You may be right but I am restoring a clock which could potentially survive a further few centuries. Differences in the composition of the alloys have a tendency to show up over time. I want to get it right, and the value and rarity of the clock means that I don't need to compromise if I don't have to.

I made the part on the right in my previously posted picture (a clock wheel) from some cast yellow brass sheet sold specifically for antique clock restoration. I hammered it first to work harden before machining it using a wax chuck. I will be cutting the teeth using a fly cutter (the tooth shape on old clocks is pretty non-standard) before crossing it out. I included it its he pic as an example of the colour I need to match,

The piece on the left is the backcock from which the pendulum will be suspended. I agree that it, and all the other castings (see below) could be made in a different way – either cutting from the solid or fabricating by silver soldering pieces of sheet, but casting is the more authentic method and since I may wish to do this again in future i am keen to find a reliable supplier whom I can trust. The castings in the pic look pretty rough but that is because I made a terrible job of casting the waxes from my patterns and not the fault of the foundry who, apart from using the wrong metal, did a good job.

Edited By Nigel Watts on 18/12/2019 07:36:08

Phil – what a good question, and one horologists can debate for hours on end!

My clock – a London made spring-driven clock by a recognised maker dating from 1710 – started off life with not only an hour strike, but also a quarter repeat mechanism (on the pull of a string) and an alarm. These clocks would originally have been carried around the house by a servant and placed next to the bed at night. In more recent times, such clocks ceased to be carried about and just sat on tables or mantlepieces and the quarter repeats and alarms fell out of use. Furthermore, the original verge escapements, which were so robust they could survive the moving about, also tended to get replaced with more accurate but more delicate anchor escapements. My clock, which I bought at a public auction, is missing its quarter repeat and alarm and has an anchor conversion.

Current feeling and practice amongst connoisseurs and restorers is that reconversion to verge and reinstatement of missing mechanisms is acceptable practice, as is trying to make the parts look authentic, including using the right colour brass (in fact not using the right brass is frowned upon). These clocks (mine included) don't just have ornate faces; the backplate and even some of the interior parts are ornately engraved, so its a bit like restoring a painting – all has to look right and blend in. I don't intend to sell the clock but in this internet age any knowlegable buyer would quickly be able to discover the auction catalogue listing and associated images of the clock in its unrestored state and deduce what had been done to it.

One thing I am being scrupulous about is making sure everything is reversible. This means using only the existing holes in the plates. Where these are threaded (and there were no standards in 1710), I will be making bespoke screws to fit. The only holes I will need to drill are where some original holes were plugged during the conversion to anchor. The main dilemma is to what extent should any remaining unused holes (mainly those drilled to fit the anchor mechanism) be plugged.

Just had a reply from my caster:

"I have never seen it come out pink before and i have been doing this a very long time. The only time you get a pink colour is silver solder flux will turn it pink but this comes off when the flux is cleaned off. A pink colour is the colour of Bronze and not the dark brown that people think of Bronze we do not cast much of that. Lost wax brass is just a less yellow colour we can sand cast the clockmakers yellow brass but as i said it gives off a lot of fumes so we cast that when we have enough orders to make up a load and do it in the evening when everyone has gone home the smoke that comes out is unbelievable. If you wanted to do that we would need patterns 4% larger and the casting would need a lot more work and may have some gas holes in it."

I have asked my caster to provide me with a specification of the brass he used and that of the yellow clock brass so that I can understand the differences and talk specifics rather than generalities. He seems to have failed to understand the point that there is a spectrum of colour for different brass alloys, with those higher in copper being pinker and those higher in zinc being yellower. Fastidious clock restorers only want the yellower brass.