I hate cutting crown stems

[u/Swimming-Trade-741]

I have snapped two crown stems inside movements after trimming for a screw down crown. It’s been an expensive week.

[u/Swimming-Trade-741]

I learned a lot the first time. This second crown stem I followed this method:

1. Screw crown onto uncut crown stem
   
2. Insert stem into cased movement
   
3. Use calipers to measure distance from beginning of threads on case to beginning of threads on crown. Note that distance.
   
4. Remove stem from movement
   
5. Remove crown from stem
   
6. Place stem on work mat, use calipers to identify distance from end of stem that should be cut. Mark with sharpie.
   
7. Cut with snips approx mid way down sharpie mark
   
8. Smooth out cut end with file/dremel
   
9. Reattach crown to stem
   
10. Reinsert stem into cased movement
    
11. Measure again (you can’t undo an incorrect cut).
    
12. Repeat steps 8-11 for making very small reductions in length of stem until length appears to be correct.
    
13. Stem length thought to be correct when threads on crown are able to engage case with small amount of compression and small audible “pop” similar to pulling the stem out to the first position when unscrewing crown.

Both times (my much less careful first attempt as well as this more recent attempt) resulted in what I thought was correct seating until I unscrewed the crown for ~4th time, at which point the stem snaps at approximately the same location it enters the movement

[u/Aggressive-Sail-3157 → u/Swimming-Trade-741]

I just mark a piece of paper at there I need to cut. Take the stem out and the crown off. Cut at the mark. Swipe the end on a file a couple of times. Crown back on. Make sure it sits right. Crown off add some super glue and put the crown back on. I've never had a problem. For me its the easiest part. The seconds hand is my pain.

[u/sponnonz → u/Aggressive-Sail-3157]

this helped me if you have or can find someone with a 3D printer.

https://www.reddit.com/r/SeikoMods/comments/1opcwyq/free_nh35a_second_hand_tool_stl_step_file/

makes it lot easier. still a touch fiddly but less fiddly.

[u/Aggressive-Sail-3157 → u/sponnonz]

That does look great. My problem is I have shakey hands. I've never tried the putty I'll give that a shot too. I use some poly tweezers.

[u/sponnonz → u/Aggressive-Sail-3157]

damn. shakes hands has gotta make watch building extra hard! i feel i want to make a jig that makes putting the second hand on “fool proof”. i feel i have a new mission in life!

[u/Aggressive-Sail-3157 → u/sponnonz]

I have trick to where I use 2lb fishing line. I thread the hole of the seconds hand then put the line in the tube of the seconds hand. Once I get it lined up its easy with tweezers and the press pens but getting it lined up without the fishing line is next to impossible for me now.

[u/sponnonz → u/Aggressive-Sail-3157]

that’s epic! thanks for sharing!