Basic Clock Design

Missing Eagles

Regarding ornamentation on Vienna Regulators, many were supplied originally with an eagle on the top plinth. At the outbreak of the war with Germany most households removed the eagle for obvious 'patriotic' reasons which is why there are a huge number of these clocks now with empty plinths. My grandfather actually stored his eagle away but as it was 'off the clock' for so long the colour is now slightly different.

Regarding the main part of this thread, go for lantern pinions.

regards Martin

No, that is not to weak but these smaller diameters are more critical, best is to do trail cuts first in brass until set-up is correct. I leave the blanke diameter a little oversized (0.2 mm) to make sure to get the full tooth profile. You will have to harden, polish and temper the pinion to get maximum strength. Niko.

Edited By James Alford on 18/04/2016 12:47:14

I was wrong. But, the motor driven weight could be a nice simple solution for Jame's clock.

Can the motor driving the brass weight be considered a form of remontoire or are there some conditions it doesn't meet in order to be considered one? e.g. does it have to be supplying power closer to the escapement?

Edited By jaCK Hobson on 18/04/2016 13:56:08

.

"a form of remontoire" ... I would say Yes

[Note: I did try to keep that broad definition when I mentioned it earlier]

A good recent example is included in John Reynolds' "new design of" Regulator which is being published in EiM and has been completed in HJ.

MichaelG.

.

P.S. ... Harrison did not have the luxury of electrical rewinding available to him ... but I'm sure he would have used it if he could !!

Edited By Michael Gilligan on 18/04/2016 14:48:48

While nosing around one the web I came across something that confused me so as this is basic clock question I may as well clarify it 'cause my assumption may be wrong which is

That a 1 second period pendulum with completely rotate a 60T escape wheel in 60 secs / 1min, ???

Not a so called seconds pendulum but one which is circa 248mm long.

John

-

John,

Have a look at the other recent clock thread ... particularly my post on 03-April

MichaelG.

LOL that thread doesn't help in places a 1 sec pendulum based on my sums which should be correct reckon that it will be circa 248mm long. I notice that you used the more correct term SECONDS and the s on the end infers a 2 sec pendulum which will be circa 1/2 a metre long and will tic tock at 1 sec intervals with tooth released by a "1/2 a tooth" on each tick and tock.

So a true 1 second period pendulum without the s on the end will need a 60T escape wheel to revolve once per min.

maths L= g*T/(2*pi)^2

If I have anything wrong please point out where. To be honest I never worried about it to date. I am pretty sure I have something wrong because my impression is that a seconds pendulum is circa 1m long.

John

-

I think at one time it was proposed to define the meter as the length of a pendulum with a half period of one second. That didn't stick but it isn't far off.

John,

It's confusing, but a long-established 'fact of life'

Physicists work with the [full cycle] period of a pendulum

Horologists work with the [half cycle] beat of a pendulum

MichaelG.

Edited By Michael Gilligan on 18/04/2016 19:23:04

Does a pendulum go tic as it swings to the left and toc on the right or the other way round? And is it reversed in the southern hemisphere? Perhaps some of our Australian forum members could confirm.

.

NO ... it's the escapement that makes the noises.

So working it out as I type a 4 sec period pendulum 1m long has a 2 sec beat so for each 2 sec interval the escape wheel advances by 1/2 a tooth. But if it did that a 30T wheel would take 60*2= 120 sec to revolve completely so I'd suspect that it actually advances a whole tooth. If it did that a hand attached to it would have 2 sec jumps and not indicate seconds really, just 2 second intervals. That still sounds wrong.

John

-

Edited By Ajohnw on 18/04/2016 20:34:27

.

As they chant in the Panto:

Oh no it doesn't

Nominal 1m pendulum has a period of 2s and a 1s beat.

... Try it with a 'plumb line'

MichaelG.

Just goes to show that the web and some books need treating with some caution Michael. I should have transposed the usual formulae myself. You could have posted something like this

Which now makes more sense with 1/2 tooth advance per tic and toc swing as 30x2x1 is 60 sec.and 1 sec tics on the hand. The problem with the usual escapement information is that what is actually happening isn't really mentioned at all - just angles, angles and yet more angles.

John

-

John,

If you want a reliable book ... try Edmund Beckett [Baron Grimthorpe]:

A Rudimentary Treatise on Clocks and Watches and Bells

MichaelG.

Edited By Michael Gilligan on 18/04/2016 21:50:31

Apologies Michael,

But I dont think the above book fits in with 'basic clock design', and many chapters of that book especially relating to bells have been shown to be rubbish! I was in charge of a Church clock with the Grimthorpe escapement for many years and very well it performed, though it is hardly what I would regard as a beginner's type for clock design!

Although Claude Reeve described some rather complicated clocks in ME many years ago, his easy descriptions are worthy of study and are applicable to much simpler clocks and cannot be bettered IMHO, plus his descriptions of the fundamentals. I much prefer them to John Wilding.

Cheers,

Julian

.

Julian,

I was simply trying to point John to a reliable [and zero cost] source of information on the mechanics of Clocks ... I canmot comment with any authority regarding his information on Bells.

MichaelG.

Edited By Michael Gilligan on 18/04/2016 22:08:12

**LINK**

Not zero cost, but a wonderful book on mechanical horology, highly recommended.

One called The Modern Clock is probably better MIchael, from the same source.

Anyway you may have gathered the bit I hadn't understood but that's largely down to the web.

John

-