Beat rate for Hermle 471-050 94

[lwalper]

I'm in the process of replacing a worn out Jauch 96 with a new Hermle 471-050 94/116 and am not finding a beat rate spec in any of my charts. for that movement. With the way I've currently got it set up Timetrax says it's running at about 3695BPH with a 99cm pendulum. Does anyone have a correct beat rate for this movement?

 

[dickstorer]

It is either 3960 or 3600. If your pendulum is 94 CM in length it will be 3960, 114 is 3600. The beat book does not list 116CM.

Dick

 

[lwalper]

Yep, that's what my book shows. I've just watched it for about 30 minutes and it seemed to be fairly accurate at the 3695 rate -- but probably running a little fast -- hard to tell in that short interval. It's probably supposed to be 3600.

 

[dickstorer]

Could you show us a picture of the numbers on the back of your movement?

 

[lwalper]

Here 'tis

 

[lwalper]

It is either 3960 or 3600. If your pendulum is 94 CM in length it will be 3960, 114 is 3600. The beat book does not list 116CM.

Dick

The sales literature list this movement as a 94/116cm. As you can see, the supplied leader also has two available options -- maybe one for a different/longer crutch?

 

[TEACLOCKS]

471-050 94cm
3960 BPH

 

[dickstorer]

Thanks for the pic. It is 3960. 94CM/66.000. 66bpm x 60min. = 3960

 

[lwalper]

OK, Thanks. Didn't know the 66 was BPM.

 

[Willie X]

If you are using the old pendulum, it will usually be to short. The best/easiest way to correct this is to add about 1/2 ounce of lead weight inside the pendulum bob. I use two 50 cal. rifle balls flattened to about 1/8" thick. Just remove the pendulum stick and drop them in, either side of where the rating rod goes. Willie X

 

[lwalper]

I've been watching it now for about an hour. Timetrax has it at 3696, a long way from 3960. It's currently a little out of beat (I'll fix that), but it's lost about 12 min in that hour. Pendulum's 99cm from suspension post to center of pendulum. Suppose I need to shorten that a bit - take it up to 96. Not sure I'm understanding you Willie - as you said, adding weight will make it go slower.

 

[Willie X]

Yes, most will run fast and you will have to slow the rate a bit

If your clock is running slow you will need a shorter stick. BUT always go by the dial. The dial never lies.

Getting in a big hurry can cost you a lot of time.

Willie X

 

[lwalper]

Right! Time and sticks . . .

 

[TEACLOCKS]

I Cut the End of the leader and rivet a short piece to the middle of the two pieces of the leader to make it longer.
Test how much longer you need by putting the rate nut in the middle of the threads and hang the pendulum with some wire and check the rate Then make the leader that long.
Good luck

 

[Willie X]

If your clock is truely off by 12 minutes in an hour you will need to shorten the stick by about 8 inches! I would recheck that number and 'use tape' to find the correct placement for the bob.

On a 94cm pendulum, a one inch change in pendulum length will change the rate by about 30 minutes per day and (according to your posted 12 minutes per hour rate error) you need a 288 minute per day change??

Tape user, Willie X

 

[TEACLOCKS]

I Cut the End of the leader and rivet a short piece to the middle of the two pieces of the leader to make it longer.
Test how much longer you need by putting the rate nut in the middle of the threads and hang the pendulum with some wire and check the rate Then make the leader that long.
Good luck

Sorry
Shorten