Here's a question for the clockmakers...
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.
Any suggestions will be appreciated.
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.
On Mon, 13 Mar 2006 17:03:11 -0700, Trevor Jones wrote:
If alt.horology isn't working for you on this, then the crew at the NAWCC
board is another option. http://nawcc-mb.infopop.cc/6/ubb.x
John Plewes book on Repairing Pendulum clocks is a great place to start to
flush out the skill set. I found it still available recently at
http://www.leevalley.com ISBN - 0-918845-22-X It will help you answer
some of the questions you might not know enough to ask if you aren't
familiar with some of the "gottchas" that Trevor mentioned.
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
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.")
On Mon, 13 Mar 2006 23:36:13 +0000 (UTC), Christopher Tidy
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
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
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.
Thanks for the help.
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
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've got plenty of time to experiment and learn.
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.
"Christopher Tidy" < firstname.lastname@example.org> wrote in message
On Sat, 18 Mar 2006 02:54:28 +0000 (UTC), Christopher Tidy
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.
On Mon, 20 Mar 2006 07:55:49 +0000 (UTC), Christopher Tidy
If you're going to contact them, take a look at this page
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 ;-)
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