another master clock from craigslist (standard electric time)

[bruce linde]

five days after posting about a newly acquired IBM/ITR master clock ( IBM/ITR 17-7 - wall art ) i saw this standard electric time master on craigslist for $60.

it had a base (and no hanger)... and was set up as a standing clock. i thought it looked funky so i didn't even take the base with me. i like wall clocks with seconds pendulums, so there you go. i'm not sure the paint job is original, but it's grown on me.

everything was good except for the escape wheel, which had been trashed. we (my clock mentor and i) had to seriously shorten the escape wheel teeth (both of us) and re-sole and adjust the verge (him) but it now runs great.

note: i somehow hit the slo-mo switch when shooting the first video... kind of like it.

 

[brian fisher]

that is so cool bruce. i really dig that dial.


i see the coils at the bottom of the movement, but i really cant figure out how it works.

 

[gleber]

Yes, tell us more about how it works... It looks like the coils engage a ratchet wheel, but what maintains power? Is there a spring?

Great find!

Tom

 

[Peter John]

I think the coil spring on the minute shaft is what provides power. It is a self winding clock. Contacts close every minute or so to wind. Peter

 

[bruce linde]

i'll try to explain... even if i don't fully understand the electronics, i see what's happening mechanically.

there is a cam on escape wheel arbor, between the escape wheel and front plate.

every 60 seconds it comes around and lifts the long skinny silver auto-wind trigger (second arrow in first photo). when the cam passes by and lets the trigger drop back down, it makes a new connection with the piece under it and triggers the coils... which pulls the auto-wind arm (bottom arrow first photo, top arrows second photo) toward the coils.

as the lower right chunk of steel on the auto-wind arm moves from lower right toward the coils (lower left), the left side of the auto wind arm (bottom arrow first photo) lifts up... and the pawl on the end of it (third arrow from bottom, first photo) pushes up against the winding wheel, winding it one notch.

misc:

- the electronics seem to be converting 110 VAC to 26 VAC
- the winding seems to happen more often than needed... keeping it fully wound
- if the power goes out, it seems like it will turn for about one and a half to two hours before stopping
- there is a slight 'thunk' when it winds, but kind of a muted one if it's fully wound... otherwise you definitely hear a combination thunk+click... but no way as loud as a stromberg or gents... in fact, i was thinking of moving this one into the house and letting it run all the time in place of the stromberg, which would get relegated to the garage so it could run all the time as well... but am going to stick with how things are.

current morning ritual is:

1. start the gents C7 master, master bedroom. i have an alarm that goes off... as soon as it does i walk back into that room and start the pendulum swinging without having to set the time... got it coordinated.
2. go to the guest room and start up the stromberg... have to re-set the time every time, no big
3. go to my office and wind the seth thomas pillar and scroll
4. everything else

 

[gleber]

I think the coil spring on the minute shaft is what provides power. It is a self winding clock. Contacts close every minute or so to wind. Peter

Thanks Peter,. I suspected something like that and should have looked closer. I was expecting more like a conventional flat coiled spring and didn't see one.

Tom

 

[bruce linde]

i'm still trying to get the auto-wind working consistently... sometimes it does, and sometimes it doesn't... will look for more info about tweaking in electric horology when i get a chance...

 

[Jim Andrews]

I have one of these that runs very well. There's probably a nice oak or mahogany case under the white paint, but for $60 I'd have grabbed it as well. Nice find.

 

[bruce linde]

I have one of these that runs very well. There's probably a nice oak or mahogany case under the white paint, but for $60 I'd have grabbed it as well. Nice find.

when i first saw it i thought it looked a little chinese restaurant-ish, but have grown to like the way the lighter case makes the pendulum and dial 'pop'... it's also in the garage next to my workbench and brightens things up a bit.

 

[bruce linde]

I have one of these that runs very well. There's probably a nice oak or mahogany case under the white paint, but for $60 I'd have grabbed it as well. Nice find.

do you think i should strip it and refinish it?

 

[gleber]

I would. It looks sort of modern like that and not showing its true heritage.

Tom

 

[bruce linde]

all right... it's on the 'eventually' list...

 

[Jim Andrews]

do you think i should strip it and refinish it?

That's your call. Stripping it would be a ton of work for sure. I'd look at the crown on the top side and do a test area to see what might be underneath. They were known for putting the nicest grain in the back of the case behind the pendulum where it was most visible. It would look nice without the paint, but again, how much effort do you want to put into it?

 

[bruce linde]

if there comes a time when i’m sitting around without multiple clock projects in pieces in my living room and all over the kitchen table, and it’s going to rain all week so no tennis, and i’m bored out of my mind... maybe. it’s pretty easy to use paint remover... i have a harder time being patient w multiple coats of stain, sanding each one before putting on the next one, etc.

so... maybe someday.

 

[Jim Andrews]

good plan... I'd add this final comment. The oak cases were most prevalent, or at least that's what I've found to be most common. I once saw one in what I thought was cherry - a deep red finish anyway - now I suspect it was more likely mahogany, and I remember it to this day. It was in a public school office so it was unobtainable. I'd at least do the test area and see what's beneath. If you have what I'd consider the very rare reddish wood cabinet, that would greatly elevate the priority of the restoration project IMO. Good luck on the results, but you'll win regardless.

 

[Kevin W.]

Great looking clock. I would strip it as well. You sure get lucky my friend.

 

[bruce linde]

one thing i noticed is that jeffrey woods' 'standard electric time clock technical information doc' (attached) says that the mainspring should be three or four winds around at most... mine is probably double that, which may explain why 1) the auto-wind doesn't fully wind the clock and 2) the clock will run happily with even a few ticks of wind. i think someone went a little crazy with the mainspring and put in too much of one.

also according to woods... the problem with these babies is that they would continue to try to wind even when fully wound... causing wear to the escape wheel teeth over time... exactly as my clock mentor and i found when we looked closely at the escape wheel.

the good thing about the mainspring in mine is that the auto-wind may strain a bit against a too-strong mainspring but won't be doing any further damage to the escape wheel teeth.

thoughts?


[pdf]530165[/pdf]

 

[gleber]

I have trouble picturing wear on the escape wheel due to over-winding. What is happening in that state to cause the wear?

Also, is there no "pressure relief valve"? It seems like if the wind action doesn't equal the run action, it will either stop or wind more an more. A way to regulate that would be to have the winding ratchet slip somehow when the wind is full.

Tom