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I am working on this alarm clock , which did not run when I got it from ebay. The movement was very dirty and the mainspring was broken. I replaced the springs, cleaned and lubricated the movement. Now it is ticking for about 20-30 seconds and then stops. I noticed that the escapement is out of beat and wondered what would be the best procedure to correct this.
The movement has a two crossed arrows mark which would indicate that it is an old Junghans movement.
Jan
@Arutha wrote:
Hi Jan,
I do belive the” crossed arrows” symbol belongs to H.A.C or the Hamburg American Clock Company. Junghans took over H.A.C in around 1930 but still continued to sell clocks under the H.A.C brand name.
Paul.That is correct Paul. In fact HAC was founded by Erhard Junghans’ son in law Paul Landenburger in 1876, it was then called “Landenburger und Lang”. The name was changed to HAC in 1883. At least that is what I could find out about it.
I llike to do some research on the origin and background of the timepieces I work on
Jan
I finally had the time to look at this clock again and trying to get the amplitude up. I cleaned it once more (just to make sure
), rebushed the pivot holes but had no success, still very low amplitude.
I examined the anchor and found it was verry worn out. A distinct groove was present. So I polished the anchor’s impuls faces untill they were smooth again, making sure not to change the angles. Of course now the drop is too much and there is no provision to lower the anchor to the escape wheel. As you can see in the picture, there are already two holes for the escapewheel, so I guess that someone in the past already moved the escape wheel to accomodate for the same thing. I could do the same and replant the train once more but somehow I feel that it is not the best solution. In my opinion it would be better to make a new anchor. What do you guys think would be better. I know that this small clock is probably not worth the effort, but I am just playing and don’t need to make money on it.
If I were a betting man, I’d bet someone switched out the escape wheel at some point in the clock’s life. But that shouldn’t be a big deal, assuming that it ran after that was done. I would do three things: First, I’d check the escape wheel to see if all the teeth were the same length, and not “sharked” (i.e. worn or bent at the tip); and second, I’d take a close look at the balance assembly, to be certain the arbor was running properly, and that the hairspring was true in both the round and the flat. If you are a member of the National group, look for posts in their forum by Dave Labounty. He has some very good articles he has written over the years, covering hair springing and escapement work for small clocks. (I copied and pasted them into my computer as word documents, but hesitate to post them here, for fear of copyright infringement issues.)
The third option I’d consider, is making a new anchor. Making an anchor is not an insurmountable task. The most difficult part is getting the lock and impulse faces at exactly the right angle, and polished. There is lots of information available online for the mathematics of escapement layout; all you need do is figure out exactly which kind of layout applies to your particular clock, and follow the layout procedures.
Here is a photo of my setup for checking the escape wheel on an English tall clock. You can use essentially the same method with yours. If you don’t have a lathe, any means of chucking it in a pair of runners will do. It could be something as simple as two pieces of wood clamped upright, with indentations in each, to hold the ends of the arbor. You don’t need a dial indicator, either. all you need is a fixed point to set against the end of a tooth, so you can rotate the wheel, and compare tooth heights. (incidentally, you can see two minor problems in this photo: there is a noticeable indentation in one leaf of the escape wheel pinon; and someone ahead of me soldered a replacement tooth into the escape wheel. If you look at it carefully, you can see they did not get it exactly the same form as the rest. a little judicious Emory board work soon put that right, and I was able to move the third wheel slightly on its arbor, to make it bear on an unworn portion of the pinon. I didn’t feel that my skills are up to making and welding in a replacement leaf, and since the clock is original back to the late 1700’s , didn’t want to go replacing parts willy-nilly.)
Thanks Dave for your extensive reply.
I did check the balance and hairspring and they seem allright to my (untrained) eye.
It might be possible that someone replaced the escape wheel. I will follow your suggestions and check the teeth of the escape wheel. FYI, I do have a lathe and a dial indicator, so I guess I will be able to do some decent checking here
I still believe the anchor might have to be replaced (just my feeling ). To better understand the layout and math behind escapements I ordered W. J. Gazeley’s book about escapements and I am looking forward to read it.
In the mean time I will look into the escape wheel and balance!
Thanks again.
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