Replacing chronograph pushers, where to start?

[mrkrsl]

I have a lovely Lemania 105, which is working beautifully post-service and is ready to re-case. The trouble is both pusher buttons are missing, and one of the pusher tubes is damaged.

Cousins sell a variety of pushers. The ones in this case are the type which connects the sprung pusher button through the tube with a screw that also acts mechanically on the movement to activate the chronograph works. My best guess is that I need the right diameter threaded "Classical (screw in)" type from Cousins.

https://www.cousinsuk.com/product/classical-screw-in

Can anybody with experience here confirm that or point me elsewhere?

I assume the tubes that are in there can be removed, though I fear they or the case may crumble when I try. They have little serrations on the outside edge. I have a gut-feel fear of removing them for some reason, which is partly why I'm here. I can see from the inside that the holes in the base metal case are threaded, though I don't currently have the removal tools in my kit.

Any advice or direction on this would be most welcome.

[nickelsilver]

Those look like as good an option as you will find. You will really need a special tool to unscrew* the old ones and screw in the new ones. The set in the pic is from Horotec and is great, but probably too much outlay for very occasional use. You can buy just the tips, and hold them in a pinvise or cobble up a handle. The tips are 15 bucks or so.

 

* As yours are severely damaged they might not come out with the tool, especially the one that's already coming apart. As they are trashed anyway, here you can knock  (like with a hammer) a stout cutting broach into the tube and use it to unscrew. They can be really tight, but I've always managed to get them out this way in the end.

 

The new pushers may need some adjustment. I find generic replacements tend to be a little long, which is good, as you can shorten the screw part (the part that pushes on the watch component), but lengthening them is really tricky. Ideally you would do this in a lathe but you can simply file them carefully. Need a screwhead file to put a new slot in then.

 

https://www.cousinsuk.com/product/multi-function-fitting-removing-tools-horotec?code=P19254

 

 

[Kalanag]

I had similar problems with corrector pushers (see here).

I learned that pushers are not specific to caliber but case. There seems to be no standardisation. Therefore it’s hard to find a replacement. I didn‘t.

The pusher tubes are either screwed or pressed in. Pressing a tube out requires to have a matching tool which supports the tube from the inside. Otherwise the tube can collapse or otherwise be deformed.

[mrkrsl]

Many thanks, both, for your replies, and for the tips too. I guess it'll be the hammer/broach approach.

[mrkrsl]

A tiny update, in case anybody looks at this later with a similar question:

I ended up masking the pendant tube and giving the pusher bodies in the case a little bath in WD40. One cup of coffee later, they unscrewed without objection using some needle nosed pliers. I'm not sure why this operation scared me more than disassembling the chronograph, but there you are.

Now I'm hoping the replacements I've ordered are the correct size.