Suggested basic clock design please

[modeng2000Participant @modeng2000]

John, Yes I have decided to have a go at the Wilding battery clock. As you say a contact-less approach would be better and easily possible these days. I have it in mind how to research how to impulse pendulum after having read the book.

John

[John HaineParticipant @johnhaine32865]

John, I bought some inductive proximity switches like the ones shown in this eBay ad: item No. 397247078650.  I haven’t used them “in anger” yet but they look useful for pendulum sensing.  Lots of similar devices around for not much money.  Advantage is that you don’t need a permanent magnet as a Hall device would and they are immune to light.

[modeng2000Participant @modeng2000]

I have used a basic hall effect semiconductor to sense lathe spindle rpm but this did require a magnet on the spindle.

One consideration is the power supply required, 10v is more than I hope to use but the absence of a magnet is an advantage. I wonder if there is a lower operating voltage version?

John

 

[modeng2000Participant @modeng2000]

I have found this one, Makertronics Inductive Proximity Sensor SN04-NO, 5-30v dc NPN

John

[modeng2000Participant @modeng2000]

I guess it is not surprising that I am looking for information.

John Wilding said that one size of wheel cutter is suitable but there are several sizes in a set. He used 48dp but doesn’t say which of the tooth counts is most suitable. I’m inclined to go for a higher number but am undecided as to how to make my mind up.

John

[John HaineParticipant @johnhaine32865]

I have several times been left confused by reading John Wilding…

[modeng2000]

On modeng2000 Said:

[…] but there are several sizes in a set. He used 48dp but doesn’t say which of the tooth counts is most suitable. I’m inclined to go for a higher number but am undecided as to how to make my mind up.

John

Only for Involute

This is only a guess, since I have not read the book: I think you might want 0.525 module Cycloidal

Wheel Cutter

MichaelG.

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[Michael GilliganParticipant @michaelgilligan61133]

Q.E.D.

From the originalarticles, and therfore presumably the book :

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MichaelG.

[BazyleParticipant @bazyle]

He is meaning one tooth size. Check any other manufactured clocks you have and you may well see that the motion work has a courser tooth.
I think if you followed his series of books, from beginners onwards he changed module for the next more difficult then you would have two different sizes for your third clock and gradually build a collection.

[John HaineParticipant @johnhaine32865]

Since he’s quoting the module to microns note that 25.4/48 = 0.5291666667. Not that it will make any practical difference.

[modeng2000Participant @modeng2000]

Thank you all, I understand one tooth size being used throughout the clock, this was the same for the Jubilee clock by John Wilding.

However my concern is which of the cutters in the range would be best, there are eight to choose from. Is it that any of them would suffice? Also I’m aware that involute cutters are not really for clocks but they do seem to be acceptable in this application.

So should I choose a cutter for a high tooth count or doesn’t it matter?

John

[modeng2000Participant @modeng2000]

Michael, that chapter is in the book but as you will realise it doesn’t help me to make the decision.

John

[John HaineParticipant @johnhaine32865]

Cycloidal teeth are supposed to be better in the going train which usually has high step up ratios (though evidence is scarce). This clock just has motion work stepping down the ratchet wheel to the hands, for which involute are better anyway.  The implication of what he writes is that a cutter for 48 teeth and 48 DP is suitable. It’s quite easy to make single tooth cutters, I’ll post a link.

[John HaineParticipant @johnhaine32865]

https://mikesworkshop.weebly.com/making-gear-cutters.html

Describes a way to make cutters. Elsewhere on the site is a description of how to design them.  Very interesting site generally with lots of good ideas.

[modeng2000Participant @modeng2000]

Thanks John, I will read mikesworkshop, any info is useful at this stage of making my mind up.

Having written a technical description or two describing equipment I realise it is very easy to say what is in your mind without explaining the finer details. The designer just knows what is going on in their head but sometimes does not put their ideas completely into the description.

I remember making a single point cutter for the Jubilee clock.

John

 

[modeng2000]

On modeng2000 Said:

Michael, that chapter is in the book but as you will realise it doesn’t help me to make the decision.

John

There  is no decision to make, unless you are modifying the design !

Wilding uses a 0.525 Module, Cycloidal cutter … and so should you.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Go Compare … with the tooth-shape of any version of a 48DP Involute that you care to choose.

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Feel free to re-design the clock my all means …

MichaelG.

[modeng2000Participant @modeng2000]

Michael, at last I think I understand. About time do I hear?

Thank you all for your help and patience.

John

[Michael Gilligan]

On Michael Gilligan Said:

Go Compare … with the tooth-shape of any version of a 48DP Involute that you care to choose.

.

.

Feel free to re-design the clock my all means …

MichaelG.

Michael.

I think that I’d be redesigning the teeth of those two examples in your picture to make them a little less ‘drunk’. 😉

 

Martin.

[Michael GilliganParticipant @michaelgilligan61133]

Not my picture, of course … but John Wilding’s

I thought the photo-credit was there by implication.

MichaelG.

[BazyleParticipant @bazyle]

The tooth distortion is photographic parallax not a defect.

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