Hermie 141/20 movement

[Jeff]

I bought a Hermle 141/20-38cm movement for a clock I'm building. I has a front preformed suspension spring with a hook. What type of bob should I use? The spring is 5"11/16. Total length should be "14.9606. I can get a longer spring. I know I can put on just about any thing, but I want it to look right. The weight has to be right. I was going to call Butterworth, but I ask for the brains first..............

 

[doc_fields]

Butterworth IS the brains behind these movements. Ask the expert.......................gf

 

[Scottie-TX]

My small Hermle compilation does not include your model, but prefix, "one", as in "141", means pendulum I tink. Balance movement would be 140 prefix. Of those I have, those ending in, 020, suffix are five hammer Westminsters, so presume yours is Westminster?
Now here, you use the word, "spring" interchangeably.

What type of bob should I use? The spring is 5"11/16. Total length should be "14.9606. I can get a longer spring. I know I can put on just about any thing, but I want it to look right. The weight has to be right. I was going to call

Not raggin' on ya. Probably gnu at this, but the second spring you mention, I believe is called a pendulum leader - the part that fastens to the suspension ribbon; The part holding the pendulum.
Typically, of those I've had and seen, the pendulum ROD is usually flat brass, about .060 thick and about 3/16" wide. That will slide thru a plain, polished and lacquered bob usually a lightweight one about 3" dia., mebbe 4" at most. The end of the flat rod will be threaded to accomodate reg. nut.
That's gonna be VERY close, but let "MB" the final official word.

 

[Willie X]

Jeff,

This mvt was designed to use a flat brass pendulum rod, about 5/16" wide, which extends through a pendulum made to fit the rod. It has a hole at the top to accept the hook.

You can change the existing rod to a longer 'American' style set-up. This would have a small lead, or lead covered with brass, adjustable pendulum which hooks directly onto the longer suspension spring rod.

Keep the existing suspension spring if possible, just change to a longer rod.

Willie X

 

[eclecticbeat]

The leaders on these are like a two piece feather afaik.

A 23857 and a 19809 from Time Savers will probably fill the bill. An ogee or wood works bob could work too.
I have a clock with a rear mount 151-020. It either a 35 or 38 but there's no drop stamped on it. The pendulum is the same as 23857 but the bob is about 3" in diameter with a shortened 23857. It very close to 12 inches from the center shaft to the middle of the bob but, in this clock, all that's visible is the bob. Great time keeper.

Going another route - Merritt's has generic metal Hermle pendulums for 35, 45 and 55cm available with a 3 1/8" brass bob but I don't know their total lenght.
They have a hook top but if one is long enough, just trim the hook off and make a slot. Might be able to hide the connection behind the dial.


p1676A is the 35cm - B, 45 C, 55.

 

[eclecticbeat]

I thought I had some pictures of it I took but can't find them.
These are just two of the auction pictures. The 141-020 is basically the same except for the high grade plastic.

 

[shutterbug]

Hmmm - that's a whole different deal. Not a Westminster, and the suspension with a hook could hold a longer pendulum as you state. So you'll need a pendulum long enough that the length from the spring hanger to the center of the bob is the length stamped on the movement. I imagine the stated bob size would be about right.

 

[Jeff]

So was that movement made to use only the suspension as the total length, and just hang a bob on the hook?,or could you shorten the length of the spring and install a wood stick with a bob. I tryed the later and got a eratic movement of the pendulum. With a hook on the end of the suspension it is hard to control the action of the pendulum,if you don't use the full length.

 

[shutterbug]

At 15 inches, it's feasible that it's just a rated bob (unless you have adjustment at the spring end). It appears that you have about 15" there already.

 

[Scottie-TX]

I'm not sure which of us don't fully understand the challenge here. You can have a wooden stick if you choose, but it won't be arranged with a bob hanging from the stick. The stick or whatever you choose will need a threaded rod that securely passes thru bob with no wobble, and a reg. nut beneath. Now, as you've mentioned, various lengths of pendulum leaders are available. It's your choice. If rod attachment is too high in case and diffficult to hang, you could use a longer leader that is accessible and of course then, a correspondingly shorter rod to make up the 15"

 

[eclecticbeat]

Jeff,
Everything from the point of suspension on down to it's end, is included in the 'total lenght' of the pendulum. The 'business end' of your suspension spring is the thin flat part. Either end may be shortened but at this stage only shorten the hook end if needed.

It was my experience the crutch fork required near zero tolerance around the wire but the wire still completely free to move fore and aft - side slop here caused a wobble problem on mine. These also have a self-adjusting beat setter, so also look for problems associated with those.

 

[Jeff]

Well the problem I was having was, that if I attached a wooden stick with a bob to a shorten suspension, say total length of spring was "5 1/2,and the stick with the bob was the remaining length to bring it to the required 38cm,I got this woble,which the suspension stopped and the wooden stick would continue to swing causing a woble. I guess the hook was just letting it swing. Maybe this is because I made the suspension spring, and not using Hermle's spring. I would be nice when you bought a new movement that they would furinsh the suspension spring. So like Doc said I've should have ask Butterworth when I got the movement.

Thanks for all the help

 

[shutterbug]

That's a standard suspension, and can be purchased very reasonably from the normal suppliers. 23857 from Timesavers looks like what you need.