Forums Latest Members

Basic Watchmaking tips - checking and adjusting end shake

  1. Archer Omega Qualified Watchmaker Aug 16, 2019

    Posts
    26,343
    Likes
    65,049
    This is another in a series of posts I’ve made to assist both professional and amateur watchmakers. The others can be seen in these threads:

    https://omegaforums.net/threads/basic-watchmaking-tips-cleaning.56365/#post-696021

    https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-1.62310/

    https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-2-the-mainspring-barrel.71246/

    https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-3-the-wheel-train.84482/

    https://omegaforums.net/threads/basic-watchmaking-tips-spotting-wear.81025

    /https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-4-the-escapement.87072/

    https://omegaforums.net/threads/basic-watchmaking-tips-replacing-a-balance-staff.96778/


    So the first thing is to define what end shake is. In non-watchmaking terms, this would be called end play, and it’s the amount that the item moves between the two bearing surfaces that limit it’s axial travel. Since this check is done with the watch movement typically laying flat, it’s a vertical check, so how much the wheel or other part moves up and down between the jewels, bushings, or plates. End shake is important because the wheels need some freedom to move, and if end play is not sufficient you will have binding of the wheel up against the jewels, leading to a loss of power and possibly a watch that doesn’t run. Too much end shake can cause misalignment problems in the wheel train.

    End shake is not the same all the way through the wheel train, and generally speaking the further away you are from the mainspring barrel, the lower the end shake value should be. So the mainspring barrel itself will have some end shake, the center wheel will have a bit less, the third wheel a bit less, and so on down to the escape wheel, which will have the smallest amount of the train wheels. The balance wheel and pallet fork tend to be the smallest overall. It should be part of every watchmaker’s (amateur and professional alike) to check the end shake on the watch, and if you have the means, correct it as necessary.

    So how do we check end shake? It’s not really measured with any sort of tool, and is generally done by eye. When in school we were given some examples that were made up specifically for training, so a platform with a jewel in it, a wheel, and another platform with a jewel on top – these were not complete movements. These had known end shakes that were measured, and we were tested on being able to accurately judge the amount of end shake in these known examples by checking them by eye. Essentially the way to check it is to use at least 10X magnification, look at the pivot in the jewel, move the wheel up and down in the jewel, and see how much it moves.

    Measuring this by eye can be tricky and requires some experience, and the smaller the end shake is the easier it gets, which sounds counterintuitive. For example 1/100ths of a mm end shake is something you feel more than you see. At 2/100ths you can see it move, and it goes up from there. But telling the difference between say 6/100ths and 8/100ths gets more difficult, because they look a lot alike.

    This is a photo of a Cal. 861 Speedmaster that I serviced recently, and when I was inspecting the movement before I took the watch apart, I could see that on the escape wheel the pivot of the wheel wasn’t really sticking out of the jewel at all:

    [​IMG]

    The pivot should be sticking proud of the jewel, so I knew once I have the movement apart and cleaned, I could check this in more detail. Note that checking end shake should be done with a clean movement, because if there’s dirt built up under the jewel or on the wheel, it can give you a false reading and change once that dirt is washed away in the cleaning process. So once everything was clean, I assembled just the escape wheel and it’s bridge on the main plate:

    [​IMG]

    Again you can see that the pivot is not sticking out of the jewel:

    [​IMG]

    So how are these jewels held in place? By friction, so these are called friction fitted jewels. There are other types of jewels that are bezel set and those present a whole host of different issues, so I won’t be covering those here. The hole in the plate or bridge that the jewel goes into is a straight sided hole (parallel) that is slightly undersized for the maximum outside diameter of the jewel. The sides of the jewel are tapered, so it’s a bit like fitting a plug in a hole. For the most part these jewels will be pushed in from the inside of the plate or bridge, so jewels that go into a bridge will be pressed on the from the underside of the bridge, and jewels that are pressed into the main plate will be pressed in from the side of the plate where all the internal parts mount. So the flat side of the jewel is usually the large end, and the concave side will be the small end.

    So I need to move the jewel, and for that there is no better tool than the Horia tool:

    [​IMG]

    I select a pusher that is just a bit smaller than the outside diameter of the jewel, and a stump that has a hole in it that is just a bit bigger than the outside diameter of the jewel. This is important because if you don’t get the sizing right, the jewel could be damaged. Here I have placed the escape wheel bridge in the tool:

    [​IMG]

    Here I am moving the jewel down, and there is a Vernier style scale on the barrel of the tool that indicates the movement in increments of 2/100ths of a mm, and you can easily split and read between the lines for adjustments of 1/100th or less:

    [​IMG]

    Omega calls for the end shake on the escape wheel to be between 2/100ths and 5/100ths of a mm. This one was much larger than that, and in the end I had to move the jewel 6/100ths of a mm. Here is a video showing the end shake before I made the adjustment, and the after:



    So one area on Speedmasters than tends to be an issue from time to time is not only the end shake, but also the alignment of the parts. Every time you make an adjustment, you have to consider what else it might be affecting. Here is the escapement from another 861 Speedmaster I serviced recently:

    [​IMG]

    So the first thing I see is that there is oil in all the wrong places, so whoever serviced this last didn’t do a good job of oiling this escapement. Big blobs of oil are at both sides of where the pallet fork jewel meets the fork, and also on the back side of the escape wheel teeth. But that’s not the real reason I show this particular escapement – if you look closely you will note that the escape wheel tooth seems to be acting very low on the pallet fork jewel. So when I disassembled the movement, I pulled the pallet fork out and pushed it into some pith wood, and took this photo:

    [​IMG]

    First there is far too much oil here, but if you look at where that streak of oil is, it’s all on the left side of the jewel, which is the lower half of the jewel. So after I fully cleaned everything, I assembled the pallet fork and escape wheel on the main plate to check the alignment between the two:

    [​IMG]

    This is difficult to photograph, but I was able to place the movement holder in the microscope and stand it on edge, and look down to there the escape wheel tooth meets the entry pallet jewel. As you can see, the escape wheel tooth is very low on the jewel:

    [​IMG]

    Now the bottom of the escape wheel teeth have a chamfer, so most of the part of the teeth that contact the jewel are in the upper half of the teeth. So this is getting some contact, but not a lot. Also there is a lot of end shake, and this the worst case scenario – with the pallet fork as high as it will go, and the escape wheel as low as it will go. So I set about adjusting the jewels for both the escape wheel and the pallet fork – the pallet fork I mostly just constrained the end shake vertically, as it was a bit too large. The escape wheel I raised the lower jewel quite a lot, and also had to raise the upper jewel a bit. This was the end result, and you can see that the teeth are far more centered than they were before:

    [​IMG]

    It’s unclear how this watch got in the state it was in, so possibly someone damaged a jewel and replaced it, but didn’t make sure it was put back in properly. When I see alignment issues on the escapements in Speedmasters, it’s more common that the escape wheel is too high on the jewel on some Cal. 1861’s, like this one:

    [​IMG]

    After adjusting:

    [​IMG]

    I was seeing enough of these that had to be adjusted that I emailed a contact at Swatch group in the US, who confirmed that they knew that this was an issue on a number of these movements, so it’s always good practice to check the alignment here, and the easiest way to do that is to check where the streak of oil is on the pallet jewels.

    So I use the Horia tool for making these adjustments, but an alternative is to use a Seitz jewelling tool – I have both and prefer the Horia tool by a wide margin, and I use the Horia tool pretty much every day for some task. Another option is that often a good quality staking set will come with jewelling attachments, and my K&D 18R staking set does have them, but I’ve never used it for this purpose.

    So at this point I’ve talked about end shake in the context of jewels and wheels for the most part. But there are other instances where end shake needs to be checked and adjusted that doesn’t involve jewels. One common area is the mainspring barrel, and the barrel arbor end shake. The arbor, like any other rotating shaft in a watch, needs end shake so it can spin freely, and I check that when the barrel is in my barrel closing tool. I use the lid of the tool to lightly hold the barrel, and use my tweezers to check how much the arbor moved up and down:

    [​IMG]

    If the end shake is too little or too great, I check the barrel cover and barrel drum to see which one has a high or low spot. I use a punch from my staking set and just lay it across the part, and look for a gap. Most times the cover or drum will be coned outward from opening the barrel. I then adjust it by bending it in the opposite direction using the plexi stick:

    [​IMG]

    When doing this, it’s important to keep the stick as perpendicular to the part you are bending as possible. If you bend one side of the barrel cover or drum more than the other, it may cause a tight spot even if the arbor appears to have enough end shake.

    Another area where end shake is important is under the dial. The hour wheel is where the hour hand mounts to, and in many cases it is only held in place by the dial. If the hour wheel has too much room to move vertically, it can become disengaged from the minute wheel and move a tooth or two, leading to the hour and minutes hands drifting out of alignment. Here is the dial side of a movement showing the minute wheel at the read arrow:

    [​IMG]

    This shows the dial side with the hour wheel mounted (red arrow), and the large diameter on the hour wheel mates with the small teeth at the center of the minute wheel:

    [​IMG]

    Here the dial washer is added, and it’s s thin foil washer that is bent so that when the dial is installed, it will put some pressure on the hour wheel to help it stay in place. It also provides some drag to help take up the slack in the teeth of the time train:

    [​IMG]

    So after you mount the dial, it’s always a good idea to check how much the hour wheel can be lifted up. Normally this is not a huge problem but I have come across the odd dial than has been bent and there is too much end shake, so I’ve had to bend the dial back using a similar process to how the barrel is adjusted.

    So end shake is an important aspect of watchmaking. As always, if you have any questions, please let me know and I’ll do my best to answer.

    Cheers, Al
     
  2. Eve Aug 16, 2019

    Posts
    1,489
    Likes
    4,886
    I wish i had access to a workshop place with just a fraction of tools that you have :whistling:
    Great post as usual, Thank you!
     
  3. rob#1 Aug 16, 2019

    Posts
    1,932
    Likes
    3,159
    Fascinating. Thanks for your invaluable input.
     
  4. Pahawi Aug 17, 2019

    Posts
    1,150
    Likes
    3,360
    Amazing - thanks Al.
     
  5. Deafboy His Holiness Puer Surdus Aug 18, 2019

    Posts
    2,167
    Likes
    6,115
    Merci Al.