Soundproofing a clock

Another thing...I think this clock could probably benefit from a little lubrication. I recall someone mentioning a thin, synthetic oil which doesn't get more viscous as it evaporates. Is there anything available in small, 3 in 1 sized cans which meets this requirement?

Then I need to decide whether or not to repaint the clock. It was originally black, but I can't decide whether to stick with the grey or not :-).

Chris

Why not replace the drive with a small battery driven movement available in hobby stores. On this side they are about ten dollars with hands. I have adapted hands to keep the original appearance of older clocks.

... unless you want to build circuits. Randy

Slightly OT, but not entirely...

Recently I bought a cool clock on eBay. It's a German "Dehomag" slave clock, probably dating from WWII. The whole thing is made from 1 mm plate, including the dial, which is made by punching out marks in a white-painted plate and laying a black-painted plate behind. Very cool I thought.

Anyway, my plan is to build a circuit to supply the necessary pulses and install it in my bedroom (I have a nice empty space on the wall). I thought being a stepper motor the mechanism would be relatively quiet, but I was wrong. The rotor does abrupt 180 degree turns every minute and has a ratchet to prevent reverse rotation, giving rise to a nice "kerthunk". It is, I think, a little more than I want to try and sleep through.

The clock is missing the original mechanism cover, so I'm thinking of making a new cover with some soundproofing inside. Ideally the cover would be spun or drawn steel, but I think I'll have to make do with finding a container of some sort and cutting off the bottom (unless anyone has a better idea). There will be about 1/4" of thickness for soundproofing material inside the mechanism case, and perhaps more space outside if necessary. Can anyone think of effective, readily available

220 0 article Path: finder4.readnews.com!fnd01.iad01.newshosting.com!textbe01-phx!hwmnpeer02.phx!hw-filter.phx!hwmnpeer01.lga!hwmedia!news.highwinds-media.com!newshub.sdsu.edu!elnk-nf2-pas!elnk-pas-nf1!newsfeed.earthlink.net!pd7cy1no!pd7cy2so!shaw.ca!pd7tw1no.POSTED!53ab2750!not-for-mail X-Trace-PostClient-IP: 70.69.229.66 From: "R. Zimmerman" Newsgroups: rec.crafts.metalworking References: Subject: Re: Soundproofing a clock Lines: 54 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4807.1700 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4807.1700 Message-ID: Date: Sun, 16 Apr 2006 03:15:34 GMT NNTP-Posting-Host: 64.59.144.75 X-Complaints-To: snipped-for-privacy@shaw.ca X-Trace: pd7tw1no 1145157334 64.59.144.75 (Sat, 15 Apr 2006 21:15:34 MDT) NNTP-Posting-Date: Sat, 15 Apr 2006 21:15:34 MDT Organization: Shaw Residential Internet Xref: finder4.readnews.com rec.crafts.metalworking:211220 X-Received-Date: Sun, 16 Apr 2006 00:58:58 MST (textbe01-phx)

Why not replace the drive with a small battery driven movement available in hobby stores. On this side they are about ten dollars with hands. I have adapted hands to keep the original appearance of older clocks.

... unless you want to build circuits. Randy

Slightly OT, but not entirely...

Recently I bought a cool clock on eBay. It's a German "Dehomag" slave clock, probably dating from WWII. The whole thing is made from 1 mm plate, including the dial, which is made by punching out marks in a white-painted plate and laying a black-painted plate behind. Very cool I thought.

Anyway, my plan is to build a circuit to supply the necessary pulses and install it in my bedroom (I have a nice empty space on the wall). I thought being a stepper motor the mechanism would be relatively quiet, but I was wrong. The rotor does abrupt 180 degree turns every minute and has a ratchet to prevent reverse rotation, giving rise to a nice "kerthunk". It is, I think, a little more than I want to try and sleep through.

The clock is missing the original mechanism cover, so I'm thinking of making a new cover with some soundproofing inside. Ideally the cover would be spun or drawn steel, but I think I'll have to make do with finding a container of some sort and cutting off the bottom (unless anyone has a better idea). There will be about 1/4" of thickness for soundproofing material inside the mechanism case, and perhaps more space outside if necessary. Can anyone think of effective, readily available soundproofing material which doesn't cost a fortune? I'm thinking along the lines of some kind of dense foam rubber or cork, but I can't immediately think of a source.

Here are a couple of pictures of the clock. It's 14" in diameter:

Best wishes,

Chris

I know it's an obvious thing to do, but I like building circuits and it destroys the authenticity of quite a collectable clock. I also like the way the hands move once a minute, just like the clocks you see in many large public buildings. I'm also doubtful that your average quartz mechanism would last for long driving those heavy steel hands.

Best wishes,

Chris

But that would be...how can I put it?...bastardising a nice clock. I never understood the eagerness of so many people to retrofit nice clocks with quartz mechanisms. To me, a £5 quartz mechanism is the least interesting thing it is possible to find inside a clock.

:-D

Chris

Well,,,,, just leave it that way,,,,,period and let's forget about it. From here, the sound's not bothering me.

J.P.

snip

Snip

What Diameter is the base of the cover.

I retrofitted about a dozen Simplex units with drawn aluminum covers. They are about 4 1/8" in dia..

They are just laying around here.

Paul K. Dickman

--I'd argue against any lubrication. I remember a guy who made

*really* precice clocks telling me that a good clock should rattle when you shake it; i.e. everything should be loose enough to move freely; if it doesn't you might just have something bound up due to previous owner gunking it up with lube that shouldn't have been there in the first place.

Geez, I never had any problem sleeping thru Latin class with one of those clocks on the wall!

For deadening the sound, think sheet lead. Foam and fiber attenuate high frequencies (clicks and tics) but don't do much for clunks and thunks. (Spectrally-weighted metric units here......) Lead deadens an enclosure so there are no resonances, and the mass reduces housing motion due to pulse stimuli. Less displacement = less sound coupled to the environment. Lead doesn't "ring"; it's acoustically dead.

Sand also works, but lead is easier to work with.

Also, mount the mechanism on resiliant mounts to keep the clunk from coupling mechanically to the structure.

Hi Paul,

Those covers sound promising. I just measured the mechanism accurately and it needs a cover with the following internal dimensions: 100 mm diameter by 40 mm deep. If the covers are 4 1/8" external diameter they should be just right. 4 1/8" internal diameter would be a little large, but still usable I think. Depth could probably vary from 40-50 mm. If they're suitable I'd be interested in buying one off you. If you prefer, you can contact me off-group at snipped-for-privacy@cantabgold.net.

Many thanks,

Chris

I know this is common advice with mechanical clocks, as they are finely balanced, but I'm not sure it applies to a clock driven by a stepper motor. To me the gears look like they would appreciate a little oil.

Chris

Rats! I saw some sheet lead offcuts in a heap of rubbish last week but didn't pick them up. I didn't think I had a use for it. Now I wish I had.

Thanks for the suggestion.

Chris

How about some of the sound deadning material they sell to install in cars to kill the vibration in the door panels etc? Many auto stereo places carry it. It comes in a sheet you can cut with scissors or a knife and most is sticky backed.

Check online for clock oil at salarose.com or timesavers.com. Frei and Borel is another good online source, but more oriented to the professionals in the field.

The pivots in the plates should get oiled. Any oil or grease on the teeth of the gears will result in erratic behavior over time, as the action of the gears works very well to assist the oil drying and becoming sticky.

Cheers Trevor Jones

The lead plate seems an interesting idea. You should give it a go.

Why not put in a clock-style gear motor rated at 1/2 RPM? If you want to get real fancy, put in a 1 RPM motor, and have it shut off after a 180 degree rotation, and then start up at the next minute? You'd need a solid state relay and an optical interrupter sensor to tell when it had rotated far enough.

Jon

--OK, got the picture now. I was thinking it was more like my synchronome, which uses a solenoid to push the pendulum...

Do NOT oil clock teeth. Oil captures fragments of oxides and metal particles and helps create a wonderfully abrasive slurry that will eat the steel pinions meshing with the brass tooth "laps".

In fact, teeth were lubricated until someone figured things out, likely in the 1700-1800s somewhere.

The only exception is pallet surfaces which contact escape wheel teeth. The tiniest bit of oil works wonders, and makes the difference between a running and a non-running clock. Here, wear isn't the issue, it is friction; other wheel and pinion teeth undergo only minimal friction (mostly rolling contact), which, assuming proper alignment (depthing), shouldn't much impede a clock's running.

/mark

Christ> Trevor J>

The more I read about oiling clocks, the more confusing it is. Surely clean oil, of the appropriate viscosity, replenished periodically, will help to prevent wear to the gear teeth? To me, leaving gears running dry seems quite an unnatural thing to do. Is the problem that most people use the wrong oil and let their clock get dirty (i.e., correct, clean oil is good) or is the brass gear train genuinely better off without lubrication? Obviously I want to do whatever minimises wear to the mechanism.

Chris

If I may, Most of the clock movement is not subject to load pressure the lubricant absorbs and in so doing helps prevent metal to metal contact/wear. It's a precise timing issue, (tounge in cheek) not 5:23 gears handling 1000 horsepower through 90 degrees.

So, I think lube would not only affect the timing, but actually add drag to the movement due to the surface/skin effect of fluids.

toosmarttoask