Advice on making a BIG CLOCK for a clock tower.

MalWelsh

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Hi everyone.:wavinghi: Thanks for having me on your site. I am hoping to be a first time clock builder.
I want to build a clock for a clock-tower. The face diameter will be 1200mm.
I have downloaded a copy of Brian Law's clock no.1 which I hope to use as a basis for my design.
I also have a 3d model from Grabcad based on the same clock.
As the original clock is for a 300mm face, I want to enlarge the whole mechanism about 4 times if possible.
Are there any design problems I will need to consider? I would appreciate your thoughts.
Many thanks.

Ps. I went to a book fair on the weekend and picked up a very interesting book, "Clocks & Clock repairing," by Eric Smith.
If I am successful with this project, I will be glad to share drawings, models,photos, etc.
 
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First, welcome to the Hobby-Machinist! I am sure you will find many answers to your questions here.

Your clock tower project sounds like a tall order! (Sorry about the pun!) In reality it does sound like it might not be the place to be starting out making clocks, I would hope that you would build a few smaller ones first. Even when built exactly to plan, clocks can be fickle critters, and building some smaller ones first would help you learn the basics. I am not trying to discourage you, nor am I saying that a large clock as a first project cannot be done. I am simply saying that it may not be the best place to start. A large clock with a fifty inch dial would be quite a project to say the least, and the problems one could encounter would be just as large.

Clock design is also a science of its own. Enlarging an existing plan would need to be done with some forethought and care, especially a wooden design like the one you are talking about. I would proceed with caution and learn all that I can before proceeding with some small clocks as first projects. They would be a good place to start.

I only know some of the basics about clocks, and I am no expert by any means. Perhaps one of the other people here that is better versed in the subject will respond to your query. Another option is to contact some current clock designers and builders such as Brian Law and see what advice they may be able to give.
 
I suggest you to make a 300mm clock as prototype.
Generally clocks, if seen as motors, have a good torque, and probably the 300mm one can be "beefy" enough to move 1200 mm hands, if you make them very light using thin aluminium or even composite materials.
With an "enlarged" clock you also risk to run out of working space on your tools: the clearance required to machine gears having a diameter of a metre or so requires big lathes and big mills (and even big CNC machines).
 
First, welcome to the Hobby-Machinist! I am sure you will find many answers to your questions here.

Your clock tower project sounds like a tall order! (Sorry about the pun!) In reality it does sound like it might not be the place to be starting out making clocks, I would hope that you would build a few smaller ones first. Even when built exactly to plan, clocks can be fickle critters, and building some smaller ones first would help you learn the basics. I am not trying to discourage you, nor am I saying that a large clock as a first project cannot be done. I am simply saying that it may not be the best place to start. A large clock with a fifty inch dial would be quite a project to say the least, and the problems one could encounter would be just as large.

Clock design is also a science of its own. Enlarging an existing plan would need to be done with some forethought and care, especially a wooden design like the one you are talking about. I would proceed with caution and learn all that I can before proceeding with some small clocks as first projects. They would be a good place to start.

I only know some of the basics about clocks, and I am no expert by any means. Perhaps one of the other people here that is better versed in the subject will respond to your query. Another option is to contact some current clock designers and builders such as Brian Law and see what advice they may be able to give.
Thanks for the advice Wermy. I will give it some thought.I don't want to make it of wood. I am thinking of laser-cutting aluminium gears at this stage, but I am open to suggestions.
Regards, Mal
 
I suggest you to make a 300mm clock as prototype.
Generally clocks, if seen as motors, have a good torque, and probably the 300mm one can be "beefy" enough to move 1200 mm hands, if you make them very light using thin aluminium or even composite materials.
With an "enlarged" clock you also risk to run out of working space on your tools: the clearance required to machine gears having a diameter of a metre or so requires big lathes and big mills (and even big CNC machines).
Thanks Marco. I might try your idea with the 300mm driving the larger hands as a prototype.
I am planning to get the gears laser cut from aluminium sheet at a local factory, so that should resolve most of the clearance issues. I also have a friend with an engineering shop who has lots of large macsons, some with removable bed sections for large diameter turning. He even has an old vertical lathe with a face of about 4'.Should be fun!['A friend in need is a friend indeed!]

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I think build a big one! full size will be less fiddly, and for more torque, just add more weights!, they have been built since the mid 1300's, and I dare say you will have better equipment than they had then. Good Luck!

http://en.wikipedia.org/wiki/Salisbury_cathedral_clock

Phil
UK.
Thanks Phil! I really appreciate your positive comments, and I have to agree with your sentiments.
I was interested to to look up your link to the Salisbury clock as that was what provided the inspiration for this idea in the first place.
Regards, Mal.
Ps. Love the quote!
 
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BTW, if your clock must be seen just from a distance you can consider to make the hands not totally full, but with small holes and cuts to reduce both the weight and the wind influence, maybe with a pattern like filigree.
I find the hands of this Breguet watch particularly elegant, and they also will fit nicely on a tower clock:
http://www.hodinkee.com/blog/hands-...que-exclusive-minute-repeater-live-pics-video
(the price of that watch is around $200,000, so don't drool too much for it :lmao:)
 
If you have all of the horology laws/sciences understood, have the machining knowledge and tooling to fabricate large clock parts, finesse, finances and unlimited time. And there was no order to the job resume requirements just mention. But, if you have all of them, then, “Get’er Done”...Good Luck
 
BTW, if your clock must be seen just from a distance you can consider to make the hands not totally full, but with small holes and cuts to reduce both the weight and the wind influence, maybe with a pattern like filigree.
I find the hands of this Breguet watch particularly elegant, and they also will fit nicely on a tower clock:
http://www.hodinkee.com/blog/hands-...que-exclusive-minute-repeater-live-pics-video
(the price of that watch is around $200,000, so don't drool too much for it :lmao:)[Thanks Marco. I enjoyed the link! It really is a beautiful timepiece. Regards, Mal]
 
I am building a large clock out of brass and S/S free maching. I would be very happy to

help in any way and I would love to see the details. Patrick

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Correction "machining"
Patrick
 
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