Ingraham 8 Day Alarm Movement Beats per Hour

[MLSchlot]

I recently completed repair on an Ingraham 8 Day alarm clock. The clock is running briskly; the lever escapement action looks perfect. However, the clock is losing 20 minutes per day. Does anyone have an idea what my BPH target is? According to Tran's Ingraham reference, my movement looks similar to the 30 hour 2-Spring Alarm Model B, but she runs for a full week between windings. There's nothing in my "Clockmaker's Beat Book" and there are no markings identifying the movement, so short of tearing the movement apart again to count pinions and leaves, I have no idea what my target BPH should be. The attached photo shows the rate lever shoved as far as it can go to increase the rate. It currently measures 16,172 BPH. Any ideas on what the beat rate should be? Many thanks!

 

[Simon Holt]

I don't know the correct rate for this particular clock, but 20 minutes per day is roughly 1.4 %. So add 1.4% to your current beat rate and that would suggest a target of 16398. How you get there I don't know. It sounds like the balance wheel rotation may be insufficient.

Simon

 

[wingardclocks]

Try shortening the hairspring a 1/4".

 

[MLSchlot]

Thank you for getting back to me Gents! That's pretty much what I've come up with. I can get the bulk of the error out with the rate adjuster. If I shorten the hairspring a touch more than the current regulator delta, and adjust the collet to get it back in beat, I should be in good shape. It's funny. The clock looked like it had never been dinked with, and I was very careful to note the pinned position of the hairspring before I started work. Once I complete my run-in, I'll be in better shape for the future once I update my Beat Book with my final BPH measurement on this movement. I'd love to know what Ingraham's spec was.

 

[Willie X]

You can shorten it without cutting ...
Put the pin back in, not to tight, at exactly 1/8" shorter. Then take that 1/8" as a given for future adjustments.
Going by a calculation can get you to the right place but it takes a good bit of time and there is always the chance of an error. So, I always go by the hands. The hands never lie.

An ultrasonic cleaner will cause the trouble you are having and you clock does have that 'look' to it.

Willie X

 

[MLSchlot]

Thanks Willie. Yes. The clock was disassembled and run through the ultrasonic cleaner. But, that didn't include the balance and hairspring. The ultrasonic will definitely alter the strength of a hairspring or suspension spring, so those parts are always excluded. The balance and hairspring are run through my old L&R watch cleaner, which is agitation cleaning only.

 

[Ravens_Time]

I just recently overhauled the same movement. Or at least it appears to be the same movement. I get very good balance rotation and it’s an excellent time keeper. I’m getting a 16328 BPH rate on my time trax. Hope this helps.

Pat

 

[MLSchlot]

Thanks Pat; I'll let you know. I had to set it aside for a bit, but I should be back on it by Friday.

 

[ARw]

When I finally got my old tin can Ingraham Indian Alarm open I found the balance wheel hanging from the spring. I got it back in place, turned in the bearing screws a bit, put in a touch of oil and it's been keeping near perfect time for 2 days now. It's a 1913 patent. Were these all 8 day clocks?

 

[dickstorer]

Pin Lever escapements like yours are most often 14400 or 16200.

 

[MLSchlot]

I can safely say that 14400 won't work on my Ingraham. The 16200 setting appears to be closer to my ballpark. I should know some time tomorrow.

 

[MLSchlot]

Well, she's dialed in and keeping perfect time at 16,397 BPH, so I'd guess the Ingraham design spec for this movement model is 16,400 BPH. In any case, that's what's getting added to my Beat Book in the Ingraham section. Thanks to everyone for their suggestions and comparison movement info!

 

[shutterbug]

I don't have my beat book in front of me, but I recall two major beats counts that most non-pendulum clocks adhere to. My memory (which is not always reliable) tells me that 16,400 BPH is one of them.

 

[MLSchlot]

The two beat counts I seem to run into the most are 18,000 BPH and 14,400 BPH, but they are usually reserved for what I consider to be "high performance" movements. I pretty well expected this clock to run much slower than 16400 BPH. I thought maybe 14400. I've seen a bunch of Schatz 2 jewel lever movements that run at that rate, but I was betting this one would be much slower. Something more like an old Hermle Floating Balance running at 9000 BPH. So much for presumptions.