I screw crown in, NH38 stops after an hour

[Nickpan]

I built a watch, goes ok, but I suspect I may have cut the stem too short.  Watch continues untill I screw crown in, then it seems to stop after a couple of hours.  Is that a symptom of the stem pushed in too far?

Embarrassing!  I'm going to run it without screwing the crown in, we'll see if it works fine...

[AndyGSi]

If the stem is the wrong length I'd expect it to have an immediate effect.

Is the crown spring loaded?

[Nickpan]

yes, once I'd fitted it, I found a video that suggested a different (and more logical way) to how I'd done it.  It's been going fine for 5 hours with the crown non-screwed - yesterday I couldn't work out what was affecting it, as it all seemed so random!  I even assumed it only worked with the back slightly loose at one point, but now realise I must have then gone on to screw the crown in...

Time to refit a stem!

[AndyGSi]

49 minutes ago, Nickpan said:

yes, once I'd fitted it, I found a video that suggested a different (and more logical way) to how I'd done it.  It's been going fine for 5 hours with the crown non-screwed - yesterday I couldn't work out what was affecting it, as it all seemed so random!  I even assumed it only worked with the back slightly loose at one point, but now realise I must have then gone on to screw the crown in...

Time to refit a stem!

Is the stem parallel with the movement as I'd expect this to cause problems when screwed down rather then it being too short.

[Nickpan]

next time it stops prematurely, I'll check that out.  Still running at the moment, albeit with a non screwed down crown. 

Actually, that might be the case with my horrendous Diesel watch, as angled pressure on the crown starts it briefly...

Edited March 3 by Nickpan

[Nickpan]

So, it might be my stem... I have a selection of 5, I chose the one pretty damn similar to the stem that came with the movement, but there is a fraction of a difference!  It may well be an instant stoppage once I wound the crown in (as Andy suggested) but I didn't realise that, amongst winding and screwing the back on, I didn't quite suss which action stopped the ticking (and I'm loathe to recreate the problem, in case I do harm). The stem on the left came with the movement but only seems to be a 'place holder', ie, I can't take the blue plastic crown off and use it - is that always the case?  Was hoping that as the movement came with a stem, I'd be alright - but no sign of a stem with a thread, just the shipping one with plastic crown

WAHOO!  Just went through my bin, found the proper stem.  This is such a learning curve

Edited March 4 by Nickpan

[AndyGSi]

Stems need to be exact, close isn't good enough.

[Nickpan]

4th March:  I may have cut the correct stem a little short, the dremel took more off than I was expecting, and I had the same issues, initially worked for a while, then just limps along with constant attention.   Maybe once screwed in, the short stem is pulling against the hacking function, so I ordered more stems.

 

got 5 stems last night, was a bit more careful with the dremel this time!  I left it a fraction too long, let the watch run with crown in position 0 (didn't want to screw the crown in tight with a long stem), It worked for 14 hours (on my wrist), then stopped.   I'm confidant I have a bit of stem length to play with.  Frustrated that the wrong stem, then a short one, and then a long one all have the same non-working symptoms.  I haven't loctited the crown on, so I can trim it... but....

 Is there something I don't know about NH3x movements - do they need winding much, bearing in mind they self wind?  I've always given more than a dozen winds when putting an auto on. 

Edited March 11 by Nickpan

[AndyGSi]

Going back to the start.

Where did you get it from and was it new?

Have you done anything with the movement apart from fitting it?

is it the correct case for the movement?

 

[Nickpan]

Hi Andy, Aliexpress, made sure the case fitted an NH38.  Couldn't get it going last night, and the moment I loosened the back, off she went, ticking like a mo'fo'.  Look at the attached pic, the dial doesn't quite butt up against the chapter ring.  Would that make the difference as to whether the case stops something moving?  It's my only guess.

Actually, I have another guess...the rotor rattles, can actually make it tink-tink-tink by rocking it at the sides, and it doesn't seem to move as fluidly as it should, makes the scratching noise as it swings

Edited March 12 by Nickpan

[watchweasol]

Hi. A too long stem when screwed in will cause undue pressure on the motion work and besides stopping the movement may also cause other as yet undisclosed damage .  The auto rotor should be smooth in operation no extraneous noises, any grating  is either the bearing post, bearing or it’s catching the plate look for scuff marks and check its parallel 

[AndyGSi]

1 hour ago, Nickpan said:

Look at the attached pic, the dial doesn't quite butt up against the chapter ring.

If the dial doesn't meet the chapter ring yet the stem still aligns with the hole then it's not an NH38 case.

As @watchweasol said the rotor should be smooth with no rattle.

Edited March 12 by AndyGSi

[watchweasol]

Hi. TM. COPY OF THE NH35 manual in case it’s of some use to you.

6810_Seiko NH3 Series Part Sheet.pdf

[SwissSeiko]

Im going to to agree with Andy, the case is incorrect, and when you screw the crown in, it places too much force on the stem, causing it to spring to the side a bit, and then placing pressure on the motion works.

[Nickpan]

plopped it all out and back in again, seems to be no noticeable gap twixt chapter ring and dial, screwed it all back together again (but not the crown fully in) and it has been running for an hour, scratchy rotor an' all.  I have an envelope with the returns label on, all ready for the movement if it stops again!

[AndyGSi]

Can you post some photos and details of the case you got.

What movement ring are you using?

[SwissSeiko]

18 hours ago, Nickpan said:

plopped it all out and back in again, seems to be no noticeable gap twixt chapter ring and dial, screwed it all back together again (but not the crown fully in) and it has been running for an hour, scratchy rotor an' all.  I have an envelope with the returns label on, all ready for the movement if it stops again!

I'm struggling to understand why you keep testing it with the crown not screwed in? I think it has been established that the stem/crown are the issue, unless I glossed over this thread to quickly.

[Nickpan]

I've yet to trim the final 1mm off, once I know the bugger will keep going, I will cross the 't's and dot the lower case 'j's.  It seems now that the issue was I needed to shove the movement into the case a bit harder.

Since re-seating the movement yesterday, it's run for 21hours (so far) with stem in, and back cover tightened, so I shall trim and loctite this evening

Edited March 13 by Nickpan

[AndyGSi]

Before you loctite the stem can you post a photo showing how it sits in the tube.

[Nickpan]

[AndyGSi]

So the stem does look central which was one of my concerns.

[Nickpan]

I've come back to this watch, I swapped a new NH38a in.  Fully charged, it ran for 6 hours, then NO amount of shaking would start it, and I chose to not wind it because it should be charged, - then I undid the back case a quarter turn, it started immediately, it's been running for an hour now.  This seems to confirm it's a case issue, not sure what to do now

 

[AndyGSi]

So back to an earlier question, what's the case and what spacer are you using?

[Nickpan]

by spacer, do you mean the grey ring around the movement?

odd that it'll run for 6 hours then stop.  I'm confidant the hands aren't fouling the crystal.  Its been running for 2 hours now, just laid on the table, so I know it was nicely charged, but would not restart until case back loosened a quarter turn

[AndyGSi]

So everything does appear to match up.

Is the dial now seated against the spacer.

Can you post a photo of the movement in the case and one of the inside of the back.