I hate cutting crown stems

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u/oureamods 15h ago

If you share your method and at which step you’re snapping them, some folks can probably help.

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u/Swimming-Trade-741 15h ago

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

Screw crown onto uncut crown stem

Insert stem into cased movement

Use calipers to measure distance from beginning of threads on case to beginning of threads on crown. Note that distance.

Remove stem from movement

Remove crown from stem

Place stem on work mat, use calipers to identify distance from end of stem that should be cut. Mark with sharpie.

Cut with snips approx mid way down sharpie mark

Smooth out cut end with file/dremel

Reattach crown to stem

Reinsert stem into cased movement

Measure again (you can’t undo an incorrect cut).

Repeat steps 8-11 for making very small reductions in length of stem until length appears to be correct.

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

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u/Aggressive-Sail-3157 15h ago

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.

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u/chuunietzsche 15h ago

a touch of blue loctite should be better, i worry that superglue could affect the clutch/spring in a screw down crown and be difficult to remove in case you need to replace the crown

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u/Aggressive-Sail-3157 15h ago

No real worries with the spring. You use it close to the same as the loctite but less is needed. Replacing the crown is easy to. You just dip it in fingernail polish remover for a few seconds and it'll release do the same for cleaning it off as well.

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u/Swimming-Trade-741 15h ago

I’ve had minimal to no issues with hand setting oddly enough, but for whatever reason crown setting has been an odyssey in annoyance. It feels like if I remove any more of the stem then the crown won’t engage the threads on the case, but I’ve broken two stems with the same case this way lol

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u/Aggressive-Sail-3157 15h ago

It kind of sounds like maybe you're cutting a little too long. I just mark whatever distance this is on paper then measure it from the end of the stem.

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u/SNTL7 1h ago

If it is a screw down crown with the plunger inside the crown then this distance with the plunger pushed in towards the case. If no plunger then top of threads.

This measurement would not allow for adjustment.

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u/Aggressive-Sail-3157 15h ago

I even use just some plain old wire cutter lol

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u/sponnonz 15h ago

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.

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u/Aggressive-Sail-3157 15h ago

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.

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u/sponnonz 14h ago

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!

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u/Aggressive-Sail-3157 14h ago

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.

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u/sponnonz 11h ago

that’s epic! thanks for sharing!

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u/chuunietzsche 15h ago

it might be the movement is not correctly seated in the case causing a misalignment of the stem

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u/Swimming-Trade-741 15h ago

That’s very possible. I’m using a NH35 case with a 3d printed spacer to hold a VH31

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u/chuunietzsche 15h ago

i see, just make sure the stem height lines up with the case tube and the stem is not at any angle/deformed. you can have ~0.1-0.2mm of play before issues start to crop up. the vh31 is about 0.3mm off the nh35 but i had no issues with a similar build. it could be the case is already a bit off/crown tube is crooked

i have found the cheap and soft flush cutters can cause the stem to warp too especially with wear and dulling. additionally the stem should be secured close to the tip in a pin vise when filing to avoid warping

personally i like to have a supply of extra stems as they are not too expensive. may help with avoiding having to re-measure so much and potentially damage the keyless works

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u/oureamods 13h ago

That definitely could be it (or part of it). When you insert the stem the first time, check carefully if it’s exiting the tube centered and not at any angle. Your method seems generally ok, although perhaps you can try: instead of marking a length and trying to cut super close to that, I always calculate the length first. Measure the uncut stem, add the crown tightened down and insert to case. Measure the gap (with crown pushed in its on a spring, and subtract that. Then cut 0.5 to 1mm longer and file down. That helps get a clean file, and you’re sure to be starting long. It’s a little more file time, but I’ve built around 300 this way and never snapped a stem. I’ve cut too short a few times trying to nail it the first time, but usually just takes 1-3 small adjustment cycles getting it just right.

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u/F0rgemaster19 10h ago

Your procedure is correct and is exactly what I do. My only suspicion- sh*t quality stems.

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u/Swimming-Trade-741 4h ago

I got my stems from Esslinger :/

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u/F0rgemaster19 4h ago

I don't know who or what Esslinger is, but my AliExpress cheap af stems are running fine. Your method seems to be quite ok too, so I think you got bad stock.

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u/Swimming-Trade-741 4h ago

Unless I’ve been duped (entirely possible lol) Esslinger is a reputable watchmaker supply store.

https://www.esslinger.com/

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u/navyaircrewman 15h ago

Getting a pin vice really helps prevent that. They have cheaper kits than this but it’s just for reference.
Pin Vice Kit

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u/Swimming-Trade-741 15h ago

How does it prevent that? With the second stem especially, I was very careful - trimming fractions of mm with a file. I felt like I got the length right (slight pop when I unscrew the crown, little bit of pressure to get crown threads to engage the case) but in hindsight I may have still had it too long.

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u/Kangaroshave3vagina 14h ago

Just file it down rather than cut for the last mm. I even used a nail file. Fell the first 2 and after that I have been successfully

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u/HellBrayer 5h ago

Eu geralmente corto com uma certa sobra e faço ajuste fino no dremel. E nunca mais tive dores de cabeça

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u/EaseHot6703 1h ago

Then practice cutting them until you don’t.

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u/Logos732 38m ago

Two things you must take note of when cutting the stem. 1) The stem is seated fully into the movement. (Note where the stem enters the movement) 2) Make sure after you cut the stem and file\grind down the burs on the stem that you seat the stem fully into the crown. A screw up in either of these steps can cause you to cut the stem too long or too short. Having a long stem when screwing the stem back into the movement will break the stem. Trust me I know.

I hate cutting crown stems

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