Wizard for clockmakers.

[fullacott]

Ron,

I do a bit of work with clocks and the idea of a crossing-out wizard is attractive. I am not sure, however, that scaling the parameters in proportion to the outside diameter alone would meet everybody's needs. The thickness of the rim (outer annulus, or whatever you wish to call it) is often related to the size of the teeth as well as the OD of the wheel. The escape wheel in your picture has quite large teeth in order to do its job while a meshing gear with a high tooth count might be expected to have a narrower rim, not least because the loading would probably be less.

In a similar way, the size of the boss (circle defining the innermost points of the cutouts) would not necessarily increase in diameter in direct proportion to the outside diameter.

This is not intended as a discouraging response, just a contribution to the debate from someone who has so far used CAD only and is intrigued by the thought of a wizard. How hard would it be to design a wizard which allowed the input of the inside diameter of the rim, the outside diameter of the boss, the number of spokes and and the radius of the corner of the cutout next to the boss? Together, of course, with inputs to cover thickness of material, depth of cut etc.

The appearance of clock wheels is quite important and elegance as well as functionality have traditionally been factors influencing quartering.

Hope this is helpful. Peter

[dugbell]

Hello !
New to the forum but a keen clock repairer (amateur) - I am at present building a small cnc mill to do crossing out, but it will be a while before it is completed ! - am very interested in this project , unfortunately I do not have the gcode skills at this time to contribute , I find cutting brass can be a problem with small milling/slot cutters and as some corner shapes in older clocks are sharp - not a radius , filing to a finish is often required.
thanks
Doug

[biffo]

 Hi
I make quite a few clock gears and use my small cnc mill which I converted using a sieg mill. I draw the gears from the original and post it into lazycam as a dxf file then send it to mach3 it works fine and the crossing out is perfect but as you say you will have to file the corners if you want a sharp edge.

[RICH]

All you clockmakers should have a look at this site. Art has created a program which creates all types of gears.
http://www.gearotic.com/

RICH