Jump to content

Fitting A New Watch Stem.

Geo

By Geo
in Your Walkthroughs and Techniques

 Share

Recommended Posts

Geo Distinguished Member

Geo

Posted
Posted

When fitting new stems to watches I use these tools :-

1-1.jpg

Digital calipers,

Fine grade diamond lap

Wire cutter

Pin vice

Now for fitting.

(1) Hold the stem in the pin vice and screw on the crown tightly by hand.

(2) With the movement fitted correctly in the case, insert the stem until it locks in place. Now measure the gap between the case and the underside of the stem. In this case it is 2.16mm.

2-1.jpg

(3) Subtract 0.2mm from this size and this will give the amount to remove from the stem. In this case it will be 1.96mm which will give 0.2mm clearance below the crown when fitted to the watch.

(4) Now remove the crown from the stem and hold the stem very tightly in the pin vice, then place the pin vice and stem between the jaws of the digital calipers then zero the calipers.

(5) Remove the calipers and without touching the zero button set them to minus 1.96mm. THEN RE-ZERO THE CALIPERS AT THIS LENGTH The wire cutters are now used cut off the excess thread leaving a small amount to be filed to the exact length.

(6) All that is required now is to dress the stem with the diamond lap a little at a time until the calipers read zero.

3-1.jpg

(7) Finally screw the crown on tightly and it should be ready to fit to the watch without further adjustment.

5-1.jpg

I find that this method cuts down on trial and error.

FOR SCREW DOWN CROWNS.

A) Screw down the crown tightly onto the case without the stem and measure the distance nbetween the bottom of the crown and the case.

B ) Screw the new stem tightly into the crown, then insert into the watch until it engages and locks into the movement.

C) Press the crown down firmly as far as it will go and hold it there.

D) Using the vernier callipers, measure the distance between the bottom of the crown and the case.

E) Subtract the size determined in (D) from the size measured in (A) then subtract a further 0.15mm from this size. This is the amount to shorten the stem by. This should allow the crown to screw full home without compressing the stem too tightly between the movement and the inside of the crown.

F) Cut the stem leaving it slightly longer than the size determined in (E), and dress down to size using the diamond lap and vernier callipers as described in the original post.

G) Screw the crown onto the shortened stem and check fit and function, before using a tiny spot of Loctite 221 to secure.

Click here to view the article

  • Like 17
Link to comment
Share on other sites
Geo Distinguished Member

Geo

Posted
  • Author
Posted

OOPS, I forgot to say the calipers had to be re-zeroed again!

(5) Remove the calipers and without touching the zero button set them to minus 1.96mm. THEN RE-ZERO THE CALIPERS AT THIS LENGTH The wire cutters are now used cut off the excess thread leaving a small amount to be filed to the exact length.

Please edit this into the original post if possible Mark.

  • Like 1
Link to comment
Share on other sites
SeikoWatch Super WRT Addict

SeikoWatch

Posted
Posted

Thank you Geo..For my part I purchased the same type of stem and I measure the same length and I cut and I file the end of the threads of the stem. for me, this solve the problem..I'm lucky because it has never happened to have a watch with a piece of the stem. It is also rare that I buy a watch with a broken stem..Sorry for my bad english ;) your explanations are the best..

Link to comment
Share on other sites
Mark Distinguished Member

Mark

Posted
Posted

OOPS, I forgot to say the calipers had to be re-zeroed again!

(5) Remove the calipers and without touching the zero button set them to minus 1.96mm. THEN RE-ZERO THE CALIPERS AT THIS LENGTH The wire cutters are now used cut off the excess thread leaving a small amount to be filed to the exact length.

Please edit this into the original post if possible Mark.

 

Your wish is my command :)

Link to comment
Share on other sites
  • 2 months later...
  • 4 weeks later...
Geo Distinguished Member

Geo

Posted
  • Author
Posted (edited)

FOR SCREW DOWN CROWNS.

(A) Screw down the crown tightly onto the case without the stem and measure the distance between the bottom of the crown and the case.

(B ) Screw the new stem tightly into the crown, then insert into the watch until it engages and locks into the movement.

(C ) Press the crown down firmly as far as it will go and hold it there.

(D) Using the vernier callipers, measure the distance between the bottom of the crown and the case.

(E) Subtract the size determined in (D) from the size measured in (A) then subtract a further 0.15mm from this size. This is the amount to shorten the stem by. This should allow the crown to screw full home without compressing the stem too tightly between the movement and the inside of the crown.

(F) Cut the stem leaving it slightly longer than the size determined in (E), and dress down to size using the diamond lap and vernier callipers as described in the original post.

(G) Screw the crown onto the shortened stem and check fit and function, before using a tiny spot of Loctite to secure.

This is now added to original post by Geo.

Edited by Geo
  • Like 2
Link to comment
Share on other sites
  • 1 month later...
  • 10 months later...
bobm12 Distinguished Member

bobm12

Posted
Posted

Hi Sendikumar,

 

The screw down crown has a spring between the stem and the crown (it is part of the crown ensemble) that creates a certain tension when properly screwed into the case tube. The spring tension translates into a shorter stem -- since the spring supplies the rest of the length -- and in the end it "takes back" that length to seal the watch...this is normally used in diving watches. Did I confuse you more? I'm not very good at explaining!

 

Cheers,

 

Bob

Link to comment
Share on other sites
 Share
Go to topic listing


  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • VWatchie
      Epilame / Fixodrop

      By VWatchie · Posted

      Yes and no. I use Moebius 9501 synthetic grease and it is significantly runnier than the Moebius 9504 synthetic grease (and I assume Molykote DX) that I previously used. I haven't seen 9504 spread and it is in my opinion the best grease money can buy. However, my current method of cleaning doesn't remove it from the parts, so that's why I have decided to use the 9501 instead. I believe I read somewhere that Molykote DX too is difficult to clean off. Thinking about it, I'm pretty sure my 9501 grease which expired in June 2022 is runnier now than it was when it was new, but whether new or old it always needs to be stirred before use. So, that's why I treat the parts of the keyless works, cannon pinion, etc. with epilame. That was very thoughtful of you and something that had completely passed me by. Not sure what the epilame will do when it wears off in a non-oiled hole. Anyone?
    • watchweasol
      Seiko 6601 Tech Sheet?

      By watchweasol · Posted

      Hi not found one either yet,  close relative is the 436 and 4361 according to ranff.db.   It gives quire a lot of detail but not as good as the old site.      RANFF.DB.
    • nevenbekriev
      Rolex 2235 escape wheel jewel setting replacement

      By nevenbekriev · Posted

      No problem to replace the setting with the staking set. Press the new setting from inside, use flat face punch with hole. The punch must be wider than the setting, the hole to be as not to press at the stone, but only on the bush. Press by hand until the setting gets flush with the plate surface, so the punch must rest on it.
    • nevenbekriev
      Quarter repeater mainspring thickness

      By nevenbekriev · Posted

      Yes, the arbor usually makes about 3 to 3.5 turns. But usually spring takes 2/3 to 3/4 of the free space in barrel, not 1/2, so take it for the calcullations. This way the change in torque is smaller. I have a picture for You, this one is little older, but no mater
    • noirrac1j
      Rolex 2235 escape wheel jewel setting replacement

      By noirrac1j · Posted

      I overhauled a ladies Rolex and noticed erratic performance so I stripped in down again and did fault finding. This is what I saw. The lower jewel (the one in the plate) is cracked and the hole is too big. Before discovering this, I stripped down and re-cleaned the main-plate (and parts) by hand with a fine natural fiber brush. I somehow missed the fault the first time and cannot understand how it was still running. Perhaps re-cleaning it dislodged some pieces of the jewel widening the hole? I don't know. Now I need to replace the jewel but don't have a Seitz tool. The Rolex part is 2130-0913 and the top and bottom are the same. The part comes complete in brass setting with KIF elastor spring and cap jewel. Note: I have never replaced a jewel. I do have a good vintage stacking set that I've used quite a bit.  Can I replace using a stacking set? Any suggestions would be greatly appreciated.  
×
×
  • Create New...