Willmann Pendulum Rod Length

[David M.]

Recently I posted about the two weight Willmann movement that I bought. I did not come with weights, pulleys, case or pendulum.

I've cleaned it, polished the pivots and bushed most of the time train and some of the strike.

Estimated I might need a 21" pendulum rod (based on my faulty calculation). Added 3 ½# of weights to the time side and gave the 2# bob a nudge. Ran steady, but the second hand (on the escape arbor) was making a rotation about every 45 seconds. Need more pendulum rod! I finally wised up and clipped my beat counter to the unit looking for 3600 BPH. Ended up adding another 10 inches!! From hook to center mass of the bob is 39 ½", to the bottom of the bob is 41 ¼".
Please ignore the blue tape I used to add temporary weights and shaft length.

Are they normally this long?? Second hand is sweeping at 00:59:72, which when the new pendulum rod is made with screw regulator on the bottom I think I can get even better.
Thanks everyone!
David

 

[bruce linde]

seconds beating clocks have a (roughly) one meter pendulum. your initial assumptions were clearly off the mark.

and… that one meter is not the total length but the distance from the suspension spring flex point to the center of mass of the bob.

 

[Tim M]

A revolution in 45 seconds is normal for a vienna regulator movement of this type. Odd, but correct in this instance even though the dial might list 60 seconds.

 

[JimmyOz]

Are they normally this long?? Second hand is sweeping at 00:59:72, which when the new pendulum rod is made with screw regulator on the bottom I think I can get even better.

I think you should put the motion works on and the hands and let us know how long it take to do an hour?

 

[bruce linde]

I think you should put the motion works on and the hands and let us know how long it take to do an hour?

agreed... there is that class of vienna regulators where the second hand goes around in 45 seconds... the only way to know for sure is to put the hands on and see how she blows. if it is a vienna regulator movement, you will see it running slow within minutes.

 

[David M.]

agreed... there is that class of vienna regulators where the second hand goes around in 45 seconds... the only way to know for sure is to put the hands on and see how she blows. if it is a vienna regulator movement, you will see it running slow within minutes.

Well, that's a beautifully practical approach. I'll put the dial and at least the minute hand on tomorrow and report back.
Yes, the second hand dial area shows 60 seconds at top. Also, the second hand is on the escape arbor. I counted the teeth on it and it was 30 teeth. I just counted the periods (back and forth swings) for one minute and counted 30. So, 1 every 2 seconds. I found an online pendulum calculator and plugged in the 2 second period and came up with a pendulum length of 39.12"; very very close to what I ended up with in making one by trial and error using 3600 BPH as my target. This is all so much fun for me--really is.
Tomorrow I'll do as you kind folks are suggesting, a perfect idea!!
Thanks for being here!!
David

 

[bruce linde]

recently went through the same exercise, thinking i had a sweep second hand seconds beating movement…. ran great w a long pendulum but when i put on the hands on it was clear that… despite the 30 tooth escape wheel… it was a classic vienna regulator movement, wanting a classic (i.e., shorter) pendulum… and ran really slow w the long pendulum.

since i found only willmann VRs and no tall case clocks (admittedly a half-arsed search), i predict youll go back the the shorter pendulum… but pls do keep us posted!

of course, if you don’t care about it telling time, you could just mount it on a board and have it be pendulum wall art w the longer pendulum….

 

[David M.]

recently went through the same exercise, thinking i had a sweep second hand seconds beating movement…. ran great w a long pendulum but when i put on the hands on it was clear that… despite the 30 tooth escape wheel… it was a classic vienna regulator movement, wanting a classic (i.e., shorter) pendulum… and ran really slow w the long pendulum.

since i found only willmann VRs and no tall case clocks (admittedly a half-arsed search), i predict youll go back the the shorter pendulum… but pls do keep us posted!

of course, if you don’t care about it telling time, you could just mount it on a board and have it be pendulum wall art w the longer pendulum….

Bruce
A pendulum wall art would be fun. But finding out the truth will be more fun. Its been fun so far----lets see.
David in Widsor, Ca enjoying the rain---so far

 

[David M.]

Bruce
A pendulum wall art would be fun. But finding out the truth will be more fun. Its been fun so far----lets see.
David in Widsor, Ca enjoying the rain---so far

Bruce, Tim and JimmyOz
You all were right. I'm back to a much shorter rod----pretty close to my original calculation. And now the 60 seconds hand completes its round trip in 45 Seconds. Looks like a BPH of around 4860; my original calculation though I often get it wrong (not sure why).
So, is there a good explanation as to why the normally exacting Germans would do this??
Thanks for your input. You folks are great
All my best
David

 

[bruce linde]

I’ve asked this question multiple times… The best we can come up with is that drilling a hole in the dial and sticking a second hand on was an extra feature that didn’t cost the manufacture much. They probably been added chapter rings, even if bogus. There is a famous anecdote about a doctor checking a patient’s pulse rate one of these clocks and thinking the man was dying. As is so often the case we will never know. My question would be: how hard would it be to set up gearing for a vienna regulator sized clock that actually did beat seconds with a shorter pendulum?

 

[David M.]

I’ve asked this question multiple times… The best we can come up with is that drilling a hole in the dial and sticking a second hand on was an extra feature that didn’t cost the manufacture much. They probably been added chapter rings, even if bogus. There is a famous anecdote about a doctor checking a patient’s pulse rate one of these clocks and thinking the man was dying. As is so often the case we will never know. My question would be: how hard would it be to set up gearing for a vienna regulator sized clock that actually did beat seconds with a shorter pendulum?

Thanks Bruce

 

[JimmyOz]

Maybe they looked at the cost of re-tooling and some marketer thought "hey, why bother just make it look like it is 60 seconds" I am sure a distant relative worked at Volkswagen and had the same idea about emissions!!!

 

[David M.]

Maybe they looked at the cost of re-tooling and some marketer thought "hey, why bother just make it look like it is 60 seconds" I am sure a distant relative worked at Volkswagen and had the same idea about emissions!!!

I still think its a bit odd, but I like the movement---my first weight movement.
Thanks everyone-
David

 

[Willie X]

The minute hand will nearly always speak the truth. Willie X

 

[David M.]

Hello All---Again!!
Still working on my Willmann Two Weight Project:
We, I now have made the correct length pendulum to make the clock run at the correct rate for it to keep good time. Its still on a test stand, because it came without a case (or pendulum, weights, pulleys, etc). I attached enough 150# braided fishing line to have the bottom of the weights (when at the end of their line) be about level with the tip of the pendulum rate bolt. This made the clock run for about 5 days. I could increase the length of the line to make it a 8 day clock, but the weights after 8 days would be about 13" below the pendulum. That would make a very tall case and might look odd.
So, my question is: is it common for a "regulator style clock" to run for less than 7 or 8 days? Or do some clocks like this have longer weights??
Thanks for looking in
David

 

[new2clocks]

I’ve asked this question multiple times… The best we can come up with is that drilling a hole in the dial and sticking a second hand on was an extra feature that didn’t cost the manufacture much.

This answer appears to be the most reasonable explanation to the 45 seconds minute dial.

There is an article in the October, 2008 Bulletin by the late Doug Stevenson that addresses the question(s) that Bruce (and many others) have brought forward. The name of the article is "Seconds Thoughts on German Viennas".

Doug found evidence in an 1883 Lenzkirch catalog that Lenzkirch were offering wall regulators with either a sweep seconds hand or subsidiary dials, where the seconds hands took 60 seconds to complete its revolution. (Loose translation from the catalog - "correct" seconds hand.) Lenzkirch also offered wall clocks without the seconds hand. However, if you wanted a clock with seconds hands (my assumption - you do not want to pay the price for the "correct" hands), which Lenzkirch referred to as "little seconds", you can special order these clocks with the little seconds and pay the same price as the wall clock without seconds hands. Of course, these "little seconds" will take only 45 seconds for a complete revolution. And, even more interesting, as Doug stated, these "little seconds" clocks would entail an arbor extension, a seconds hand, a different dial, and the special ordering.

Doug threw out some possibilities off the top of his head as to why Lenzkirch may have done this. His one possibility is an interesting one - perhaps Lenzkirch didn't charge extra for a clock with "little seconds" because they needed to compete with lesser firms. So, (my interpretation) rather than being a production cost issue, the offering of the "45 seconds / little seconds clock" was a market share issue.

Regards.

 

[David M.]

This answer appears to be the most reasonable explanation to the 45 seconds minute dial.

There is an article in the October, 2008 Bulletin by the late Doug Stevenson that addresses the question(s) that Bruce (and many others) have brought forward. The name of the article is "Seconds Thoughts on German Viennas".

Doug found evidence in an 1883 Lenzkirch catalog that Lenzkirch were offering wall regulators with either a sweep seconds hand or subsidiary dials, where the seconds hands took 60 seconds to complete its revolution. (Loose translation from the catalog - "correct" seconds hand.) Lenzkirch also offered wall clocks without the seconds hand. However, if you wanted a clock with seconds hands (my assumption - you do not want to pay the price for the "correct" hands), which Lenzkirch referred to as "little seconds", you can special order these clocks with the little seconds and pay the same price as the wall clock without seconds hands. Of course, these "little seconds" will take only 45 seconds for a complete revolution. And, even more interesting, as Doug stated, these "little seconds" clocks would entail an arbor extension, a seconds hand, a different dial, and the special ordering.

Doug threw out some possibilities off the top of his head as to why Lenzkirch may have done this. His one possibility is an interesting one - perhaps Lenzkirch didn't charge extra for a clock with "little seconds" because they needed to compete with lesser firms. So, (my interpretation) rather than being a production cost issue, the offering of the "45 seconds / little seconds clock" was a market share issue.

Regards.

Thanks New2Clocks
Well that is interesting indeed. "We can give an impressive extra dial to look at, just don't expect it to use it to check the time on anything". Well, this is my first weight driven clock and I like it.
But my question remains: Is it common for them to run between rewinding only 5 days
Thank you!
David

 

[bruce linde]

i would think not... and that maybe the weight cord is too thick... what is its diameter?

 

[David M.]

i would think not... and that maybe the weight cord is too thick... what is its diameter?

Hi Bruce
0.62 mm, fits perfectly in the winding barrel grooves.

 

[bruce linde]

all i can offer is that my seth thomas #1 w/ round terry movement ran for 4 days when i got it... and the weight cord was .8mm in diameter. i went to .4mm diameter braided kevlar fishing line and now get a full 8 days.

 

[David M.]

all i can offer is that my seth thomas #1 w/ round terry movement ran for 4 days when i got it... and the weight cord was .8mm in diameter. i went to .4mm diameter braided kevlar fishing line and now get a full 8 days.

Bruce
I sure can't wrap my brain around that----but I'm going to Amazon right now and order some 0.4 mm braided kevlar fishing line. I will report back I promise!!
Thank you for your input-
David

 

[bruce linde]

think of it this way... the weight is going to drop x amount every day. if the cord were 1" thick, you'd have your x amount of daily weight drop and (let's call it) y rotation of the winding barrel. if you went to a 1/2" thick cord you'd have less x because the thinner cord wouldn't rotate the barrel as much... but you'd still have the same weight providing the same power. less daily weight drop = less winding barrel rotation = longer run time. yes?

 

[bruce linde]

(my interpretation) rather than being a production cost issue, the offering of the "45 seconds / little seconds clock" was a market share issue.

i think that's spot on... but i'm going to explain it to my non-clock friends who continue to struggle to wrap their brains around why anyone would do this as: somewhere between market share and a low-cost way to provide multi-tiered pricing and options... even if at the cost of actual accuracy.

 

[David M.]

think of it this way... the weight is going to drop x amount every day. if the cord were 1" thick, you'd have your x amount of daily weight drop and (let's call it) y rotation of the winding barrel. if you went to a 1/2" thick cord you'd have less x because the thinner cord wouldn't rotate the barrel as much... but you'd still have the same weight providing the same power. less daily weight drop = less winding barrel rotation = longer run time. yes?

Bruce
Thanks. Makes sense that way. As soon as my order (0.32mm) arrives I'll pop the new line in and start a new trial. Who wouldn't love this stuff-
David

 

[Willie X]

The same drum will hold more of a thinner line and this run longer. However, the weight drop per day won't change much, just a little, due to the difference in centers. The drum would effectively be reduced by about .4 mm (?), which would change the drop per day just a bit, maybe 1.5mm per turn. The math is pretty simple but would require the diameter of the drum and exact line diameters.

The 'per day weight drop' varies greatly from one clock to another.

My guesses would be that: you are running the clock directly and it's supposed to be compounded with a pulley on the weight, or the movement had a long case.

Your clock should run 8 days, or at least well past 7 days.

Willie X

 

[bruce linde]

willie - that makes perfect (and informed) sense… but my st 1 weight was compounded and going to the smaller diameter cord did take take it from a 4-day run time to 8. do think the smaller diameter helped with winding and pulley? more cord on the winding barrel? as i remember the weight was originally bottoming out after 4 days…. ??

 

[Willie X]

Bruce,
Those have a small drum so the cord size would make more difference.

I don't know the details on the clock in question but the pendulum does looks to long.

Do you think the OP is rating it by the second hand and it's a 45 second bit rated to 60 seconds?? That would explain the extra long pendulum but not the to short run time! Course it's not unusual for a weight to drop way below the pendulum and 13" isn't close to way.

I don't even know what a "Willman" movement is? Looks like a 80 beat regulator movement?

David,
Did you do a tooth count beat calculation, or put the hands on it for a 24 hour run yet? Either will give you solid information. Then you can figure things out.

The answers are always there. It just takes a while to put the pieces together sometimes ...

Willie X

 

[ragobo]

Did you calculate the gear transmission ratio from the minute driving wheel up to the escape wheel?

That will give you the definite bph of the movement.

The minute arbor /wheel should turn at 0.1º/s (i.e. one revolution every 3600 seconds).

From that you can translate this velocity up till the escape wheel. If it comes up being 6º/s then your movement should beat at 3600bph

 

[new2clocks]

I don't even know what a "Willman" movement is?

I believe the OP's movement has been identified as being manufactured by the German clockmaker A. Willmann & Co.

Regards.

 

[David M.]

The same drum will hold more of a thinner line and this run longer. However, the weight drop per day won't change much, just a little, due to the difference in centers. The drum would effectively be reduced by about .4 mm (?), which would change the drop per day just a bit, maybe 1.5mm per turn. The math is pretty simple but would require the diameter of the drum and exact line diameters.

The 'per day weight drop' varies greatly from one clock to another.

My guesses would be that: you are running the clock directly and it's supposed to be compounded with a pulley on the weight, or the movement had a long case.

Your clock should run 8 days, or at least well past 7 days.

Willie X

Willie X
Thank you. Your explanation makes pretty good sense. I'm going to try the smaller diameter line first, but I'm not too hopeful that will give me 7 days vs the 5 I'm getting now. If that fails I'll give the compound pulley a try. I will report back on all this---promise.
Its so nice to get input by simply typing in a question or issue.
David

 

[David M.]

Willie X
Thank you. Your explanation makes pretty good sense. I'm going to try the smaller diameter line first, but I'm not too hopeful that will give me 7 days vs the 5 I'm getting now. If that fails I'll give the compound pulley a try. I will report back on all this---promise.
Its so nice to get input by simply typing in a question or issue.
David

Hello All
I did do a calculation with the wheel gears and pinion leaves and came up with 4860 BPH. I've had the clock dial in place for quite a few days now and set the pendulum to that rate and the clock is keeping pretty darn good time. As you can see, I'm using a pulley on the weight. By my reading its a two fall compound right now. That picture was taken when the clock stopped at the end of the winding barrel line, about level with the pendulum bottom tip. That was about 5 days run. By my calculations, I'd need to add another 9" of drop to get 7 days run. I've been running o.62 mm line. I've ordered 0.32 mm line and will give it a try when it arrives Tuesday.
Thanks everyone-
David

 

[bruce linde]

i would recommend much smaller weight hooks... perhaps half the diameter of one of the pulleys instead of larger than them? you're giving up the better part of a day's run time right there. if the weights have hooks and not loop ends, you can slightly widen the pulley harnesses to fit, or carefully file down the width of the weight hooks to do the same, and then lose the s-hooks altogether.

 

[David M.]

i would recommend much smaller weight hooks... perhaps half the diameter of one of the pulleys instead of larger than them? you're giving up the better part of a day's run time right there. if the weights have hooks and not loop ends, you can slightly widen the pulley harnesses to fit, or carefully file down the width of the weight hooks to do the same, and then lose the s-hooks altogether.

Bruce
Great idea staring me right in the face. Those were the only brass "S" hooks at my local hardware store. I'll take them off when I re-line the barrels.
David

 

[bruce linde]

can we see the current weight hooks? you might be able to replace them with more appropriate j-hooks so you wouldn't even need s-hooks. you might also be able to file a slot into the existing enclosed hooks to turn them into upside-down j-hooks that would hook onto the pulleys.

pls also provide the dimensions of the weights? you might not have vienna regulator weights, which are typically 3.5 inches tall.

 

[David M.]

can we see the current weight hooks? you might be able to replace them with more appropriate j-hooks so you wouldn't even need s-hooks. you might also be able to file a slot into the existing enclosed hooks to turn them into upside-down j-hooks that would hook onto the pulleys.

pls also provide the dimensions of the weights? you might not have vienna regulator weights, which are typically 3.5 inches tall.

Hi Bruce, et.al
Please see pics. When I saw your earlier suggestion I tried removing the "S" hook from the strike train and the weight fits nicely directly in the weight hook. I started a new test run at 10AM and want to check it again in 24Hr on the time time weight to see the drop in 24Hr.
The weights are from TimeSavers and were referred to as vienna regulator weights. They are 3 pounds and ~14mm (~5 1/2") tip to tip.
David

 

[bruce linde]

yes, i have a set of those... and they are longer than the weights on all of my other viennas (which are in the 3.5 - 4" range).

your next measurements will be helpful... they may show that 4" weights and losing the s-hooks would indeed give you a full 8 days... even before going to the smaller weight cord.

 

[David M.]

yes, i have a set of those... and they are longer than the weights on all of my other viennas (which are in the 3.5 - 4" range).

your next measurements will be helpful... they may show that 4" weights and losing the s-hooks would indeed give you a full 8 days... even before going to the smaller weight cord.

Bruce
I'll try to track down shorter and fatter weights. I'm still going to try the smaller diameter line when it arrives.
David

 

[bruce linde]

lots of shorter ones typically available on ebay....

 

[Willie X]

That 8th day can be 'hard to get' on these clocks. Looks like you're on the right trail now though. Willie X

 

[David M.]

lots of shorter ones typically available on ebay....

Hello All-
I have now run the clock for 24 hours. I build things all the time as a hobby and simply can not get by without blue tape (masking tape). Yesterday morning (I wind my clocks on Sunday AM) I wound up the clock in question at exactly 10AM Sunday. I ran a strip of blue tape from top to bottom on my test stand. I marked on the blue tape level with the bottom of the weight. Today (24 hours later) I marked again on the blue tape level with the bottom of that same weight. In 24 hours the weight drop was 5.7 mm. When fully wound up (with "S" hook removed) I have 39.0 mm of space below the weight. The clock is on a test stand now waiting for me to build a case. The 39.0mm distance puts the bottom of the weight roughly level with the tip of the pendulum bob. When I build my case I'll give myself a bit more room. 39.0mm divided by 5.7mm/Day gives me 6.8 days. I can easily design in a bit taller case to get me at least a full 7 days.
I'll keep checking every 24 hours to confirm this data. The smaller diameter weight line arrives tomorrow. I'll give the clock a couple of days running on the current thicker line before I commit to the switch. Then run the same test again to see what that does.
I'm happy with the test so far, but one day of data is not enough. I'll report more as I go.
Thank you everyone!
David

 

[bruce linde]

all good... but you have not yet tried a thinner cord, correct?

 

[David M.]

all good... but you have not yet tried a thinner cord, correct?

Bruce
Due to arrive tomorrow from Amazon. That should make for more interesting information to share. Those "S" hooks were loosing me 1/2 day; so yours was a great idea. That and maybe I had not originally wound up as high as I could, not knowing how important it would be.
David

 

[Willie X]

I think you have used 'mm' where 'cm' should be ...

It's normal for the weights to drop around one or two inches below the pendulum's tip.

If you are building a case, I would shoot for 8 days plus a little for good measure.
Just measure the drop for exactly 4 days and double it, plus an inch for good measure.

BYW, it's best if the weights rest on the floor with one turn left on the drum.

There's a load of comprising in the world of clock case construction.

Willie X

 

[David M.]

I think you have used 'mm' where 'cm' should be ...

It's normal for the weights to drop around one or two inches below the pendulum's tip.

If you are building a case, I would shoot for 8 days plus a little for good measure.
Just measure the drop for exactly 4 days and double it, plus an inch for good measure.

BYW, it's best if the weights rest on the floor with one turn left on the drum.

There's a load of comprising in the world of clock case construction.

Willie X

Thanks Willie
I'm better with grams and liters. Use them in my work every day. You bet I'll build a bit more into the case.
David

 

[David M.]

Per advice from Willie X, I'm going to run this test for 4 days, then multiply my drop by two. That will give me my 8 day target. I've looked at fatter, shorter weights which would give me a shorter overall drop, but set me back about $100. That's fine, but I like the look of my current weights, and they might be too close to one another and the pendulum bob.
Please see the pics. Since I'm designing and building this case, why could I not take this direction?
I see no obstructions for the line not to go up at that angle, but will build it into my test stand first as a trial. I think it looks cool Just guessing it would be an easy build, and easily give me 8+ days.
I'm still going to try the thinner line for the weights to see what that will do.
Your input if you could.

 

[Willie X]

Well, that set-up is not compounded and will require twice the weight drop and about half the amount of weight.

Also, the exit angles of the lines from the drums will probably require different angles, or at least one extra guide roller/pulley.

Also, that little dial is gonna look lonely in a case so wide ...

I would suggest building a simple scale model, or at least a half scale drawing.

Willie X

 

[David M.]

Well, that set-up is not compounded and will require twice the weight drop and about half the amount of weight.

Also, the exit angles of the lines from the drums will probably require different angles, or at least one extra guide roller/pulley.

Also, that little dial is gonna look lonely in a case so wide ...

I would suggest building a simple scale model, or at least a half scale drawing.

Willie X

Thanks Willie X
Seemed almost too perfect.
David

 

[David M.]

Hello All
Well, after a week with thinner weight line (half the thickness of my original line) I can report that the thinner line makes little or no difference in daily or overall distance of drop. I am pretty happy with where the weights end up at the beginning of the 8th day. So now I get to complete my case design and build. Thanks to all who reached out to help and chime in.
The attached pic shows where the weights are on the morning of the 8th day. I'll be rewinding on the 7th day.
David

 

[David M.]

Case is finally done. I intentionally wanted to avoid the ornate conventional cases of that era. I drew up several design ideas and ended up going with this one. Its made from Cherry with mahogany accents including shop-made mahogany hinges. The mechanism was purchased on E-Bay. No pendulum, no weights or pulleys, no case.
I bought the beveled glass panels and did the lead came work myself.
Thank you to all who helped me work out the pendulum length as well as the weights.
David