probably happened is that the pinion gear bounced
out of mesh with the rack, and skipped one tooth before re-engaging.
There *may* have been a tool for fixing that problem (which occurs
from time to time -- sometimes because of chips getting into the rack).
It would be tucked into a slot in the foam lining in the box in which it
lives.
It is a thin flat spring with a wider grip surface which can be
worked into where they mesh to disengage them and skip them to a new
mesh point. It may take a few tries to reach the correct point.
*Or* -- you could remove the screws holding the carriage
together, disengage the pinion and reassemble -- trying a few times
until it lines up again.
> How can he reset it?
Two suggestions above. Both require a fairly delicate touch,
and the latter a workplace which makes it easy to capture the screws and
such -- something like a cafeteria tray.
And -- this can happen with other brands as well -- even
Starrett.
Good luck,
DoN.
--
Email: <dnic...@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
DoN. Nichols
Convenience in reading, mostly.
Enjoy,
Wild_Bill
had experience working with small mechanical assemblies, so the challenge
didn't seem impossible, but since I hadn't taken a dial caliper apart
before, I didn't know what I was doing.
Take an old dial indicator apart, and if that goes well, try fixing the
caliper.
If it's an expensive caliper, maybe send it out for repair.
Long Island Indicator Repair has been recommended here in RCM in the past,
for repair parts.. their repair flat rate for a 6" is $65, up to $125 for a
12" model.
--
WB
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"Lewis Hartswick" <lhart...@earthlink.net> wrote in message
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