Hamilton Khaki Mechanical / H-50 winding issues

[Kalscheid]

Hey guys. I'm currently having trouble with my handwound Hamilton Khaki Mechanical with the H-50 movement. I usually give it a full wind when I take it out of the box (which if I remember correctly was around 45 winds)
Then I would rewind it in the morning which usually took 12-15 winds. When I feel resistance I stop winding - that's what my watchmaker told me and what I read and hear online all the time.

Well, all of a sudden my watch doesn't reach that point of resistance anymore! I can keep winding as if it was an automatic movement. The watch is still running pretty well at -10s/d

Now, without having opened it I wonder what could be the problem here. I have a hunch that my son might have taken the watch and overwound it while I was not looking but in that case - how is the watch still running?


Thanks in advance for your thoughts. I'm fairly new to the watch repair hobby and I'm not sure I want to try my hands on this watch – I'm still not done butchering my first project…  

[clockboy]

Welcome to the forum, enjoy.. Normally if a hand wound watch does not fully wind ie just keeps winding there is an error with mainspring, either slipping around its winding arbour or the mainspring is broken. 

[watchweasol]

Hi welcome to the forum. One can only reiterate the diagnosis already made by clockboy mainspring problem. But before tearing it to pieces take a little time to read the attached file to acquaint yourself with all the various parts.

TZIllustratedGlossary.pdf

[nevenbekriev]

Hi and welcome.

First of all, check the power reserve. If the watch is runing, this means the spring is attached to the barrel arbor. If there is no end of winding, this probably means that the spring is not attached to the barreland it's outer end is slipping. In such case, the watch will run, but the power reserve will be small - about several hours

[Kalscheid]

Thanks for your feedback guys.

I gave the watch (what I consider to be) a full wind and will check the power reserve. I think the last time I tried, it ran for at least 48 hours so this will take a while. As the watch IS running I think the arbor IS attached to the main spring. I was suspecting that maybe the main spring is slipping inside the barrel much like it would in an automatic watch.