Pivot Gauge

[bobm12]

Hi all,

 

Do you know how to properly use this gauge for pivots?

 

 

If there is a tutorial or a hands on sort of picture sequence it would be super! I appreciate the help and thank you in advance.

 

Cheers

 

Bob

[Marc]

I don't think that that is a pivot gauge at all.

It looks to me like an old mainspring thickness gauge which you poke the old spring through at the wide end of the slot then slide it towards the narrow end. When it can go no further you read off the thickness from the scale where the spring stops.

I don't think that this would be any where near precise enough for pivots.

[Geo]

Oh, here comes a wee disagreement Marc. It's a pivot gauge out of a Jacot Tool Set. You slide the pivot along the groove until it stops at the narrowest part then read off the diameter.

Edited January 23, 2015 by Geo

[bobm12]

Excellent, yes, Geo got it.

 

That's what I was doing actually but I saw a vintage ad where they use broaches to "transfer" measurements instead of directly use the pivots. Weird though since using the pivot directly seems more accurate but I just wanted to be sure. Thanks guys.

 

Cheers,

 

Bob

[Marc]

Geo I stand corrected.

 

However, below is the possible cause of my confusion.

 

 

These are a few of a whole bunch of gauges that I have picked up over time.

The three on the left are most definitely mainspring gauges with notches along the side for measuring the height and the tapered slot in the middle for thickness. The one top left also has a scale for measuring the barrel diameter (others I have use a  graduated series of engraved circles for the same purpose).

 

The three on the right I had always assumed were simply spring thickness gauges which were used along side a separate gauge that was graduated for height and barrel diameter only (I have examples of these too).

 

I have only ever encountered pivot gauges of the variety that comprises a series of calibrated holes in a plate (jewelled in the better quality examples) into which the pivot of a staff or arbor could be placed and the correct side shake taken into account according to how far it was able to incline from the vertical.

 

I don't have a Jacot tool (yet) so haven't come across the tapered slot as used in that application.

 

Thinking about it though, the calibrated hole type of gauge is what you would use when selecting an appropriate jewel for a given pivot. It may however, not be an appropriate measure for selecting the correct bed to use in the Jacot tool runner for burnishing a given size of pivot, and indeed in that application the degree of required precision may well be a little more forgiving.

 

So I would say more an instance of enlightenment rather than disagreement, and I always enjoy enlightenment  :)

 

Now all I have to work out is wether the three gauges on the right are for springs or pivots, or even both!!!

[Geo]

I was sure you were thinking of these gauges. Thanks for the above post, it I'll let others know what type of antique gauges are available. :)