3646 case type - how to remove crown from stem?

[Nick_B]

Upgrading from an A6497 to ETA. All done and successful, but I need to remove the crown from the original stem... and I can't figure out how :idontno:

I assume the tubular section of the crown unscrews from the crown itself, releasing the spring and stem, but maybe it's a reverse thread? I'd much rather know what I am doing before proceeding.

Advice would be much appreciated at this point

 

[Raddave]

its not reverse thread , grip the stem in a pin vice and turn the crown to the left , if its too tight, try a little heat , there might be some threadlocker on it

 

[Nick_B]

Thanks Raddave. Just what I needed to know... :thumbup: Also apologies if this isn't in the right forum...

 

[Raddave]

Thanks Raddave. Just what I needed to know... :thumbup: Also apologies if this isn't in the right forum...

no worries , good luck with all !

 

[Nick_B]

Thanks mate!

It's rock-solid, so for sure there's some Loctite or similar in there. I need to tweezer out the ring seal inside the crown cap and heat the job to free the thread as you advise. Will do it over the weekend - beer-0-clock in UK time so no more work today

 

[capice]

If it doesn't come out, you could use some alum(ammonium aluminum sulfate), the crown will not be damaged

https://mb.nawcc.org/threads/removing-broken-screws-with-alum-bath.94417/

 

[Nick_B]

If it doesn't come out, you could use some alum(ammonium aluminum sulfate), the crown will not be damaged

https://mb.nawcc.org/threads/removin...um-bath.94417/

That's good to know. I had it in the back of my mind that there might be a solvent that could be used as an alternative to direct heating so thanks for the link. I need to sort this out as the crown isn't properly fast on the stem and sometimes rotates freely or becomes disengaged during winding, which is, as they say, suboptimal

 

[Nick_B]

Interestingly, just for any future reference here, the consensus on the thread Capice linked above is that alum will corrode steel, so I'll probably just use direct heating. Also, I don't have any and would need to order some online etc. But there are four perfectly good gas rings on the kitchen hob

Wiki sez:

Alum in the form of potassium aluminium sulphate or ammonium aluminium sulfate in a concentrated bath of hot water is regularly used by jewelers and machinists to dissolve hardened steel drill bits that have broken off in items made of aluminum, copper, brass, gold (any karat) and silver (both sterling and fine). This is because alum does not react chemically to any significant degree with any of these metals, but will corrode steel. When heat is applied to an alum mixture holding a piece of work that has a drill bit stuck in it, if the lost bit is small enough, it can sometimes be dissolved / removed within hours.