Jump to content

Bent Banking pin - why, and should I straighten it ?


Recommended Posts

I've just stripped an FHF 150 and noticed one of the banking pins is bent. 

Not easy to accidentally bend, so assuming they left the factory straight, why would someone bend the entry pin? 

c.thumb.jpg.f3a044362dc96b499147033d6ec98ba9.jpg

I guess if the entry jewel was pushed in too far, there might not be enough lock, but the jewels look OK.

The first pic is with the fork pushed against the entry banking pin :

a.thumb.jpg.f09777dd724e1fab777d050e27a44f3c.jpg

And this with the fork moved to where I think it would hit a straightened banking pin. 

b.thumb.jpg.dc6791f1c39c019eef957ed957a11dee.jpg

There's not a lot of difference, but it looks like there should be enough lock if I straighten the pin. 

So should I reach for the pliers and straighten ?

 

Link to comment
Share on other sites

1 minute ago, Endeavor said:

I'm just now facing the same problem with an old pocket watch, but before I'm touching the banking pins, I'm going to study EXACTLY what I'm about to do.

That's why I posted !  It seems obvious to straighten it, but I wanted to check in case there's something I'm not considering.

Link to comment
Share on other sites

There seems to be more to consider than I would ever wish for 😉

esc-8.jpg.49a90099e9685875dcc2c2ce69621eac.jpg

The left pin is bend inwards.

The distance of the pallet fork horns to the center-line doesn't seem equal either.

esc-10.jpg.68ae2a53be73c8a82c2461608208f40d.jpg

esc-11.jpg.df366b08889543cb803b953e381877b2.jpg

So, I'm studying now how an escapement exactly works, how to check and how to set-up / correct before touching anything.

 

Edited by Endeavor
Link to comment
Share on other sites

54 minutes ago, mikepilk said:

I've just stripped an FHF 150 and noticed one of the banking pins is bent. 

Not easy to accidentally bend, so assuming they left the factory straight, why would someone bend the entry pin? 

c.thumb.jpg.f3a044362dc96b499147033d6ec98ba9.jpg

I guess if the entry jewel was pushed in too far, there might not be enough lock, but the jewels look OK.

The first pic is with the fork pushed against the entry banking pin :

 

And this with the fork moved to where I think it would hit a straightened banking pin. 

b.thumb.jpg.dc6791f1c39c019eef957ed957a11dee.jpg

There's not a lot of difference, but it looks like there should be enough lock if I straighten the pin. 

So should I reach for the pliers and straighten ?

 

The lock on the first pic looks to be around half the length of a tooth rather than a third. How was it running ? Has it been bent like that to accommodate the impulse for some reason ?

Link to comment
Share on other sites

Hi fellas, I'm pretty sure you've both read this 😂 but it will take some mystery out of things. I know it's a chore without accompanying pics but if you do those checks you won't be bending stuff willy-nilly.

 

Just had a "chronometer" (in name only haha) pocket watch in with both pins bent the same direction, did my checks and the escapement was 👍. Why they were bent I don't know, but I would have spent some time un-doing had I just straightened them.

  • Thanks 3
Link to comment
Share on other sites

25 minutes ago, Endeavor said:

There seems to be more to consider than I would ever wish for 😉

The left pin is bend inwards.

The distance of the pallet fork horns to the center-line doesn't seem equal either.

So, I'm studying now how an escapement exactly works, how to check and how to set-up / correct before touching anything.

 

There looks to be very little lock on the exit pallet jewel - the bent pin could be the cause of that.

Link to comment
Share on other sites

25 minutes ago, Endeavor said:

There seems to be more to consider than I would ever wish for 😉

esc-8.jpg.49a90099e9685875dcc2c2ce69621eac.jpg

The left pin is bend inwards.

The distance of the pallet fork horns to the center-line doesn't seem equal either.

esc-10.jpg.68ae2a53be73c8a82c2461608208f40d.jpg

esc-11.jpg.df366b08889543cb803b953e381877b2.jpg 

So, I'm studying now how an escapement exactly works, how to check and how to set-up / correct before touching anything.

 

The bottom entry pin looks to be set more towards the balance, i would assume this is to allow for different escape tooth contact angles between the entry and exit  jewel 

Link to comment
Share on other sites

13 minutes ago, nickelsilver said:

Hi fellas, I'm pretty sure you've both read this

Yes, today I've set up the escapement (without hairspring) to go (tomorrow) exactly through those motions. BTW, the Omega 861 Mark II (where your response was written for) is still "at rest" until I fully understand what I'm doing.

This pocket watch, even though a precious heirloom, will be a trainer / study for the Omega.

Edited by Endeavor
Link to comment
Share on other sites

11 minutes ago, nickelsilver said:

Hi fellas, I'm pretty sure you've both read this 😂 but it will take some mystery out of things. I know it's a chore without accompanying pics but if you do those checks you won't be bending stuff willy-nilly.

Just had a "chronometer" (in name only haha) pocket watch in with both pins bent the same direction, did my checks and the escapement was 👍. Why they were bent I don't know, but I would have spent some time un-doing had I just straightened them.

Re-read it many times. I'm struggling without pics to visualise the first part - "the function of the pallet jewels relative to the roller jewel and safety roller".

  • at the moment of drop, manipulate the fork to check for freedom, this is "corner clearance". There should be freedom, and the escapement shouldn't unlock
  • move the balance further a few degrees, check the fork freedom again, this is horn clearance to roller jewel face, should be small enough the escapement doesn't unlock
  • continue moving the balance, now you will be checking guard pin clearance. Should be smaller than the horn clearance, and if so it will also be safe

The first statement, what is the freedom to check, the "corner clearance"? At drop I know there must be a gap between fork and pin, but I don't think you mean that?

Ditto points 2 and 3.

 

Link to comment
Share on other sites

34 minutes ago, Neverenoughwatches said:

The bottom entry pin looks to be set more towards the balance, i would assume this is to allow for different escape tooth contact angles between the entry and exit  jewel 

Or maybe not lol

37 minutes ago, mikepilk said:

at the moment of drop

Is this just before the exit  jewel falls of an escape tooth ?

51 minutes ago, Neverenoughwatches said:

Or maybe not lol

Is this just before the exit  jewel falls of an escape tooth ?

Ah the moment it drops on to a tooth

Link to comment
Share on other sites

5 hours ago, nickelsilver said:

you won't be bending stuff willy-nilly.

No that's definitely a bad attitude. Especially with American pocket watches the banking pins are movable and you should definitely move them leave them in some random place because you can what would be the consequences?

1 hour ago, dadistic said:

Here's a copy of a Wostep handout regarding the escapement. It doesn't use the exact same terminology as @nickelsilver's steps, but I believe it covers the same territory.

Just to be technically correct that's not exactly a wostep handout. If you look carefully at the title which I think I changed after I downloaded it it's a combination of wostep and North Seattle community college As that's Where I down off their website. Which is why it's kind of a mixed up mess of things. But still it's good even if it is kind of a mess

Then there's the problem with escapement terminology and time and wherever you're located or and a combination of all of us. If you look at various handouts on the escapement and I'll add in a couple more for you they have differing terminologies and they'll get obsessed with certain terminologies and stuff. The terminology becomes kinda Of amusing like so many things in watch repair there can be actually multiple names for the same part just depending upon where and when. But as you like handouts let's attach a few more.

6 hours ago, mikepilk said:

why would someone bend the entry pin?

I usually think of the banking pins is there for Horn clearance only. But other people think of them as solutions to potential problems that they perceive they have or have not. Which is why typically on American pocket watches with movable banking pins they been moved.

 

Then related to these so-called wostep handout is this lecture. Yes a perfect example of what happens when you film a lecture given at AWCI convention the audio sucks. But it's an extremely good lecture he's a very good teacher is well worth your time and effort to try to make it through it.

 

 

Elgin watch company Escapement Terminology.PDF Escapement Detached Lever Escapement.PDF Escapement Elgin setting up the escapement.PDF

  • Like 1
  • Thanks 4
Link to comment
Share on other sites

12 hours ago, dadistic said:

Here's a copy of a Wostep handout regarding the escapement. It doesn't use the exact same terminology as @nickelsilver's steps, but I believe it covers the same territory. 

Escapement handout wostep nscc.pdf 1.86 MB · 9 downloads

Thanks for posting - a very useful document which contains the pictures needed to explain @nickelsilver's instructions.

Just what I needed 😃

  • Like 1
Link to comment
Share on other sites

11 minutes ago, Endeavor said:

All very Interesting stuff, isn't it ?

It is. I'm just taking it all in. I've got a good idea what to check now. But what's worrying me, is that even working under a microscope, how do you see horn and guard pin clearances 🥴. It's nearly impossible on most movements to get a clear view. Or do you just do it by how far you can move the pallet fork with the balance held in the correct position?

image.png.c29b74eb139be7b629b1078a8e39493c.png

Link to comment
Share on other sites

4 minutes ago, mikepilk said:

It's nearly impossible on most movements to get a clear view. Or do you just do it by how far you can move the pallet fork with the balance held in the correct position?

For the most part it's hard to see this. Sometimes with a pocket watch and no hairspring you can see it. All you really need to see is the fork look at how much the fork moves in relationship to anything else you can see.

  • Like 2
Link to comment
Share on other sites

I'm still experimenting what would work and what not. Also on a pocket watch the parts are much bigger and I'm currently working without the hairspring. But one of my attempts is to transfer the position of the impulse jewel to the top of the balance wheel rim. I made a dot with a black marker on the top of the balance rim and, to the best of my abilities, transferred the center-line pivot/jewel to the rim. Made a small score in the ink ..... at least one has an idea where the impulse jewel is ..... whether it works needs to be seen 🤔

S20221201_001.jpg.e9e0f6ff7a2d87462b757c9baaa4d182.jpg

Edited by Endeavor
  • Like 1
Link to comment
Share on other sites

3 hours ago, mikepilk said:

It is. I'm just taking it all in. I've got a good idea what to check now. But what's worrying me, is that even working under a microscope, how do you see horn and guard pin clearances 🥴. It's nearly impossible on most movements to get a clear view. Or do you just do it by how far you can move the pallet fork with the balance held in the correct position?

image.png.c29b74eb139be7b629b1078a8e39493c.png

Yes, like John said, you check it against whatever other visual reference you can, but since you are really checking the security of the lock at the same time, the pallet stone is the visual reference.

Link to comment
Share on other sites

7 hours ago, clockboy said:

I would leave at first because it has been intentionally bent my a repairer.. Probably to give a deeper lock or an attempt to give a better beat error. 

Unlikely but it might left the factory that way. Always worth doing a escapement check just to see if there is a problem.

Then I've often seen people talk about moving the banking pins to increase or decrease lock but as shown from the image it also screws up the horn clearance. Which is why you should adjust for the horn clearance and then move the jewels not the banking pins.

Then as were discussing moving banking pins the Swiss actually make a tool for this.

banking pins moving consequence.JPG

banking pin tool amusement.JPG

  • Like 2
Link to comment
Share on other sites

  • 2 weeks later...

Just got the movement running. It's taken a while as I had to fit a new staff, and find a new top balance jewel.

It looks to have had a hard working life  (I had to close the barrel arbor hole, and centre wheel hole), so I wasn't expecting much in the way of amplitude. It fired up with 305°. Lubricating the pallets, I get re-banking with full wind.  Strange, as I've fitted the correct mainspring.

I did the escapement checks as listed by @nickelsilver, and all looked OK - apart from the lock on the side with the bent pin being too deep. 

Could the pin have been bent to try to prevent re-banking?

Link to comment
Share on other sites

52 minutes ago, mikepilk said:

Could the pin have been bent to try to prevent re-banking?

It could be. Maybe this one just had the perfect combination of wheels and pinions that matched up better than average, and rather than fit a weaker spring at the factory they bent the pin?

 

What spring do you have in there? GR lists 1.80x0.10x320 for that caliber.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share



×
×
  • Create New...