Pocket watch crown

[KellyZ]

Hello all,

I am working on a Tissot pocket watch (model 501, calibre 43) which dates to 1952. It was missing the crown and stem. I was able to source a new stem for the movement and confirm it fits correctly. However, I am having a devil of a time trying to find a crown that fits. The stem has a diameter of 1.45mm and all the parts houses I have checked seem to primarily have crowns to fit 0.90mm and 1.20 mm stems and a small number to fit 1.40mm stems. Would the 1.40mm crowns work or am I missing something here? Other relevant dimensions my application are case tube OD of 3.60mm and I think an overall crown diameter of ~ 8mm would be in good proportion for the watch case. Any advice would be appreciated. Thanks.

[JohnR725]

It would be nice to have pictures so we know what were looking for to help you out.

 

 

[KellyZ]

I can’t provide pictures of something I don’t have. As I stated in my original post, the crown was missing.

[LittleWatchShop]

You can show us a picture ov the case.

[KellyZ]

As you wish, please see attached

[KarlvonKoln]

This may be a shot in the dark, but would you happen to have a die plate (for threading screws) that you could use to measure the tap size of the stem?  It will give us a number we can use.  I could dig through my store of old crowns.  Yours will be trapezoidal ("pumpkin" as opposed to "onion").

I got to thinking, if you had the tap and die set, then you would probably know to locate a large enough crown to tap to size.  Oh well.

Either way, it can be done.  If a crown can be found that is a good fit for the pendant and its sleeve, it can be tapped to the correct thread size if need be.  I have done it before.

[LittleWatchShop]

I have a few trapezoidal crowns in my box-o-crowns. I will make some measurements later today.

[KellyZ]

I don’t have a die plate unfortunately. I do have a tap and die set that I got a deal on some time back and have never used. When I get home, I will check what sizes I have and report back. Thanks.

[LittleWatchShop]

Here is what I have.

[KellyZ]

That looks like a good match and I think he 7.82 diameter would be in proportion to the rest of the case. One question… Could you measure the overall height of the crown, including the threaded part  that sticks out on the bottom? I just want to make sure it won’t interfere with the bow vertically. If the dimensions are in order, is this something you would be willing to sell? Thanks

[JohnR725]

I have a website even look up what Size this is as there's sort of standards

https://blog.esslinger.com/stem-tap-mm-size-cross-reference-chart/

Then the human list pocket watch crowns

https://www.esslinger.com/pocket-watch-crowns/

 

[LittleWatchShop]

51 minutes ago, KellyZ said:

That looks like a good match and I think he 7.82 diameter would be in proportion to the rest of the case. One question… Could you measure the overall height of the crown, including the threaded part  that sticks out on the bottom? I just want to make sure it won’t interfere with the bow vertically. If the dimensions are in order, is this something you would be willing to sell? Thanks

Sure

[KellyZ]

Thanks for all the replies.

LittleWatchShop, I took some measurements and I dont think there would be any issues with vertical clearance. After thinking about it, my concern with that crown would sit on top of the case tube and even if I cut the stem length carefully, there would still be a gap which would allow dust and water ingress. I am thinking I need a crown with no post and an opening slightly greater than 3.60mm so that it can fit over the case tube to minimize that. Please let me know if you disagree.

JohnR725, thanks for the links. I did come across those while doing my research but they (and other pages I found) only go in .1mm increments, 1.1, 1.2, 1.3, 1.4, 1.5 etc. My stem has a diameter of 1.45mm, checked with both digital calipers and micrometer. Is there a standard to step up or step down to calculate the tap needed?

KarlvonKoln, the largest tap in my set is 1.2mm so I dont have one big enough. I did look around and individual taps can be had without spending a great deal of money. I would not be opposed to investing in one and trying your suggestion. The learning experience would be good if nothing else. The same question applies though... what size would I need. I do have a couple of crowns in an assorted box I have that would be good candidates.

 

[JohnR725]

5 hours ago, KellyZ said:

would allow dust and water ingress

You obviously haven't seen a vintage pocket watch. It's amazing what will get past the crown and as far as I know pocketwatch crowns are never waterproof although usually pocket watches don't get in water even though you will find Rusty pocket watches because the entire case is not water resistant at all

5 hours ago, KellyZ said:

My stem has a diameter of 1.45mm, checked with both digital calipers and micrometer.

The funny thing about the screw thread diameters are they actually the diameter you measure? For instance is a website below like this one

https://www.windingstems.com/tissot.php

So we go there and we can look up your stem and then we get specifications. They have a different dimension than you have. Then just because I was curious I took the time to look up the bestfit stem It's specifications, and it has the same thing 1.5 mm is the diameter of the threaded part.

Then I'm being hunted by an image of pocket watch crown styles just can't remember where I saw that. But did find you this link may be a find something there.

http://www.julesborel.com/products/watch-case-parts-crowns-crowns-pocket-watches

 

[KellyZ]

Definitely no expectations of waterproof, but I think an open gap (as opposed to a “S” shaped gap with a flush crown) would be just a little worse. I think with a straight gap, just the lint in your pocket would gum up the watch in short order. Thanks very much for that windingstems.com link… what a great resource, duly bookmarked for future reference. Taking a quick look, 1.5mm crowns don’t seem to be available from the big parts houses but I will spend some time searching on smaller suppliers. If I don’t find something suitable, I will invest in a 1.5mm tap and see what I can transform. Either way, I will report the result here.

Edited November 22, 2022 by KellyZ
Mistaken word

[praezis]

You could tap a 1.4 thread to 1.5: both use the same pitch.

But imo you already got a good offer above?

Frank

[KellyZ]

For the moment I decided to pass on that as it has an extended pipe which I think is not optimum. At least I now exactly what to look for. I really did not understand the relationship between diameters, tap sizes and treads.

[JohnR725]

7 hours ago, KellyZ said:

Taking a quick look, 1.5mm crowns don’t seem to be available from the big parts houses but I will spend some time searching on smaller suppliers.

Just a reminder about material houses.  Today 99% of everyone on this group the material houses an online business that you go you search the either have it or they don't order it and it shows up in the mail. But is that the way all material houses operate?

One of the problems is that not every single material house has converted to online. Then even some of the big material houses are not 100% online because it's hard to be 100% online especially if you have older stuff in limited quantity or you've acquired other material houses it's hard to integrate it all together. This means that there is a lot of watch material out there that isn't online.

 

Simplistically this means your crown exists it's out there somewhere but you're probably not going to find it online. Though have to inquire and in your profile no idea where you're located at all. In the US there are still physical material houses that do business with walk-in trade for instance or email trade. Even some of the online material houses if you read the fine print they will say email. But just as a reminder it depends on the particular material house as to how eager they will be to help you and some him get really cranky about wasting their time.

[KellyZ]

Understood. I am in the US (Maryland) but am still new to this game so I will be learning which companies are less "cranky" as you put it when engaging in non-online business. Before I started going down that road though, I wanted to determine exactly what was needed (which I now have). I figure most of them would be impatient if I didnt. In fairness, they are there to make money, not to help me learn.