Home Forums General Discussion Forum Clock Gears Not Running True

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      I was just watching a burnishing video and noticed that the gear was not running true on the shaft. I’ve watched several of these videos and most, if not all of the gears seem to be running a little off of true. My first inclination would be to straighten such a gear.

      It just dawned on me that this may be intentional. If the gear is a little off, it seems to me that it would distribute the wear on the pinion, thus extending the life of the clock. I guess if the number of teeth on the gear were an integer multiple of the number of teeth on the pinion, it wouldn’t make much of a difference because the gear teeth would hit the same spot on the pinion?

      Has this occurred to anyone else?

      Steve Fox


        Hi Steve,
        the trains are designed to run with the minimum of friction, the tooth form has been designed to run straight. If the wheel is slightly out of true this will cause unwanted friction. You see clocks sometimes with some bent wheels and although they might still run they are not running as efficiently as they could. I wonder if for the sake of the video they have just grabbed and old wheel out of a spares box as you can t get close enough to see properly without getting in the way of the camera so there is more chance of the wheel jumping out. If this is not the case then it makes you wonder if these guys know what they are doing. I would be interested to see one of these videos.


          @SteveFox wrote:

          it seems to me that it would distribute the wear on the pinion, thus extending the life of the clock

          Hey Steve, not sure, the worn pinions I have seen are all worn in a certain spot, some almost cut through. it is interesting though that it is the steel being worn before the brass (at least thats what it looks like), there has been alot of debate about how that happens, like in the case of a hardened burnished steel pallet face having a groove worn into it by the brass escape wheel which still appears to be untouched. To me it doesnt make sense or have I ever read of a particular formula to purposely bend a wheel to help the wear issue. Good job on catching that, I never noticed. have a fantastic day, William

          david pierce

            You were just observing some sloppy machine work. If you watch the Roger Smith video on Youtube you can see the care they take to line up their gear blanks before machining them.


              The dust and oil get embedded in the brass ( bein softer(this then grinds away at the engaging steel be it pinion
              Leaf / lantern trunion or pallet face
              It’s one of the reasons a polished clock movement doesn’t wear as quickly as one that isn’t
              The same is also true of pivot holes which is why smoothing/ burnishing broaches should be used and the holes pegged out very thoroughly . . .

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