Clock Project

[pilotingpete]

Hello All,

I've been contemplating designing/building a clock movement for some time now. And despite a fair amount of reading, I must admit I don't have all the answers.

Thus far I have been able to work up the attached spreadsheet for the going train. When working out the ratios I wanted to keep with a single module, and common pinion leaf number to keep cutter cost down. I believe I will end up needing a cock for the intermediate wheel due to its neighbours diameters.

I am wondering if anyone has feedback on the selected ratios shown?

Also, when manufacturing a clock from scratch, and with known module cutters, would one still use a depthing tool for layout or would you place the bushing at the theoretical ideal location instead.

Thanks

 

[John MacArthur]

Pete - you would definitely do best with a depthing tool. Once I get the wheel/pinion pair depthed correctly, I measure the inside and outside arbor distances, and divide by two. Then you know the exact center distance. This is called "field verify all dimensions" on blueprints and such. I then draw circles in CAD of each distance, and the intersection of the two circles for each pinion/wheel pair will give you coordinates, which you can then drill. This will usually vary somewhat from the theoretical. I assume you have a DRO on your mill, or you wouldn't have mentioned "theoretical ideal location". Good luck, and keep us posted. BTW, the answers don't all come from reading books, they come from trial and error. I have bushels of mistakes.
Johnny

 

[pilotingpete]

Pete - you would definitely do best with a depthing tool. Once I get the wheel/pinion pair depthed correctly, I measure the inside and outside arbor distances, and divide by two. Then you know the exact center distance. This is called "field verify all dimensions" on blueprints and such. I then draw circles in CAD of each distance, and the intersection of the two circles for each pinion/wheel pair will give you coordinates, which you can then drill. This will usually vary somewhat from the theoretical. I assume you have a DRO on your mill, or you wouldn't have mentioned "theoretical ideal location". Good luck, and keep us posted. BTW, the answers don't all come from reading books, they come from trial and error. I have bushels of mistakes.
Johnny

Thanks, Johnny. That is an interesting idea to use the depthing tool in that manner - I hadn't considered that.

 

[Hessel Oosten]

Hi Johnny,

I'm so sorry, but I did not understand the procedure.
The depthing is clear of course.
This procedure gives -one- right distance between the 2 centers (of course).

But then your sentence...: "I then draw circles in CAD of each distance".
I don't understand what "each distance" is here. We measured ONE distance before.

Or... may be, do you have a small picture, probably the best way for explanation this seemingly simple problem ?

Thanks,

Hessel

 

[John MacArthur]

Hessel -- I was afraid I didn't explain that well enough. Here's a diagram of what I'm talking about. "each distance" refers to the two center distances taken from the depthing tool.

Johnny

 

[Hessel Oosten]

Johnny,

Clear now. Thanks a lot !
Enjoy all your contributions a lot (and do learn from them).

Hessel