I`ve spent a little while finishing this count wheel but managed it last night! The count wheel has these ratchet like teeth so that as the pendulum swings, the gathering pawl/wire slides up one of the slopes and drops behind a notch pulling the count wheel around one place.
I started with two rough cut pieces of 18g CZ120:
Made an arbor and chucked them both up:
Turned them down to 1.5″ diameter:
I then made my profiling tool to cut the teeth, a 60 deg cutting tool but I needed a flat parallel to the mill bed when mounted:
I then unscrewed the chuck and mounted it on my rotary table on the mill. It managed to get out of true when I did this in my previous efforts so I set up a DTI just to check it was running OK – which it was this time! I must have knocked it last time, but my arbor was also longer in my other efforts which may not have held as well. Also, it sounds stupid, but I think there was some vibration last time and the chuck wasn`t tight on the rotary table that is why it didn`t cut properly.
I then centred the wheel – made sure by making a whitness mark, moving to the other side and checking it was at the same height – you can just make this out on the photo
I started cutting the teeth!
Wheel teeth cutting complete and worked just fine!! :ddb:
I was then in two minds – remember I cut two wheels at once since it is thin 18g brass, the two together provided support for one another. I didn`t want to cross them out together as I risked spoiling them both if I failed. So I opted to remove one (as shown above) and remount the other on the chuck arbor and mount it under the rotary table. My Dad then kindly helped me with some nice math calculations so I could calculate how many degrees I needed to rotate the rotab with the cutter down and then lift the cutter for so many degrees and then back down etc to cross the wheel out..
Then it was time to file it all square. I appreciate I could have got much more accuracy using the rotary table for all the crossing out but I decided to saw the little pieces out and file to size as described in the plans. This is the setup I`ve seen people use – a long wooden board, a groove cut and you sit on the board with the work nicely on platform infront of you …worked very well
And after 20 minutes of rough filing I`ve got it coming to shape.
OK OK – it needs a lot more filing to make it look neat and quite a bit more work on burnishing the teeth but I`m nearly there….