Turret clock

[Michael Smith 15Participant @michaelsmith15]

I have recently acquired a large pendulum from a turret clock . It is of wooden construction with a bob of cast iron that weighs about 20 lbs and is 64 inches long.

It is very nicely made and I would date it some time between 1880 ad 1920 unfortunately the clock is long gone. I would like to build a clock to incorporate it into with a gravity escapement . I don't really want to start from scratch , does anyone know of any drawings that might exist for a clock of this size as all my searches draw a blank . I would use plasma cut gears and fabricated frame .

Size is not a problem as I have access to cnc plasma cutting up to 20mm on a 2 meter square table and can handle up to 4 foot diameter on my lathe

I have built several of J Wildings clocks including his turret clock with a grasshopper escapement.

Any ideas on escapement design and gear sizes and ratios would be much apperciated

[Michael Smith 15Participant @michaelsmith15]

[Michael GilliganParticipant @michaelgilligan61133]

Michael … I suggest you grab this : **LINK**

https://archive.org/details/towerclockhowtom00ferso/mode/2up

[ PDF download available ]

I dates back to 1903, and is superb !

MichaelG.

[Michael Smith 15Participant @michaelsmith15]

Thanks for the reply , I have ordered a copy of the book. I find it difficult to read these documents on line and much prefer to hard copy in front of me I found a reprint available for about £10.00 delivered Thanks Mike

[ChrisLHParticipant @chrislh]

There is a very nice miniature version of the Big Ben gravity movement in the church tower in Askrigg, N Yorks. Made by Potts of Leeds. I have no other info. unfortunately.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the reference, Chris

Must stop-off there next time we are heading NorthEast

**LINK**

https://www.britainexpress.com/counties/yorkshire/churches/askrigg-st-oswald.htm

… includes no technical details, but does have an interesting photo of the old dial face.

MichaelG.

.

Edit: … which makes me wonder a little about the pictures here:

https://www.richmondshiretoday.co.uk/askrigg-time-not-chime-yet/

Edited By Michael Gilligan on 03/12/2021 11:55:56

[Peter Cook 6Participant @petercook6]

Michael, as part of a plan to make a model of the church clock which I wind twice each week, I have been documenting the clock. You can see my original posting with a couple of pictures at

A Tower Clock project | Model Engineer (model-engineer.co.uk)

Although this is a Pinwheel escapement rather than gravity arm if it is of use, the details of the clock gearing are

Time train            Teeth Rotation
Great wheel Teeth 120 180 Rotates every 3 hours
1st Pinion Pins        10
2nd Wheel Teeth     90 15 Rotates in 15 Minutes
2nd Pinion Pins         8
Escape Wheel Pins 35  2.29 period secs
Escape wheel rotates   80.00 Seconds
                                     3150.00 BPH
Pendulum Length 1.30 Metres

Drive Wheel for Minutes 40    60 Rotates once per hour
Bevel Gear on Minute     45

Chime train
Great Wheel        240 Rotates once per 2 Hours
1st Pinion               10
2nd Wheel           120
2nd Fly Pinion       10

Strike train
Great Wheel       240 One rev = 12 strikes
1st Pinion             20 One rev per strike
2nd Wheel         120
2nd (Fly) Pinion   10 12 revs/strike?
Count wheel       78

I have a spreadsheet that computes the pendulum length from the gear counts in the time chain.

Fiddling with it suggest that if you used these numbers and reduced the number of pins in the escape wheel to 32, then

Escape Wheel Pins 32    2.50 period secs
Escape wheel rotates in   80.00 Seconds
                                        2880 BPH
Pendulum Length 1.55 Metres 

which is about 61" effective length – so possibly OK for your pendulum.

In a posting on the other thread Michael pointed me to https://richard.burtons.org/2014/11/28/restoring-a-j-smith-and-sons-derby-turret-clock/ which is a restoration of a very similar Smiths of Derby clock, but that one does have a gravity escapement.

Hope this is of use.

Edited By Peter Cook 6 on 03/12/2021 14:50:43

[Michael Smith 15Participant @michaelsmith15]

Peter thank you for that information ,it will give me much food for thought it is exactly the information I was looking for. I shall start to think about wheel sizes etc .

Several years ago I built a green oak tower in my garden which is 25 feet tall and 12 feet square to house a copy of the clepsydra that is at Killruddery **LINK** So I will use my pendulum as part of a clock to keep it company Thanks Mike

[Peter Cook 6Participant @petercook6]

Look forward to following the build.

For information most of the wheels on my the church clock seem to be about 10DP. The Great wheel on the time train and the 2nd Wheels on chime and strike are about 300mm diameter. The great wheels on Chime and strike are about 400mm diameter. The time second wheel is 215mm diameter. All the pinions are lantern pinions except the 40 tooth driven pinion for the minute arbour and that contains the friction clutch for hand setting.

The clock frame is 1600m wide and 575mm front to back.

All dimensions are approximate – it's fairly hard to do accurate measurements on a running clock.

If you want any specific details please send me a PM and I will try to help.

[Author]

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