I'm trying to fix a wall clock which belonged to my great uncle. It's a German-made "Dufa", probably from the 1930s. The chime spring is broken and some teeth are missing off the drum which houses the spring (probably due to over-winding at some point). So I need a new spring and drum. Can anyone think of a company which keeps such parts? Location doesn't matter much as the postage won't be high.
Somwhere near a zero chance of anyone having the exact factory part unless you score and find someone with a wrecker movement. Tooth count diameter and width comparisons may lead you to an interchangeable part, or one that can be cut off on spring barrel and grafted onto another. Expensive option is to scratchbuild a new barrel, less so to graft a section of brass onto the existing barrel and cut new teeth (you need a better excuse to buy some dividing equipment?)
Chime bars are available from either source, as are springs (thickness, width, and length are the required measurements)
Chances are better than just good that the pivot holes are worn (black mung around the hole is the easiest sign to see) and will have to be bushed as well as having the pivots themselves refurbished or replaced.
Try over on alt.horology. It's largley hot air about fashionable wristwatches but there are quite a few knowlegeable repair pro's from around the world hanging out there that may be able to help with parts.
Here's a suggestion for the non purist. Remove the present movement and pack it up carefully, labeling it and doing your best to make sure the next owner of the clock will get it with the clock.
Then, go to Klockit and buy a battery operated chiming movement and put it in the clock. They have all kinds:
I just that for a lady friend last month. She owns a not terribly impressive tall clock which, about 30 years ago, I cleaned, rebushed a few pivot holes, and got running pretty well for her.
She's developed arthritis and it became painfull for her to wind the clock, so I swapped in a Klockit movement. I bored a 2" diameter hole through the back of the case and mounted the movement's little loudspeaker over it so the chime sounds could get out.
The movement runs on a couple of C-cells and has lots of "features" the original mechanical one didn't. Like:
You can switch it to sound either Westminster chimes or just plain "Bim-bam" strikes.
The quarter and half hour strikes can be switched on or off.
There's a volume control for the chime sounds.
You can set it to either chime softer or not at all for any selected nine hour period once a day.
It probably keeps better time than the original one did, particularly if the room temperature swings a fair amount, as it's likely to do here in Red Sox Nation where the increasing cost of heating fuel has nearly all of us all cutting the thermostats way back at night in the winter.
Metal content: I had to make some steel brackets to support the dial, which originally hung off the mechanical movement, and turn a brass reducing bushing to mount the Klockit movement in the dial's center hole.
Jeff (Whose definition of pragmatism is, "If it woiks, use it.")
Take a look at the broken spring first. If it is broken close to an end, just punch a new hole it and reuse it (you will have to make a small die/punch set most likely, nothing elaborate). I did this for a friend some years ago. The repaired spring lasted for at least ~5 years, I lost touch with them after that. It may still be working :)
The suggestion about the holes being elongated is a good one. There are other ways besides bushings, but that is the most elegant way for sure.
When I was a student (without any machine tools) I repaired the barrel once on something from early 1900s using hard (rolled) brass plate about as thick as the teeth. Cut radially into the barrel with a hacksaw where the teeth were missing, cut little rectangles of plate, soft soldered into barrel, finish by hand with files, dress out the penetration into the spring space with suitable burrs. Remember the spring barrel teeth don't need to be particularly accurate.
Thanks for all the suggestions. I'm afraid I'm way too much of a purist to replace it with a quartz mechanism. I like the smell, the tick and the chime. The spring is indeed broken close to the end, so if I can't find a replacement I'll reuse it. The drum is more of a problem. Here's a picture:
It measures 53 mm in diameter (including the teeth), is 23 mm deep and has 80 teeth. You can see the two broken teeth in the picture.
I'll call and e-mail a few clockmakers and see if I can locate a replacement. If not, I had wondered about some way of grafting new teeth onto the drum, but I don't have enough equipment to do that at the moment. I have the broken teeth and had wondered if there was a suitable means for re-attaching them, but right now I can't think of anything. Any ideas?
What equipment DO you have. In times not far gone a job like that one would be tackled with a set of files to cut the teeth, an alcohol flame and a blowpipe to do the soldering in of the new section on wich the teeth were to be cut. Files would be adequate to fit the section of blank brass sheet to the barrel.
You have a near or less than zero chnace of getting the old teeth to fit back in and be useful.
A trip to the library is in order. Most beginner clock repair books will cover the details of a job like this, with pictures.
Some equipment will make the job easier, like a lathe. With a little thought, and some labour, you can set yourself up to cut serviceable teeth with a flycutter and using the other good teeth on the barrel as a reference for indexing. With a lot of thought and sense of adventure, it could be done with a drill press.
A lot of good hand tools (everything common, including needle files) Fairly lame blowtorch (maybe this is a good excuse to buy another) Big electric soldering irons Taps and dies Small drill press Power hacksaw Arc welder Mag drill
My dad has a Myford Super 7 lathe. It's a nice lathe, but it isn't well equipped (especially on the metrology side).
I would find a piece of brass of the same gauge, then do a reverse wedge cut and take the bad teeth out of the drum. Then solder in a new piece of brass and cut the new teeth with a needle file after tracing the teeth onto the new brass with a sharp scribe. Tools: Jewelers saw frame, fine file, soldering tools, scribe, paper
On the spring it should be possible to form a new end.
This site/company has already been suggested, but take a look at the following two links:
especially this link:
It is only $4.95 for the whole assortment pictured. You could probably find one of these with a tooth pattern really close to what you need. Cut a small arc out of the new one (a section with 3 or 4 teeth) and solder/weld it in place of the bad area. This would take some notching, cutting and such, but should be doable. You might even get lucky and find an exact wheel match. Look over the first links page good and see if any of he names match you clock movement.
Of course you can always watch for busted/junk clocks in your area for some parts...
Thanks for the link, Leon. That looks like an attractive set of parts at a pretty low price. It's a pity that they don't give the diameters of the wheels supplied. They look a little small to me, but if I can't find any suitable brass sheet I'll give them a call and enquire.
If you're going to contact them, take a look at this page first:
There is a very good chance you can get the exact part you need from them with a few details. It will cost a bit more though and you will get a whole lot more satisfaction fixing your own broken spring & drum ;-)