How can i form the holes on hour/minutes hands? (6497-6498)

[JOP]

Does anyone know (or know where can i read about) how to form the pinion holes on hours/minutes hands?

I manage to cut my preferable hands and i can have them with a small hole at the center of their pinion disc. (as reference or very close to what i need)
I can have accuracy in tens (0.Xmm) but it's kind of difficult to have exactly the hole i need in hundreds (0.0X mm).
Also i see that the hands i bought for 6497 /98 have short tubes underneath their holes...

Any kind of help will be appreciated, thanks!

 

[bobandshawn]

Pictures or a drawing might help folks understand a little better...

 

[JOP]

hope that helps

ps; don't mind the design it's just a test

 

[KJ2020]

I bought an inexpensive set of broaching tools for this purpose from esslinger but the times I've needed to do it I ended up using mini drill bits. You can use one the same diameter as the hole and just hold it in a pin vise on a slight angle to sculpt the hole a little bigger then use a larger bit for reshaping properly.

 

[JOP]

I bought an inexpensive set of broaching tools for this purpose from esslinger but the times I've needed to do it I ended up using mini drill bits. You can use one the same diameter as the hole and just hold it in a pin vise on a slight angle to sculpt the hole a little bigger then use a larger bit for reshaping properly.

Thanks,
i see that a size in tens (0.Xmm) is ok for most of my needs. So, a hole with diameter slightly less than the one i need will help me finish it with a proper drill bit.
(ex. laser cut 1.1mm and finish it with 1.2mm drill)

Now i need to know about the short tubes that exist beneath the base plate of hands.
Do you think that i need them? Any reason for their existence? does they give us serviceability? long time life?

I think that since i can drill precisely a disk, i can make a short tube the same and brazing it on disk...

 

[KJ2020]

The tubes are there to raise the hands above the dial, like if for some reason your dial was set a little high from using dial dots, or you had to raise the dial to clear a datewheel overlay. Or also if you needed to clear jewels on the dial, the hands would need to be elevated. If you hour wheel and minute wheel pinions stick out above the dial (most do) and you have no dial obstacles to clear, you can do away with those tubes.

 

[JOP]

The tubes are there to raise the hands above the dial, like if for some reason your dial was set a little high from using dial dots, or you had to raise the dial to clear a datewheel overlay. Or also if you needed to clear jewels on the dial, the hands would need to be elevated. If you hour wheel and minute wheel pinions stick out above the dial (most do) and you have no dial obstacles to clear, you can do away with those tubes.

Great news, thanks!

 

[KJ2020]

It would be a good idea to leave a tiny bit of the tube in case you make the hole too big. You can then pinch the tube to tighten it up and save the hand.