John Wilding Congreve Clock

[Barry BParticipant @barryb]

Hi

Been a while since I posted. I got John Wilding’s congreve construction book and really fancy giving it ago. I repair clocks for my own pleasure and make the odd piece as required. I have a watchmakers lathe and a model engineering lathe plus all the usual workshop equipment. Reading through the book I see nothing that I find too daunting although I have never cut gears it will be a learning experience. The plans are all dimensioned imperial which makes it difficult as living in France everything is metric. So my first question has anybody built the clock converting the measurement to metric? My thoughts would be to convert the frame to metric but keep the clock gears imperial to maintain the integrity of the design although generally the play in clock mechanisms is such that I can’t see conversion would present a problem. I am sure that I will have many questions as I progress and would welcome any hints or tips that forum members can give me.

Bonne année à tous

Barry

[Martin KyteParticipant @martinkyte99762]

Why does making things dimensioned in imperial present problems. If the plans say one inch just make the part 25.4 mm. You will have less trouble than trying to convert  everything to metric first.

Brass sheet is generally only available in mm thicknesses these days so the nearest equivalent will do but keep all other dimensions the same.

I’ve done a few Wilding designs but not the Congreve although I had a mate who built one. The critical bit is getting the ball to turn around smoothly at the end of each zig or zag so as not to loose too much energy.

It’s an interesting clock but don’t expect good timekeeping as a precision timepiece it certainly isn’t. Good fun to watch though.

Go for it.

regards Martin

[Martin Kyte]

On Martin Kyte Said:

Why does making things dimensioned in imperial present problems. If the plans say one inch just make the part 25.4 mm. You will have less trouble than trying to convert  everything to metric first.

Brass sheet is generally only available in mm thicknesses these days so the nearest equivalent will do but keep all other dimensions the same.

…
Go for it.

regards Martin

As I understand it this clock calls for many parts to be made from Imperial stock.  For example, wheels (gears) cut from 1/16″ Brass plate, that align to mesh with other gears.

1/16″ is a little under 1.6mm, so 1.5mm Metric plate is probably close enough with minor adjustments.   But is the same true of parts intended to be made from 1/8″, 3/16″ , 1/4″ and larger Imperial plate, angle and rod?

I’ve often substituted 6mm for 1/4″ but occasionally find metric rod is uncomfortably small for some applications.  Likewise, 10mm rod usually substitutes well enough for 3/8″ but occasionally has to be turned down because it fouls something else.

I guess the answer depends on how much dimensional flexibility there is in the build.  Adapting a  tightly packed design from Imperial stock to Metric (or vice versa) might require a lot of tweaking.

Anyone built a Congreve from metric stock?  Was it easy or difficult?

Dave

 

 

[Martin KyteParticipant @martinkyte99762]

<p style=”text-align: left;”>I did say use the closest available metric brass sheet. Generally clock wheels don’t need to be bang on thickness. The only exception I ever came across is the escape wheel and large pinion on Wildings large great wheel clock which due to the extra inertia resulting from their large diameters (the pinion is more of a wheel) using thicker material prevents the clock from running successfully. It’s easy enough to skim wheels down to thickness. You certainly want to retain the exact dimensions for the ball racetrack plate to keep the track length the same and also the mass of the plate.</p>
regards Martin

[Barry BParticipant @barryb]

Hi
Thanks Martin and Dave for the advice and encouragement. I will be starting with the going train as this represents the biggest challenge for me in gear cutting. I don’t think the thickness of the wheels will cause a problem as there will be ample adjustment on the arbors plus running in lantern pinions gives plenty of “slack”. The diameter will be important as will the gear cutting, these I will keep imperial as the calculations were done in inches as was the table. I will be using metric threads as BA threads are not easy to find in France and getting them from UK is real hassle. Anyway time to order some material and gear cutting tools.
Barry

[Russell EberhardtParticipant @russelleberhardt48058]

Yes, BA screws are as rare as rocking horse droppings in France.

I don’t know if you have done any clock work – I don’t want to teach granny to suck eggs but old drawings usually specify “engraving brass” for the wheels.  You won’t find that in France but it is just 2% lead free cutting brass.  You can buy it in small quantities from http://www.tartaix.com in Paris, look for “Uz39 Ecroui”

Russell

[Barry BParticipant @barryb]

Hi Russell
I repair clocks and watches as a hobby but other a couple of wooden clock kits this will be my first build from scratch. Thanks for the tip for the material source. I have been doing a bit of reading about gear cutting and how I can manage it on my lathe, there are a lot of good videos on the subject. I don’t see any problems with the other turned parts as I have been using my lathe for the last 10 years or so. The plates I will cut myself or depending on cost get them laser cut.
Barry

[Martin KyteParticipant @martinkyte99762]

Just to avoid confusion to non clockmakers reading this thread that’s free cutting 2% Leaded Brass. Know, as has been stated, engraving brass, compo brass or half hard brass.

regards Martin

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