Jewels identification

[luiazazrambo]

Hello Black- and Locksmiths, Clock and Watchmakers,

could someone help me to understand the numbers for these packages please? They contain jewels the first one is 06 405/18 L40 with a hole in it diameter is 0.76 mm. The other one has cap jewels numbered as 06 163/20 L50 diameter is 1.1 mm. I have a lot more of these little packages, but I cant seem to find the relation between the numbering and the diameter or even the type of the jewel.

Take care,

Lui

[jdrichard]

1 minute ago, luiazazrambo said:

Hello Black- and Locksmiths, Clock and Watchmakers,

could someone help me to understand the numbers for these packages please? They contain jewels the first one is 06 405/18 L40 with a hole in it diameter is 0.76 mm. The other one has cap jewels numbered as 06 163/20 L50 diameter is 1.1 mm. I have a lot more of these little packages, but I cant seem to find the relation between the numbering and the diameter or even the type of the jewel.

Take care,

Lui

First number is the diameter and second number is the hole diameter. Like 163/20

[luiazazrambo]

9 hours ago, jdrichard said:

First number is the diameter and second number is the hole diameter. Like 163/20

Unfortunately its not the case. And the cap jewel has no hole. They are 0.76mm and 1.1mm so 0.76/1.1 should also match 163/405 should they use something else than a metric system, but 405 is more than double of 163.

[praezis]

Seems they are just catalog numbers without size relation.

But should be no problem: you have large numbers of the same size, so just measure one jewel of each package.

Frank

[spectre6000]

Watching and learning here.

Measuring the outside seems easy enough (though I hate handling bare jewels like that; sproing city), but how does one measure the hole diameter? Are there expensive gauges out there one would need to hunt down to accomplish this?

[Plato]

46 minutes ago, spectre6000 said:

Are there expensive gauges out there one would need to hunt down to accomplish this?

Bergeon 30033

[Marc]

1 hour ago, spectre6000 said:

Are there expensive gauges out there one would need to hunt down to accomplish this?

You could always improvise by inserting a fine tapered pin into the jewel until it starts to bind and then measure the taper at that point using calipers or a micrometer.

I have seen someone on Youtube using a gauge that worked on this principal, only the tapered pin was mounted in a sliding sleeve. You put the pin into the jewel as far as it would go, then as you continued to push the pin was pushed back into the sleeve until the jewel came up against the front of the sleeve. A pionter on the back end of the pin could then be read against a scale on the sleeve.

Probably a terrible description so if I can find the video again I'll post a link.

Here it is, about 25 seconds in.

 

Edited February 3, 2022 by Marc
Added a link.

[luiazazrambo]

I was actively looking for this in the last two years or so because I just knew that this moment would come in my life when I needed it, I only saw it twice one on the UK and one on the German eBay site, i was hoping that I could put my hands on on a used one relatively cheap, but my hope was crushed by reality. Probably I missed another one or two. The one I was looking for was made by obama. Not the former US president, but I believe a German company? I also saw a jacot tool from them once.

Here we go I just found one jacot tool from them: obama jacot tool

And this is the jewel gauge: obama jewel gauge

I think the one shown in the video above is also an obama jewel gauge, its rare like unicorn poo.

Edited February 3, 2022 by luiazazrambo

[luiazazrambo]

One of the envelope got dates on it. So these are form 1963. More than 70k jewels together.