Zero’ing dial caliper

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Zero’ing dial caliper

This topic has 16 replies, 6 voices, and was last updated 5 October 2017 at 13:59 by Tim Stevens.

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13 February 2017 at 11:26 #283942
bugbear6502
Participant
@bugbear6502
I have just purchased from eBay a s/h Tesa dial gauge. I am very happy with it, it moves like silk, zero's correctly, and gives absolute consistent readings on repeated measurements.

I have two related questions

1) It is currently reading a "perfect" zero when fully closed, but I would like to know how to adjust this, if needed. On my current (cheap!) GRP Rabone dial gauge, you can simply rotate the dial with the numbers as required, against friction.

2) Related to (1). The current dial face is upside down! This particular gauge face reads 2 mm per full turn.

I can see 2 knurled knobs, and 1 recessed screw (roughly where I've added the red dot).

The upper knob locks the travel. The lower knob has no effect (that I've discovered yet), and I haven't tried undoing the small screw.

Can anyone tell me how to rotate the display dial, or (more generally) how to use this dial caliper?

BugBear
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13 February 2017 at 11:26 #8563
bugbear6502
Participant
@bugbear6502
13 February 2017 at 11:34 #283943
Michael Gilligan
Participant
@michaelgilligan61133
You "should" find that the knurled screw at the bottom unlocks the scale, for rotation.

MichaelG.
13 February 2017 at 11:36 #283944
SillyOldDuffer
Moderator
@sillyoldduffer
Wild guess – is it a left-hand caliper? Being right-handed I've often thought a left-handed digital caliper would make it easier to measure work held in a lathe chuck.
13 February 2017 at 11:45 #283946
bugbear6502
Participant
@bugbear6502
Posted by Michael Gilligan on 13/02/2017 11:34:45:

You "should" find that the knurled screw at the bottom unlocks the scale, for rotation.

MichaelG.

I've loosened that screw, and tried to move the dial. To the limit
of the force I'm prepared to apply, it doesn't move.

It's either the wrong screw, or the dial is stuck.

BugBear
13 February 2017 at 11:56 #283949
bugbear6502
Participant
@bugbear6502
I've found an Amazon document for a Brown & Sharpe product (B&S, Etalon and Tesa are all the same) that says "The bezel lock screw locks the dial and the slider lock screw holds the sliding jaw in position."

Since I know by experiment that the upper screw locks the jaw nicely, the other screw must be the bezel lock. And yet the bezel won't move.

"darn"

BugBear
13 February 2017 at 12:13 #283950
Michael Gilligan
Participant
@michaelgilligan61133
I would next try loosening the recessed screw by the red dot.

… It may have been overtightened [or even replaced] by the previous user.

MichaelG.
13 February 2017 at 12:18 #283951
bugbear6502
Participant
@bugbear6502
Posted by Michael Gilligan on 13/02/2017 12:13:10:

I would next try loosening the recessed screw by the red dot.

… It may have been overtightened [or even replaced] by the previous user.

MichaelG.

Please pardon my ignorance (which is vast); what does the recessed screw do?

BugBear
13 February 2017 at 12:24 #283952
Michael Gilligan
Participant
@michaelgilligan61133
Posted by bugbear6502 on 13/02/2017 12:18:58:

Please pardon my ignorance (which is vast); what does the recessed screw do?

BugBear

.

Typically, it has a plain section on the inner portion, which sits under a ledge on the dial and prevents the rotatable scale falling off. … If it has been substituted, or abused, then it might be locking the scale.

MichaelG.
13 February 2017 at 12:47 #283957
bugbear6502
Participant
@bugbear6502
Thank you.

I just took delivery of the caliper at work; I will investigate further when I get home to my workshop (which includes precision screwdrivers).

BugBear
13 February 2017 at 12:52 #283958
Lambton
Participant
@lambton
BugBear,

I have an identical TESA dial calliper. I have tried it just now and can confirm that you should loosen the bottom screw and then the dial should be movable. On mine the dial moves very easily and smoothly so yours is stuck for some reason. Do not interfere with the two small recessed screws at the top as these are for adjusting out any slack in the slide. A bit like jib adjusters. The large screw at the top is simply a to lock the slide to retain a reading.

hope this clarifies matters

Eric
13 February 2017 at 12:56 #283959
bugbear6502
Participant
@bugbear6502
Posted by Lambton on 13/02/2017 12:52:44:

BugBear,

I have an identical TESA dial calliper. I have tried it just now and can confirm that you should loosen the bottom screw and then the dial should be movable. On mine the dial moves very easily and smoothly so yours is stuck for some reason. Do not interfere with the two small recessed screws at the top as these are for adjusting out any slack in the slide. A bit like jib adjusters. The large screw at the top is simply a to lock the slide to retain a reading.

hope this clarifies matters

Eric

Excellent info – thank you. I hadn't even noticed the right hand recessed screw

BugBear
13 February 2017 at 13:10 #283960
Michael Gilligan
Participant
@michaelgilligan61133
Reading Lambton's note … and looking back at the photo … I realise I may have misinterpreted the red dot !!

I thought it was marking the position of a recessed screw in the rotating bezel.

… If it's one of the two gib-adjusters then please accept my apologies, and leave it well alone.

MichaelG.

.

P.S. these pages may be of interest:

http://www.longislandindicator.com/p97.html

http://www.longislandindicator.com/p44.html

Edited By Michael Gilligan on 13/02/2017 13:23:41
13 February 2017 at 13:22 #283961
bugbear6502
Participant
@bugbear6502
OK ; thanks to all for your information; it looks like my calipers are simply/purely malfunctioning and that the dial is stuck (for whatever reason).

Given that they currently move beautifully, and are correctly zero'd, and very accurate, I will leave well alone.

BugBear
13 February 2017 at 13:56 #283963
Jon Gibbs
Participant
@jongibbs59756
These are Starrett calipers but it might give you a clue… **LINK**

HTH

Jon
5 October 2017 at 11:13 #320111
bugbear6502
Participant
@bugbear6502
Bizarrely – the dial now rotates, albeit very stiff. And I didn't apply extra force. Strange.

BugBear
5 October 2017 at 13:59 #320122
Tim Stevens
Participant
@timstevens64731
Perhaps the reason for the upside down condition is that the caliper is an Australian model?

Jokes are like engineers, the older the better.

Tim
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