Hairspring Adjustments to Make Watches Run Faster

Written By Alex Hamilton

Alex Hamilton is a watchmaker, collector of fine watches and writer of all topics in the study of Horology.

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What is Watch Adjusting

When watchmakers talk about adjusting a watch they are basically referring to making the watch keep the most accurate time the watch is capable of. Often times I find myself making hairspring adjustments to make a watch run faster or slower because the watch has been mishandled by a previous watchmaker.  Watch movements run at different timing rates depending on the position the watch is in. as one goes through the day the watch will face up, down, to the left, to the right etc. Each of these different positions affect the way the movement keeps time because of the forces of friction and gravity will cause the watch to speed up or slow down as one moves around in everyday life. Good watchmakers can manipulate different components within the movement that affect how those parts interact with one another. This process is done on a timing machine which gives the watchmaker information on how well the watch movement is performing in different positions.

 

Prequisites to adjusting a watch movement

In order for a hairspring to be adjusted to run faster, the watch movement needs to perfectly clean, properly lubricated and have a minimum amplitude of around 270 degrees. Amplitude is a measure of the power transferred thru the train of wheels to the balance wheel. The pivots need to be polished and all the parts of the movement need to be in good order.

These manipulations can be used on any movement no matter the quality, although movements of a lower qualitiy often don’t respond as well.

 

To Speed up the rate in all positions, close the regulator pins. 

This will usually affect pendant rates more than horizontal rates because of the drop in the arch of the balance wheel between horizontal and vertical positions. A hairspring that has equal friction in both horizontal and vertical positions has basically the same arc of motion in all positions, so closing the regulator pin will affect all position the same.

Move both regulator pins away from the hairspring stud.

This has the same affect as moving the regulator arm on the balance cock towards the fast side by shortening the effective  length of the hairspring. If you are making this adjustment the regulator pins should be kept straight up and down as possible. This is often a better solution from just moving the regulator arm to the fast position which can cause the overall isochronism of the movement to be thrown off.

Move both regulator pins away from the balance staff

This adjustment will give all the positions a faster rate because you are again shortening the length of the hairspring. In some cases the hairspring will have more support in certain vertical positions than the other ones which will give them a faster rate than the other vertical positions.

Close the Banking Pin that controls the receiving pallet

Closing the receiving stones banking pin will increase the rate of the watch. This adjustment will work if the hairspring coils off the collet from the right to left. With a maximum change of 4-5 seconds, this adjustment should be done with extreme caution. Close the banking pin so that the pallet fork is resting on after having given the balance an impulse on the winding side of the hairspring. This adjustment should be so slight as no visible change in the slide in the pallet stone can be seen. This adjustment works by lessening the resistance to the Entry Pallet Stones unlocking on the winding side of the hairspring.

 

Raise the Hairspring Stud

When you move the hairspring stud up it makes the hairspring higher. A higher hairspring will run faster in the pendant position. Make sure not to raise it so much that the hairspring becomes out of flat. The reason a higher hairspring action will speed up the rate in vertical positions is because the closer to the base of the regulator pins the hairspring is working, the more effect on the hairspring the regulator will have.

 

 

Lift up on the Over-coil

With a hairspring needle lift up on the over-coil on the opposite side of the regulator pin opposite the hairspring stud. This should be a slight adjustment, not visible with the naked eye. This adjustment will have the same effect as raising the hair-spring stud by creating a higher action and thus faster hairspring in the vertical position. If the regulator pins a perfectly parallel this adjustment will have no effect on horizontal positions.

All these adjustments or manipulations should be done with care. I prefer to do this type of work under a microscope so that I can see what I’m working on. Remember that I have been talking about speeding up rates but all these adjustments can be done in reverse if you need to slow rates down.

 

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