Wednesday, January 28, 2015

Database Updated

I just did a significant database update on the watch serial number site! The site is finally going to start having a lot more data on later Elgin movements, from the 1960s, that previously was not available. It's early yet, and only a small about of new information is there now, and it may be incorrect in places. But it's a start. It will improve quickly.

I don't like to do this major update very frequently because it knocks the thing off line for quite a while, but it's up now.

http://home.elgintime.com/elgintime/SnumLookup

Repairing a Loose Pallet Stone

This 18 size Elgin pocketwatch had a loose pallet stone. This is a common problem in movements that have not been serviced in a long time. Fortunately in this case, the stone is still there, it's just no longer secure.

The pallet stones are held with shellac. To fix this, all I have to do is to set the pallet fork in a pallet warmer and then heat the side with the issue using an alcohol lamp. Then I add a tiny speck of shellac over the back of the stone. It melts from the heat and flows in. Moving the stone a bit to and from while the shellac is liquid assures it will be secure. The shellac firms up almost instantly.

Often this task has to be repeated to get the stone at the right depth for the escapement to function, assembling the watch each time to check it.

Is Your Pocketwatch Hard to Wind?

Something I hear a fair amount is that a watch is hard to wind.

Assuming a pendent-wind watch is in good condition, and has been recently and properly serviced so that nothing is jammed, rubbing, corroded or gummed up with old worn out grease, the amount of effort needed to turn the crown to wind is a direct result of how the watch is designed.

The first factor of course is the strength of the mainspring that is being pulled into tight coils inside the watch.  Particularly on a larger pocketwatch, the force stored up in a wound spring is surprisingly great. To make it easier to coil the spring a typical watch has a pinion and two gears between the crown and the mainspring arbor, which pulls the spring itself. The gear ratios of these turning parts determine how difficult the crown is to turn, and how many turns it takes to fully wind the watch. The designers trade off making the watch very easy to wind, but taking many, many turns, versus taking very few but more difficult turns.

On watches with what we call "exposed wheels", you can see the two principle parts moving when the watch is wound; the main wheel and the ratchet wheel. The gear ratios of these two is the determining factor in how easy or difficult the watch winds.

The movement shown here has exposed wheels. The main wheel is at the bottom. It is directly turned by a pinion, at the bottom, connected to the crown. The main wheel turns the ratchet wheel shown here as the larger of the two taking up the lower left on the movement. The mainspring barrel is directly below the ratchet wheel.

In a watch that otherwise has no problems and is in good working order, with correct lubrication, and the correct mainspring installed, there is no adjustment possible that can make the watch easier to wind.

Monday, January 26, 2015

Beat


The hairspring has to be installed rotated with it's stud in the right place. The hairspring collet is friction fit to the staff, and so it can be turned (with the right tool). The stud, at the outside of the spring's coils, is held fixed by the balance cock when assembled. The stud has to be positioned such that the spring's at-rest position places the roller jewel dead center in the also dead centered fork.

Having set the roller table so that the jewel is 90 degrees to the arms of the balance, the balance wheel arms should be perpendicular to a line through the balance jewels, the pallet fork jewels and the escape wheel jewels.

If this is not right, then the balance wheel, when running, will turn more to one side than the other. A watch like this is said to be "out of beat". It will keep time poorly, and may even stop.

Seating the Roller Table

I like to seat the roller table so that the jewel is 90 degrees to the arms of the wheel. I see them seated all over, just any old way. It doesn't make any functional difference, but I think it's neater and it makes it easier to judge the position of the hairspring, to set the beat.

The balance picture has a one-piece double roller. It's part of a grade 542, 10 size Elgin pocketwatch.

Watch Parts

As replacement parts rapidly become more and more scarce, hardly a week goes by that I don't get an email asking if I could sell such-and-such replacement part. These inquiries come from a variety of folks ranging from people attempting their own watch repair, to experienced watch makers that perhaps don't usually work on antiques.

There's a few reasons I never sell watch parts. One is that it's not like I can just go to a nicely labeled cabinet and pull out the right thing. With antiques, that is almost impossible. For example, this picture shows what I was up against today trying to locate a suitable replacement jewel for a certain pocketwatch.

Another reason I don't want to deal with selling parts is that many folks seeking them don't fully realize that unlike modern products, parts frequently do not just drop into an antique watch. Even original factory made parts (assuming the labels on their packaging are even correct) quite often need to be adjusted to work.


This factory made, Elgin, replacement staff for example badly needed to be polished, tip to tip, before use in a repair.

One other parts complication, especially on very old watches, is that even factory made watches like Elgins, Walthams and Hamiltons have a deep and long history of prior repairs. It is very common that an older watch may contain hand-made replacement parts, which sometimes cause a factory replacement for some other piece to be no longer suitable.

I sometimes get asked why this work is called "watchmaking" and not simply "watch repair," and all this is one of the reasons. To fit a replacement part it is necessary to fully understand the mechanical principles of the watch's design, and be comfortable altering, or fabricating, replacement parts as needed and as suitable to the watch in hand, with respect for its engineering and individual history.

One of the basic rules of this work is that existing components should never be altered to for a replacement part. Every watch has been serviced before. And every watch is different. One has to be ready for anything.