Can't use NOS 0.18mm seconds hands - Do I need a pivot smoother broach?

[kaplan]

I've stocked quite a bit of 0.18mm seconds hands from a NOS parts dealer, have experience pressing hands, yet I can't press any of the 0.18mm hands I got from this seller. Looking back I've only pressed used seconds hands, so maybe I don't know the process for pressing a new seconds hand

My theories are:
1) I need pivot broaches to smooth them first before using
2) Maybe these are 0.15mm

I'm currently looking at Bergeon 1896-H, but it doesn't specify the exact sizes

Actually took this macro shot, and I think these aren't 0.18mm

 

[JimInOz]

If the pipe is thick enough you can broach to size.
Only do a minute pass each time and test fit as you go.
You'll need a steady hand as the smaller broaches are extremely fine.
I have 1896-G which are cutting broaches ∅ 0.30 - 0.05 mm
I think the 1896-H are smoothing broaches in the same sizes.

 

[kaplan]

Thank you for the suggestion

@noless also suggested the cutting instead of smoothing

If there's no objection I'll order the 1896-G tonight

I wonder if the Bergeon 2676 holder is a must for the job or I can get around it by stabilising the hand on a plate with a hole and some protective film / masking tape

 

[watchyouwant]

I use these. Handheld. Easy to use. I have that Hand holder as well, but don't use it here. These are found from time to time on the Bay for small money. Beware, take your time with that kind of work. Max. one turn of the broach without upward pressure can make the difference between a tight fit and too loose....

 

[kaplan]

Thanks for the suggestion @watchyouwant - these are available from the shop that sends to me as well

When it says 0.20 - does it mean it tapers to 0.20 and starts from something like 0.10? For 0.18 which one do you think I need to b using

(Let me also drop the keyword Bergeon 3008 here too so it helps others in the future as well)

 

[JimInOz]

Use some old hands to get the feel of the broaches before you work on the new ones.
The smoothing broaches have a helical twist (almost impossible to see) and if you screw the broach in too much clockwise it tends to jam.
Rotating the broach anti-clockwise still smooths the bore of the pipe effectively and lessens the risk of jamming and twisting the pipe or the hand itself.

 

[Archer]

You don't need the hand holder - I have one and really never use it. Just go very slow with the cutting broach, and check the fit often.

BTW it's not unusual that new hands need fitting like this.

 

[kaplan]

Indeed, thanks for all the feedback and the suggestions

As I've learned from the seller, this was the reason why Omega switched to pivoted seconds hands later on, they need relatively less fitting and it's less risky to broach them as the seller told

I'm really obsessed with the flat look of old stamped seconds hands though, so even if I have 50% success rate, it will be worth it

As a bit of an amateur suggestion to other amateurs among us, I'll start fitting and calibrating hands without a dial on on a test movement from now on, later on with a test dial, and finally on the actual dial. My biggest fear is damaging a dial and lately issues with hands really affected me on a personal level. As another thing to watch out, the hours hand pivots are long on default and shortened by watchmakers as well, some are shorter than they need to be and can even press onto dials. Did this once on a test watch and it was nightmare material

 

[kaplan]

Thanks for all the suggestions by the way, this new skill unlocked a new world for me

Because of the nature of the operation and the geometry of the broach, going from 0.05 to 0.30 - the resulting seconds hand also has a natural friction stop, so it's very easy to attach securely

I was expecting the seconds hands to start with 0.15, but it actually started somewhere around 0.08 - so all this time looking for certain style and size hands at 0.18 - I could've just bought a 0.16 one in correct style and just bore it a bit, this was the best outcome

 

[watchyouwant]

kaplan

Thanks for all the suggestions by the way, this new skill unlocked a new world for me

Because of the nature of the operation and the geometry of the broach, going from 0.05 to 0.30 - the resulting seconds hand also has a natural friction stop, so it's very easy to attach securely

I was expecting the seconds hands to start with 0.15, but it actually started somewhere around 0.08 - so all this time looking for certain style and size hands at 0.18 - I could've just bought a 0.16 one in correct style and just bore it a bit, this was the best outcome

It's good to know you have them. Eventually you will need others if you dive deeper into the matter....