balance

[gary17]

hey

I just a bit confused been reading on this forum about techniques refitting your balance cock after clean. I've read a few ideas. but all state when the pivot shaft of the balance are lined up top and bottom before you even tighten the cock down it will beat (vibrate,move) even if you have not wound the watch up. So my problem is i have just released the click to remove the power in the mainspring and my balance ain't beating. WHY?

If i remove it and clean it will it start and if the answer to that is yes. HOW?

I suppose i want to no the difference. Please tell me its not PHYSICS.

thanks

gary

 

[watchweasol]

The balance needs power to vibrate, with the balance in place and a couple of turns on the spring if all is well the balance will take off. With no power you can manually vibrate the balance with an artists fine brush by sweeping the rim, at which point it should vibrate for some time on its own and eventually stop as the power diminishes. Its freedom in both cases indicates all is well, before tightening the screw down manually move the movement holder to oscillate the balance and carefully tighten the screw  watching the balance movement if it stops back off the screw and recheck the seating of the staff. If it still vibrates and the screw it tight all is well. The operation takes care and a delicate touch. 

[AndyHull]

With the balance correctly seated in the bottom jewel , bushing or pivot hole (the one in the main plate typically), and assuming the bottom pivot pin on the balance is not damaged, the pivot hole is clean and clear of debris, and any associated jewels are undamaged, the lower balance pivot pin should drop in to the hole in the jewel or bushing.

The fit is such that it will be able to sit in the hole and rotate freely, with minimal friction.

This will allow the balance to swing with little effort (a puff from an air duster or blower will set it rotating).

If this is not the case, then something is restricting its motion.

The suspects being, a damaged, bent or missing pivot, a damaged, cracked or dirty jewel or bushing, a jammed or damaged pallet fork,  the balance is inserted in the wrong position and caught on the fork, or some other debris or damage, or possibly a damaged hairspring is restricting movement. 

If the top balance bridge (or balance cock) jewel or bushing is then aligned correctly on to the top pivot pin, and the bridge allowed to drop in to place, the balance should still be able to move just as freely, since the top pivot should be similarly experiencing minimal friction.

If this is not the case, then as per the bottom jewel, suspect a damaged, bent or missing pivot, damaged jewel or bushing, or dirt or debris in the top pivot hole, or a misaligned or damaged bridge or balance cock component.

This free movement should be  the case even without screwing down the top balance bridge, assuming it is correctly aligned.

If screwing down the balance causes the free movement to stop, then you may have dirt or damage in the jewels, a bent or damaged balance cock, a balance cock that was originally lifted by a shim, that you have failed to replace correctly, or an incorrect component, for example the wrong balance staff is fitted.

With the balance bridge screwed down, the mechanism should be inverted, and the balance should continue to swing freely.

If not, suspect the top pivot pin is damaged, worn or missing, or a damaged balance bridge jewel etc. or even that the lower pivot pin is worn to the point where it has dropped out of the bottom jewel. 

I'm not sure if this clarifies the situation or not, but feel free to ask any further questions.

EDIT: The short answer to your question is YES, if everything is cleaned and clear of debris and correctly aligned, then the balance WILL move freely and easily, if not... see the answer above.

EDIT2: The balance will beat, but the watch will not run, and the beat will diminish, as there is no power except that which you have imparted with a brush or air. This is because the balance is designed to oscillate on the pivots, at a rate determined by the hairspring, but it only needs the power of the mainspring to SUSTAIN that oscillation. In other words it should oscillate with a relatively rapidly diminishing amplitude (it will typically beat for a few seconds to a few tens of seconds) when the spring is not wound, but will oscillate, and the palette fork and gear chain should run, and it will oscillate with a sustained amplitude if there is power being delivered by the mainspring.

Edited August 16, 2019 by AndyHull

[gary17]

cheers weasol and andy.

Finally 10 weeks and 11 watches later i have finally removed and refitted the balance cock. And it works. Small steps i know. but means a lot to me. 

thanks everyone who has answered my some times simple questions.

cheers

gary

Edited August 16, 2019 by gary17

[watchweasol]

Well done Gary, It took small steps to get to the moon