Chronograph hand loose

[AP1875]

The centre sweeping hand has become loose on my watch. It’s a Chinese clone movement and there are no spares available unfortunately.

Where the hand attaches to the post is nice and tight. The problem is with the construction of the hand itself. I’m sure you guys know how these are put together but for anyone that doesn’t know, the hand is made of two parts the post and the part that rotates around the dial.
 

Looks like these two parts are just pressed together. This connection between the two parts has become loose, so when you reset the hand it won’t return to 12 (sometimes a few ticks off, sometimes 1 etc).

Ive tried using super glue and two part epoxy to hold the parts together but it hasn’t been successful.

Does anyone have any suggestions?

[CaptCalvin]

They're staked together. You can repair it by staking it again if all relevant pieces are in good shape

Edited March 19, 2020 by CaptCalvin

[AP1875]

i presume they’re just pushed together.

what is the difference between pushing them together and staking them?

I’m  thinking the bottom pipe part has slightly worn the top part which is making it slip.

[nickelsilver]

Staked means rivetted, and there's a big difference between a rivetted union and press fitted.

[AP1875]

Thanks.

so if these hands were staked (riveted) together and now that part is loose. That indicates to me the part is damaged and the hole is probably worn so too big for the post part (I may be completely wrong here?). If it is damaged/worn is it possible to stake them together again?

Thank you for helping, I’m learning all the time here.

[CaptCalvin]

In a lot of cases re-staking is possible. If you don't have a staking set a crude method with thumbtack I've tried before worked for me:

Fit the tube back into the hole and have it stand upright, and then tap the tip of the thumbtack into the hole. Make sure to start with light taps and check progress under magnification as to ensure you don't split the tube. You just want a bit of expansion of the tube where it fits into the hand. Also make sure to do it on a hard surface so it doesn't absorb any of the impact and have the tube driven into it.

Also consider filing the tip of the thumbtack to put some facets to it. This will make the rivet irregular and stands to have less of a chance of slippage at reset than a perfectly round rivet. Although the one time I tried the thumbtack I didn't bother with this and the subject watch hasn't given me any problems yet.

Edited March 19, 2020 by CaptCalvin

[AP1875]

I do actually have a K&D staking set (I have a bit of an obsession collecting tools), not sure if I have all the correct parts to do this repair though. Unfortunately I  have no idea how to perform this task though. I’ve checked YouTube and can’t find anyone doing this. Would love to give it a go though if you guys have the time to run me through it :-) 

 

here is a video of what is happening 

.

 

[clockboy]

Maybe a tiny touch of loctite might work. If not source a replacement hand.

[AP1875]

I’ve tried super glue and epoxy neither will hold after a few resets. I’ve asked someone in China who can get most parts and they told me the ‘company’ that make these hands will not sell them separately.

[FLwatchguy73]

What model is this movement?

[AP1875]

6 hours ago, CaptCalvin said:

In a lot of cases re-staking is possible. If you don't have a staking set a crude method with thumbtack I've tried before worked for me:

Fit the tube back into the hole and have it stand upright, and then tap the tip of the thumbtack into the hole. Make sure to start with light taps and check progress under magnification as to ensure you don't split the tube. You just want a bit of expansion of the tube where it fits into the hand. Also make sure to do it on a hard surface so it doesn't absorb any of the impact and have the tube driven into it.

Also consider filing the tip of the thumbtack to put some facets to it. This will make the rivet irregular and stands to have less of a chance of slippage at reset than a perfectly round rivet. Although the one time I tried the thumbtack I didn't bother with this and the subject watch hasn't given me any problems yet.

So using the thumbtack method I could keep the hand tight  in the collet (as seen in the video)and knock the tack from the top? This would force the Pipe part of the hand to expand slightly inside, hopefully gripping the hand.

is the method the same with a staking set? Knock into it from the top?

Edited March 19, 2020 by AP1875

[CaptCalvin]

Does the tube have a lip around it to support the hand as in the first picture or just a straight tube with the top turned down to fit into the hand? The straight tube type would be a little more challenging. 

Do you know how to use a staking set? I dont have a staking set on hand at the moment but I would start with the sharper punches and progressively move through blunter and blunter punches until the rivet is nicely rounded and peened over.

[nickelsilver]

A big issue with staking or restaking tubes like this is distortion of the tube itself. I've made up stumps with a hole diameter ever so slightly bigger than the tube, depth ever so slightly less than the length, so I can rerivett the darn thing without bending or otherwise deforming it. They can be a real bear.

[AP1875]

Ok so it looks like the hand in question is the type that’s ‘easier’ to work with

 

only issue now is I don’t really know what the procedure is.

This is the tool I have, it came with a K&D box with quite a few bits. I was told I’d need a staking set at some point so hopefully this works out. Any direction greatly appreciated.

[CaptCalvin]

Reason why these are easier to fix is because they can simply be set into a hole in the staking contraption and not fall through.

1) Find the smallest hole on the platform that the tube will fit in. 

2) Loosen knob behind contraption.

3) Insert centering punch (sharpest pointed).

4) Rotate platform and drive centering punch into selected hole.

5) Tighten knob. This ensures whatever punch you're going to use is aligned with hole.

6) Insert tube into hole and fit hand on the tube.

7) You're going to have to judge for yourself which punches to use here. Start with the sharper punches and work your way towards blunter punches. The idea here is you want to expand the tube so that it grips the hand, and you'll also want the top of the tube to curl outwards and over. Sharper punches are more efficient at the expanding, and blunter punches will do the curling. Don't get aggressive with the sharp punches and go too deep and split the tube.

But really it would be nice if a someone with actual experience chimes in. I haven't yet touched a staking set (poor college kid). This is just a procedure I've thought up in my head with knowledge accumulated through books and internet. Try it if it makes sense to you haha. 

[Hondadoug]

I think in this case a small flat punch is all that is needed to flatten the rolled portion and restore the crimp. Don’t over think this  it is just a very simple basic repair. Make sure your anvil supports the lower flange .

[CaptCalvin]

16 minutes ago, Hondadoug said:

I think in this case a small flat punch is all that is needed to flatten the rolled portion and restore the crimp. Don’t over think this  it is just a very simple basic repair. Make sure your anvil supports the lower flange .

Starting with a flat punch would be smart actually. Chances are that's all you need. And if it doesn't work then you can try the pointed punches. Flat punches are more forgiving so not a lot of harm done as opposed to trying the pointed punches first thing and whacking it a bit too hard.

Edited March 20, 2020 by CaptCalvin

[AP1875]

Ok so I put the hand in the base like this?

 

I will then line up the base with a stake, so a flat stake can sit directly on the hand (I will use some plastic wrap to protect it)

the idea is to use the force from the stake on the top of the hand and hopefully it will cause it to expand gripping the hand.

Did I understand that correctly? I just want to make sure I’m doing this correctly because it looks like I’ll only get one shot at it. Thanks 

[CaptCalvin]

Looks right. Though the plastic I would imagine to be counter productive. You want the punch to be directly in contact with the metal. Plastic will just absorb the impacts until it's smooshed all the way through.

[Hondadoug]

So...... did it work?

[AP1875]

I haven’t tried it yet, I was just giving it a little more time for anyone rose to potentially give me some advice. Think I’ll try it this evening.

[nickelsilver]

CaptCalvin's advice is pretty spot on, only thing I'd add is a little goes a long way regarding how hard you tap, and better to err on the side of too little.

[AP1875]

So start with the sharpest/fine tipped stake and then move to flat?

- tap lightly. I assume there will be a bit of tapping it, removing and fitting and then tapping again.

[nickelsilver]

Even though they hammer into your head in school to never ever use the centering punch for anything but centering, I find it's the best for staking these tubes. I start with that, then the smallest round nose punch, then a flat punch.

[AP1875]

So these are the stakes I received in the set.

Top left seems to be the sharpest, but sill not really fine. If I need to order some better stakes I will. What do you guys think?