Thank you for the support.

I can claim no credit for the centring micrometer as this is something mentioned in Malcom Wild’s book, “Wheel & Pinion Cutting in Horology”.  Although it shows a couple of photos of the tool in use and a description, it goes on to comment that such a tool “...can be readily purchased“.  Alas, the book seems rather light on the detail of exactly where such a tool can be readily purchased!  No matter, a bit of time with crayons sketched out something possible.  Three lumps of steel were silver soldered together and then machined all over.

With all the wheels sporting teeth I could move on to the pinions, feeling slightly cautious following numerous comments found online about how much extra care is needed compared to machining brass wheels.

I don’t have flood coolant, but numerous comments suggested this would be important for the pinion cutting.  I invested in a cheap windscreen washy pump kit from Amazon (or was it EBay?) which was hooked up to a variable bench power supply so I could adjust the voltage/flow.

When it came to coolant choice itself I went with white spirit – might not be the best option, but it would certainly be better than nothing at all, was cheap, and readily available.

A small plastic tub was located under the cutting operation to catch the overspill.  When that filled up I just paused machining, tipped the used coolant through a kitchen-paper filter in the top of a funnel to remove the metal shavings as it went back into the pump reservoir and then started again.

Whilst the brass wheel teeth were cut through at full depth, the pinions were tickled into being with multiple rotations at lighter depths, with the cutter running rather slower and my manual feed rate taking it steady as well.

I was unsure about providing tailstock support, but decided to wing it and try without…

The book talks about leaving the pinions unhardened, but I decided to pack them with boric acid to prevent scale and then hardened and tempered them before finally polishing to a mirror finish.

With the gear cutting all complete, the next focus was crossing out the wheels to reveal the spokes.
Some effort with 2D CAD worked out the diameter and radius where I needed to locate pegs (heavily disguised as drill bits) on a jig against which I could rest a straight edge to produce the spoke lines for all the various diameters of wheels:

I didn’t like my chances of accurately filing to the line, especially as keeping the whole thing balanced seems an important idea, so I went to the rotary table:

I’ll admit the process was not quick and my heart was in my mouth much of the time – especially with smaller diameter wheels which used decidedly smaller end mills.  Despite this I emerged from the process with the same number of cutters I started with.

Towards the end of the build I came to make the weight pulley, by which point I didn’t have the enthusiasm to set up with the rotary table again, so for that I filed out the spokes and rim by hand despite the material being somewhat thicker. The end result seems just as good and wasn’t really any longer time wise.  In either case, all the final finishing with fine polishing papers was careful manual work anyway.

So here we are with all the components made to date (including a bronze screwdriver designed to fit the large blued screws so I don’t risk damaging them as they get handled)

Ian.