Basic Clock Design

That is not unique to weight driven clocks John and is usually caused by over lubricating. The only fault I have come across that is only found on weight driven clocks is a result of insufficient rigidity causing the weight to swing slightly in tune with the pendulum when the drop is the same as the pendulum length thus removing energy from the pendulum.

Russell.

What I mentioned to them Russel was that there didn't seem to be a best time regulation setting available on the pendulum setings, It's hard to explain but say it was running fast and it's adjusted to slow it down. With fine adjustments it gets better and better and then goes the other way with a bit of a jump. They said weights and if I undid the weight canisters I would probably find that the weights inside allow adjustment. They might not even be the original weights.

The clock probably dated from around 1900 most likely before so has had a lot of use. It's been on the back burner for some time as far as I am concerned as I haven't really got sufficient space to get the movement out and check the escapement etc. It needs that really as the pendulum throw looks to be adjustable. Given a general look there was no signs of dust or too much oil etc.

Things are looking better on my workshop front - we've found a builder but my work area wont get sorted until the weather warms up.

Oh and in order to improve that wife gets a new kitchen.

John

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Edited By Ajohnw on 15/04/2016 17:06:06

Better is to adjust the running from slow to fast, that way the pendulum bob movement is more controlled.

Niko.

I went both ways numerous times Niko. It will be interesting to see if the tat shop was correct when I get round to it.

John

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The easiest way to set the regulation on a clock with a reasonable pendulum length is to have a platform about half way up the pendulum rod. The adjustment on the pendulum bob is then made to set it to run slightly slow and small weights are added to the platform to raise the centre of gravity of the complete pendulum to speed it up by very fine amounts.

Russell.

That I think is one of the ways Peter Heimenn suggests for the clocks he deals with in his book Russel which he reckons will hold 2sec per week. The book is called "Regulator Clock Construction". He gives 2 designs in it. Personally I think it's pretty good value compared with some.

My challenge is this beast.

I don't anticipate any problem with the mechanism but the 2 missing bits will be a challenge. The worst one being getting the colour of the "rose" shaped part correct. The tiny bit of missing woodwork may not be such a problem. The missing rose can be made from a plaster casting but getting the colour to match is another matter.

We're not minimalists here by the way in case some one doesn't notice.

John

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John,

You are probably aware; but I should mention [for the benefit of any novices reading his hread] that a 'proper' Regulator differs greatly, in construction and performance, from the typical 'Vienna Regulator' that you are having trouble with ... 'though they do both have their place.

Now:

When I worked on my Mother's Vienna, it ran beautifully in my test stand, but was very troublesome when returned to her. ... The reason turned-out to be that the glue holding the case together was failing ... The flexing of the case robs energy from the pendulum.

MichaelG.

True Michael but the usual term for them is Vienna Regulator. They can keep good time as well. The book I mentioned contains two regulator designs. Much plainer animals although the month going one does show the movement fairly well.

An antique dealer sold it to me because of the 2 missing parts as small as they are at a very reasonable price all things considered. Having just checked ebay prices I am even more pleased with that aspect as it is basically sound.

We have another much smaller one in the hall that was very cheap - the top decorations missing. That one really should go in the bin as even with something suitable on top it just doesn't match the rest of the clock.

John

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John, you can buy the rosettes for "Vienna" clocks in various sizes from Meadows and Passmore. As it's the middle one missing you could go a size up if they don't have the exact size you need.

Russell.

There isn't much room around them Russel. I have seen various sizes at the odd clock fair I go to but the colour of the "new" ones is hopeless and would never match. The seller pointed out that it would be a problem, Easy to make a replica but he reckoned I would never match the colour. The alternative would be to put something entirely different there but I don't think that would work in the case. It didn't on the one in the hall but that is a very cheap old clock. The colours don't match and the addition looks cheaper than the clock.

Following Michael's comments I had a look around at true regulators. One thing that surprised me was that they date from 1800 plus or minus rather a lot and scarcely any example photo's about at all. Just shots of the face showing the separate hour, mins and seconds dials. The mention of this one earlier in the thread has fascinated me

2 aspects. The general construction and the use of dural. Interesting to note that it uses an electric remontoire that winds every 30 sec. That seems to be done by the wheel that looks like it's the escapement but that seems to be behind it.

Also serves as a shot of a real regulator but the hour dial is rather unusual.

John

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Edited By Ajohnw on 17/04/2016 13:31:09

Well that's Burgess' Clock B at the Greenwich Observatory, hardly 19th century as it was finished in 2013! Has been running for 2 years in the Clock Workshop and has never been more than a second adrift from exact time. It demonstrates what Harrison's grasshopper escapement is capable of when properly implemented. There have been two seminars held at the RGO on the clock and I had the chance to have a close up look at the second. However it isn't perhaps a "basic clock design"!

I seem to remember the electric drive to the remontoire was really simple - no clever escapement. Are you looking at the right thing - I think the remontoire weight is brass lump at bottom left of picture.

The ones I bought from M & P for the Vienna clock I restored came unfinished and I stained and varnished them to match. I agree that matching staining is not easy but it can be done.

Russell.

Jack, John, the brass weight drives the great wheel through (IIRC) a differential arrangement so it can be lifted by the winding motor every 20 minutes (this is from Frodsham's website). The remontoire is essentially a spring arrangement behind the escape wheel (at the top of the clock) which is itself rewound every 30 seconds. The main rerason for the remontoire here is to keep the drive torque to the 'scape wheel, and hence the pendulum impulse, as constant as possible and isolated from variations introduced by inaccuracies and stiction in the train.

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**LINK**

MichaelG.

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Edit: This page may also be of interest

... 'though we have strayed rather a long way from 'basic clock'

Edited By Michael Gilligan on 17/04/2016 18:02:47

Books by John Wilding have all you need to know about the basic clock designs,his straight foreward approach to his text is easy to follow.I started out by reading a book of his from the library and built two astronomical regulators.The first to my own design to take account of my lack of equipment and knowledge.I had to fix the wheel sizes on a needle file for tooth and space,I set out the teeth with a disc of paper glued to the blank and carefuly set out the divisions,filed out the teeth and with with a pattern filed the crests.wooden pendulem rod and lead weight and bob.They needed to be heavy to overcome any discrepencies.Why I am saying this is that there is nothing wrong with your design and they don't have to be perfect to work ,this clock when finished kept time after much regulation to two seconds a week.My second clock [by now I was tooled]was a near copy of a Riefler regulator and has a 2degree of arc on the pendulem and is driven by a 1.5lb weight .Don't get bogged down with to many technicalities get stuck in.

Frank

I thought from comment in the thread that it was obviously not an 18 - 19 century design. The method of CONSTRUCTING it is interesting and personally I think the use of dural is too. The mechanisms are not really related to that. Trying to find out how it works is another matter. I take the hefty weight as relating to the unusual hour dial. Also there are other pictures about and some show the other wheel behind what appears to be the escapement wheel. There are is an interesting series of 13 video's on youtube of some one building a replica of one of Harrison's clocks which suggest a simple weight isn't used as well.

**LINK**

John

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Edited By Ajohnw on 17/04/2016 19:35:12

The weight drives the hour wheel, which drives the minute wheel, which drives the remontoire input, which drives the scape wheel through a spring mechanism. Actually it's quite a simple clock apart from the grasshopper escapement. The dural is I think mainly the dials and large wheels, the backplate is a massive 1 inch thick mild steel plate and the cocks and bridges also steel IIRC. The construction was described at the seminars by a man from Frodshams but for some reason the RGO has chosen not to publish the slides. It's a big clock too, must be a metre and a half tall.

Edited By John Haine on 17/04/2016 22:49:27

Frank: thank you.

I am currently redrawing the design using 0.6 mod wheels and pinions instead of 1 mod. One result of this, without increasing the tooth count, is that I will need to make pinions with 10 leaves and an outside diameter of 6mm, another with 8 leaves and OD of 4.8mm. Are these realistic sizes for pinions or are they likely to be too weak?

Regards,

James.

Edited By James Alford on 17/04/2016 22:57:18

Well Thorntons sell pinion cutters down to 6 leaves for 0.6 mod so it should be no problem. Bear in mind though that the pinion cutters are different for each number of leaves and are rather expensive. The wheel cutter covers all numbers of teeth. It may be more economical to purchase lengths of pre-cut pinion rod and bore and cut to the required lengths.

Russell.