Expected accuracy from home-built clock?

Question

I have just completed my first clock, a simple non-fusee, recoil escapement, timepiece to a design by Colin Thorne.After the initial euphoria that it actually worked, and ran for 8 days at a winding, I have got down to regulating it.

My question for the Group clockmakers is what accuracy of timekeeping should I expect? Careful measurements over the last week show that it ran progressively more slowly as the spring ran down, the total variation in rate over 7 days being about 4 minutes. For the current setting of pendulum, if I set the hands correctly when fully wound, it shows 4 minutes fast at mid-week, then correct again after 7 days. Obviously, I could play around with the pendulum length to make the error - 2 minutes at the beginning, +2 minutes mid-week and -2 minutes at the end of the week if I fiddled some more.

Is this good, bad or indifferent?

Mike

mark · Accepted Answer

i would wind it up at the same time every night

and do calcs from that ...

for a few weeks before you make assumptions that the spring is causing it to loose time as it winds down.

as you've also have to factor in ...

clock oil . i know this will slow a clock down ...for a couple of weeks when first applied ... so after them couple of weeks it will speed up again .

bearings ...they are all brand new ...and still running in.

think you need to give the clock a run-in period of 3 months.

then proceed with some experiments.

all the best.mark

mark · Answer

another thing8 dayswhy do you think they make an 8 day clock rather than a seven day onethe extra day is there so you wind it up on the 7th day ...and it doesnot run down .all the

Cliff Coggin · Answer

That's pretty good Mike. I don't think you can expect better without refining the design by installing a deadbeat escapement or installing a fusee. The rate change is entirely to be expected from a going barrel spring.

Cliff Coggin Wealden Clock Repairs

mike.crossfield · Answer

Excellent.  Just what I wanted to know. Thanks Cliff.

Expected accuracy from home-built clock?

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