Thread Pitch

[carpioboy]

Hi ,
I am trying to identify the thread on the end of a winding stem for a Jaeger-Lecoultre 467/2 movement .
The outside diameter is 1.5 mm but a std 1.5mm thread pitch is not correct .
It could be a Metric fine thread, however i do not have taps and dies for this type of thread and as yet can not find them in my searches .
Does anyone know what thread it should be ?
I can get around the problem by bushing and re tapping the crown to std 1.5mm and using the same thread on the stem . However i would like to keep to the original if possible.
Many thanks 

Jeff
carpioboy

[Geo]

I suspect you need a watchmakers No.4 tap.

Edit: The above is incorrect.

[carpioboy]

Hi Geo,

              I don't know how to put a screw thread on the end of a winding stem with a Tap ?  hehehehe 

 Guess you mis read it .

 Joking aside Geo, i do have a set of taps for watchmaking but they are based around the ISO std pitches. The original thread is not ISO std metric . The 1.5mm std pitch is .350 and the ISO mm fine is .200 (i think). As im sure you know , these watches were made in the late 1930s and there were many threads available at the time .

 Im not a good enough engineer to accurately calculate or identify the correct pitch from the examples that i have, so i was just hoping that someone would know , what it was .

 Thank you for your reply

   Regards 

 jeff 

carpioboy

[Geo]

It's an age thing Jeff, it's been a long day!

[Geo]

Please ignore my previous comment regarding the No.4 tap, I was having a brain fart!

Here's a list of information relative to Bergeon taps and dies.

No. Dia. x Pitch drill. Sizes in mm

1 0.30x0.075 0.24

2 0.35x0.075 0.28

3 0.40x0.100 0.32

4 0.45x0.100 0.37

5 0.50x0.125 0.40

6 0.55x0.125 0.45

7 0.60x0.150 0.48

8 0.65x0.150 0.53

9 0.70x0.175 0.56

10 0.75x0.175 0.61

11 0.80x0.200 0.64

12 0.85x0.200 0.69

13 0.90x0.225 0.72

14 0.95x0.225 0.77

15 1.00x0.250 0.80

16 1.05x0.250 0.85

17 1.10x0.250 0.90

18 1.20x0.250 1.00

19 1.30x0.300 1.06

20 1.40x0.300 1.16

21 1.50x0.350 1.26

22 1.60x0.350 1.32

23 1.70x0.350 1.42

24 1.80x0.350 1.52

25 2.00x0.400 1.68

[carpioboy]

Hi Geo ,

                    Had a good laugh at your comments as i also suffer from the age thing ( in lots of ways ) hehehe

 Thanks for the info . Its in line with taps and dies that i do have .

 I have found that the thread on the end of the stem , although 1.5 mm outside diameter, is definitely not .350 pitch so perhaps it is prior to standardisation and is in fact metric fine or perhaps one of the many different threads used by the watch houses of the time .

 Without access to the tech drawing or in absence of someone's definitive knowledge i guess i'm stuck. Plan B looks good now and i will finish turning the stem and thread it using the std Bergeon 1.5mm die. I will then bush and re tap the crown to suit.

 Thanks again for your input  I appreciate it.

 Regards 

    jeff

carpioboy

[StuartBaker104]

I came across a table on a forum once which I believe was from Fried's watch repairer's manual that compared stem tap sizes. I can't find it now, but no doubt someone out there has uploaded a pdf...

[Alaskamick]

Here is a copy from the book mentioned.IMG.pdf

 

Unfortunately it's upside down bot I'm sure you can overcome that by standing on your head  :D

Edited October 30, 2015 by Alaskamick

[carpioboy]

Hi All,

          Thanks to everyone for the replies.

 Alaskamick,, no problem to stand on my head , ive done everything else to get this watch fixed so why not .lol

 

 Appreciate your help 

 Regards 

   jeff