Restoring 8-day weight driven movement...

[TomT]

I am restroring an 8-day weight movement. I checked out and polished all the pivots and checked gears for wear and/or damage. All appears generally servicable.

When I got the movement the verge was missing and I had to replace it. The escape wheel is 34 teeth. I set up the pallet clearances per Seven Conover's book "Clock Repair Basics". Per his recommendations, I took the number of teeth between the pallets (8) added two and measured the distance between these (10 teeth 21.5mm). I subtracted one drop and one lock (1.5 mm), then set the pallets to this figure (20mm).

I used Paul's fish-scale recommendation to power the clock (10lbs) and set the clock in beat.

It has a nice even beat, but after about 5 minutes seems to get "out-of-beat".

I went back and checked all the gear teeth for bending and inspected the lantern wheels for excessive wear. I can't find anything, but it seems like something is coming into play.

I marked teeth on all gears and the escape wheel to see if the problem occured at some particular point (no luck so far).

Questions:
Is there a common problem that might cause this problem?

Is my procedure for setting up the verge correct, or is there a better way?

Thanks for any suggestions.

Tom T

[TomT]

I am restroring an 8-day weight movement. I checked out and polished all the pivots and checked gears for wear and/or damage. All appears generally servicable.

When I got the movement the verge was missing and I had to replace it. The escape wheel is 34 teeth. I set up the pallet clearances per Seven Conover's book "Clock Repair Basics". Per his recommendations, I took the number of teeth between the pallets (8) added two and measured the distance between these (10 teeth 21.5mm). I subtracted one drop and one lock (1.5 mm), then set the pallets to this figure (20mm).

I used Paul's fish-scale recommendation to power the clock (10lbs) and set the clock in beat.

It has a nice even beat, but after about 5 minutes seems to get "out-of-beat".

I went back and checked all the gear teeth for bending and inspected the lantern wheels for excessive wear. I can't find anything, but it seems like something is coming into play.

I marked teeth on all gears and the escape wheel to see if the problem occured at some particular point (no luck so far).

Questions:
Is there a common problem that might cause this problem?

Is my procedure for setting up the verge correct, or is there a better way?

Thanks for any suggestions.

Tom T

[lpbp]

It's hard guessing what's going on wihtout seeing what you have. What kind of movement is it, and what kind of verge is it? Did you make it, or use a stock replacement?

Larry Pearson, FNAWCC #35863 L138
candidate for Director

[gre406]

Tom..First, what is the movement you are working on and second, how many teeth of the
escape wheel does your verge ungulf?? Should it not be an odd number of 7, 9 or 11 ??

Geo
NAWCC#78594

[TomT]

The movement is an unsigned 8-day weight movement. I tried Phil's suggestion of setting the clock into motion very lightly to confirm that it was actually in beat under clock-power. This helped get the beat correct. I then used Phil's fish-scale trick to determine the correct weight for the movement. It ran fine with ten pounds of pull and kept running until it reached about 4 1/2 lbs. I now have it running with a 5 lb weight and it seems to stay steady and in beat.

As to the number of teeth embraced by the verge, it is a 34 tooth escape wheel and the verge embraced 8 teeth. I then used the formula provided in the book previously noted (add two teeth to the embraced number, measure the distance, subtract one lock and one drop (1.5 mm) and set the pallets to this final distance.

10 teeth measured 22.5 mm, I subtracted 1.5mm and set the pallets at 21mm. I played with the pallet engagement depth a little then bent the crutch until I got it into beat.

It seems to run reliably and in beat, but I still wonder if there is some better way to optimize the escape mechanism.

If you have a better or different approach, please share it.

Thanks to everyone who has provided suggestions. I haven't been doing clocks long, but I sure enjoy it and appreciate that there are folks out there willing to share their exprience.

Regards,
Tom T

[gre406]

Tom T....If it keeps running, put on a pair of hands and let's "time it"..

Are you able to photo movement and email pics??

Its hard to explain the arc relationship of the verge to the escape wheel without a picture.. I
will have to look if I can find a book to show this better...

Geo
NAWCC#78594

[TomT]

Here are some photos of the movement and escape mechanism.

Thanks........

http://www24.brinkster.com/justtom/EightDay.htm

[gre406]

TomT..thanks for the photos..First thing I am guessing this is a counter clockwise rotation of the escape wheel..(ccw)..It looks also as the crutch may work better on the right side of the saddle.

This photo is of a 42 tooth escape with 9 teeth between the pallets..

http://userweb.nni.com/gre406/Es3.jpg

I see now you have 9 teeth between the verge pallets which should work.. but maybe seven would work better with the 34 tooth wheel..The pallets seem a little thick..You may want to take a little off the top of the left side and polish it out.

http://userweb.nni.com/gre406/Es5.jpg

This job is hard enough without the old verge to match so I hope this helps a little..

Hope someone else will jump in and add more..

Geo
NAWCC#78594

[This message was edited by gre406 on February 05, 2003 at 13:51.]