Escapement pinion and wheel assembly

[Nucejoe]

How are escapement wheels and pinion assembled? 

Would instaling the pinion onto the escape wheel on staking set, suffice?      Or the joint should also be shellaced?  

I used to just glue the joint, but do expect some sort of corrossive effect from the glue.

Thanks in advance.

[praezis]

Hi,

wheels are rivetted onto the pinion. 

1 hour ago, Nucejoe said:

Would instaling the pinion onto the escape wheel on staking set, suffice?   

Yes, if it is a new, never before used pinion.
Honestly, I am astonished on this question by you.

Frank

[Nucejoe]

1 hour ago, praezis said:

Hi,

wheels are rivetted onto the pinion. 

Yes, if it is a new, never before used pinion.
Honestly, I am astonished on this question by you.

Frank

Thanks Frank, I guess it is back to gluing for me. This bunch I got are all used.

[jdm]

I have never heard or seen the recommendation of glueing wheels, pinions, etc with shellac or anything else. These should always be friction fit. 

[nickelsilver]

From experience escape wheels are friction fitted, usually onto a turned portion of the pinion leaves. The pinion is so small it's hard to form a rivet without introducing other issues; perhaps some makers 'peened' the leaves where they extend past the wheel. The forces are so light there friction works fine.

Balance staffs get rivetted very securely as they have to hold up to the installation and possible manipulation of the hairspring collet and roller table without shifting, not to mention truing of the balance.

Then of course train wheels need to be very secure, particularly the center wheel.

[Nucejoe]

14 minutes ago, jdm said:

I have never heard or seen the recommendation of glueing wheels, pinions, etc with shellac or anything else. These should always be friction fit. 

 I am seeking to improve on my work. I know gluing is bad practice, have seen evidence of corrosion from old glue on vinatge pieces.

The pinion at hand is so tiny, I can imagine friction fitting,   But rivetting???  Perhaps Frank had image of big pinion in mind.

Thanks jdm.          Regards joe.

[Nucejoe]

34 minutes ago, nickelsilver said:

From experience escape wheels are friction fitted, usually onto a turned portion of the pinion leaves. The pinion is so small it's hard to form a rivet without introducing other issues; perhaps some makers 'peened' the leaves where they extend past the wheel. The forces are so light there friction works fine.

Balance staffs get rivetted very securely as they have to hold up to the installation and possible manipulation of the hairspring collet and roller table without shifting, not to mention truing of the balance.

Then of course train wheels need to be very secure, particularly the center wheel.

Thank you Nickelsilver,  peening on staking set I suppose,  I feel I may damage the stakes, so I guess,  lots of light peens.

Edited September 20, 2019 by Nucejoe
Lots of light tapping

[nickelsilver]

If you damage a punch on an escape pinion it was a bad punch. But yes, lots of light taps, as you can very easily damage the pinion leaves.

[praezis]

NOS escapement wheel and pinion of a wristwatch:
1. Seat of the wheel
2. Tips are peened and bent with a bored punch to rivet the wheel to the pinion.

If you want to re-use a pinion, you can try to flatten back the tips in the lathe, using a pivot file. 

Frank

[jdm]

I understand that the following doesn't apply to  (all ?) Swiss making, but on contemporary Seiko pinions may not be riveted to wheels.
First, no wheel / pinion/ arbor / staff combo is considered to be separable. 

On the left is the magic lever reduction wheel, on the right the escape wheel and here things get interesting (for the maniacal), the vi pinion teeth are really really small, but it seems to me they are not riveted?

Their diameter is (probably) the same as the central section of the pinion, which has been reduced to reduce mass possibly. Of course the wheels seats against a larger section.

Please disregard the dirtiness of the parts pictured, these are just from the scrap bin.

 

Edited September 21, 2019 by jdm