Balance wheel settling time

[LittleWatchShop]

In engineering, this test would be like testing the Q of a resonant circuit.

I have removed the pallet fork and starting the balance with a puffer.

Does this look like it is has a long enough settling time?

This is not the original HS that came with this watch, nor is it original balance wheel.  The balance is a NOS for this watch but it is more modern because it lacks adjustable balance screws.  The HS came from a donor.

[nickelsilver]

Should go way longer than that, something is amiss.

[mikepilk]

For a balance wheel like that, my test is (not based on anything but experience) : give it a good blast from the puffer, and there should be good movement ( >180°) after 30 seconds. 

[Jon]

You know if you mix and match balances and hairsprings, you then have to vibrate the hairspring and balance by finding the pinning up point, so the hairspring is able to regulate the movement at whatever beats per hour required.

You may already have done this

[LittleWatchShop]

29 minutes ago, Jon said:

You may already have done this

No I have not, but I understand the issue.  This is a breguet, so that option may not be available in a direct way.

[nickelsilver]

3 hours ago, LittleWatchShop said:

In engineering, this test would be like testing the Q of a resonant circuit.

 

Funny- there is a procedure in the design phase of watch development where the "Q factor" is determined. There is a lot of math involved, but very basically, taking into account the inertia of the balance, its hairspring specs, frequency and some other stuff, they start it vibrating at a given amplitude (300 seems to be the base) and then measure how long it takes to come to rest. I have the formula in one of my books somewhere. The Q of a really good wristwatch might be 200, 600 for a pocket chronometer, higher still for a box chronometer, etc.

 

When vibrating a new spring on the Luthy tool, where the balance is suspended by the spring with one pivot resting on the glass, it's pretty easy to get 60 seconds of run with a start amplitude of 180. What Mike observes with the balance in the watch sounds pretty spot on.

Edited August 29, 2022 by nickelsilver

[Nucejoe]

 End stones might be pushing on pivots, if so  loosening the cock screw until the oscilator runs freely gives you a good feel of what minimum end shake suffices.

[Mark]

Moving to correct sub-forum.

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Why is this happening?

Please don't be offended - from time to time, in an attempt to keep WRT organized, we need to move threads to another area more suited to the subject of that thread. Members can help the forum staff by checking for a suitable sub-forum before posting as this will help to reduce their admin workload.

 

[LittleWatchShop]

Sorry about wrong sub forum.

Anyway, this watch will surely turn me into a real watchmaker, no?  For sure...my fear of messing with hairsprings is totally gone.  Maybe that is bad, because healthy fear can be useful.

The hairspring is rubbing against the bottom of the stud in spite of the fact that it is oscillating in a near perfect planar fashion.  I cannot raise the stud any farther into the cock, so I am pondering filing it down.  To do that, I think the only safe way is to remove it from the HS.  Really don't want to do that, so I am stepping back to ponder this before I make an abrupt move that is irreversible.

Edited August 29, 2022 by LittleWatchShop
farther, not further!!!

[Mark]

2 hours ago, LittleWatchShop said:

Sorry about wrong sub forum

No problem at all

[LittleWatchShop]

Good news.  I have amplitude!!  I decided to file the stud while attached to the cock.  It was easier that way.  I went searching through my dad's files and he must have known I needed it--found a super fine file that worked perfectly.

The watch is running slowly, but I can remove a couple of screws to speed it up.  That is the next step.

BTW, I reverted back to the original balance and the staff that I made.  I feel pretty good about that.