Noob help - identifying movement

[catchthecat]

Hi guys. Not sure what it is. It’s a chrono. An old 7750?

Thanks in advance.

 

[catchthecat]

Well. Spell check doesn’t like the word noob

 

[ward1991]

It's not noon anymore. So I can't help.


It's a 7750

Gen or Asian? A good picture of the balance will tell for sure. But rotor bearing says Asian methinks.

Also 52 posts in 20 years is hardcore! Lol

 

[catchthecat]

It's not noon anymore. So I can't help.


It's a 7750

Gen or Asian? A good picture of the balance will tell for sure. But rotor bearing says Asian methinks.

Also 52 posts in 20 years is hardcore! Lol

Hey thanks. I thought it might be but couldn’t remember. The stem snapped at the crown and want to see if I can do my own replacement. My watch knowledge is rusty.

But yeah. I’m a good listener though! a man of few words

When you look up the definition of lurking in the dictionary you’ll see my picture.

 

[catchthecat]

Can’t find the darn edit button to add to my previous comment, but you are correct. it’s an Asian movement.

 

[ward1991]

Hey thanks. I thought it might be but couldn’t remember. The stem snapped at the crown and want to see if I can do my own replacement. My watch knowledge is rusty.

But yeah. I’m a good listener though! a man of few words

When you look up the definition of lurking in the dictionary you’ll see my picture.

You should be able to replace the stem easily.

Is there a piece of stem stuck flush at the crown? Can you grab enough with needle nose pliers or a pin vise to remove the bit of stem from the crown?

If not, you will want to grab some "alum powder" off Amazon, mix it with water and put the whole crown inside, in 2-5 days it will dissolve the stem peice left inside the crown without hurting the rest of the crown.

Once it's gone, take your new stem and start testing how long it needs to be. I like to just screw it into crown and install it in the movement, cut a little, then repeat. Don't cut too much off at any given time, then when you have made your final cut lightly sand the end and place some loctite blue on the threads and screw it in, insert the stem into the movement.

 

[catchthecat]

You should be able to replace the stem easily.

Is there a piece of stem stuck flush at the crown? Can you grab enough with needle nose pliers or a pin vise to remove the bit of stem from the crown?

If not, you will want to grab some "alum powder" off Amazon, mix it with water and put the whole crown inside, in 2-5 days it will dissolve the stem peice left inside the crown without hurting the rest of the crown.

Once it's gone, take your new stem and start testing how long it needs to be. I like to just screw it into crown and install it in the movement, cut a little, then repeat. Don't cut too much off at any given time, then when you have made your final cut lightly sand the end and place some loctite blue on the threads and screw it in, insert the stem into the movement.

 

[catchthecat]

You should be able to replace the stem easily.

Is there a piece of stem stuck flush at the crown? Can you grab enough with needle nose pliers or a pin vise to remove the bit of stem from the crown?

If not, you will want to grab some "alum powder" off Amazon, mix it with water and put the whole crown inside, in 2-5 days it will dissolve the stem peice left inside the crown without hurting the rest of the crown.

Once it's gone, take your new stem and start testing how long it needs to be. I like to just screw it into crown and install it in the movement, cut a little, then repeat. Don't cut too much off at any given time, then when you have made your final cut lightly sand the end and place some loctite blue on the threads and screw it in, insert the stem into the movement.

Wow! Thanks for the guidance. In fact, there is a tiny piece of the stem in the crown I’ve been struggling with how to get it out to reuse the crown. Was thinking I’d need to source a new crown.

But you’ve piqued my non chemist curiosity as to how or why alum dissolves the piece of stem but doesn’t harm the crown. Assuming it only works on specific metal types and the crown and stem are different?

 

[ward1991]

Wow! Thanks for the guidance. In fact, there is a tiny piece of the stem in the crown I’ve been struggling with how to get it out to reuse the crown. Was thinking I’d need to source a new crown.

But you’ve piqued my non chemist curiosity as to how or why alum dissolves the piece of stem but doesn’t harm the crown. Assuming it only works on specific metal types and the crown and stem are different?

Correct it will eat away slowly at non-ferrous metals.

The process is sped up by keeping the solution warm, but I like to just set it and forget at room temperature for awhile.