OK, I cheated, not so much machining a ratchet as working out how to create a ratchet in Carbide Create.
A quick mention for Carbide Create as it is free for the basic version and for what I do this is enough.
This software is easy to use and very flexible. Previously I used this to create the code for the kant twist clamp.
I used the centre of the material as my origin. Then I drew circles on this centre. The middle circle of the three outer circles is just there as a reference to align the first triangle.
Look at the triangle east of the centre and you can see the base is angled to give just a slight capture for the pawl.
The triangle was then 8 times around the circle using the circular repeat function in carbide.
The toolpaths were set to machine the inside of the 3rd circle in from the outer edge. Then the inside of the 9 triangles. Then the inside of the 3 off 2.5mm holes and finally the outside of the outer circle, 40mm in diameter.
OK, I did finally machine a 6mm hole in the centre as I realised I could use the waste part in the centre as a ratchet at some point in the future.
This is machined on my heavily modified Genmitsu 3018-pro. The brass was 1.6mm thick. Here are the basic specifications of the tool and cutting settings:
- 1mm 3 flute MillingCuttersStore bit
- 5250rpm
- 60mm/minute feed rate
- 40mm/minute plunge rate
- 0.1mm cutting depth per pass
The settings mean this is not a fast cut and took just under 100 minutes. However, this is a part that would take me ages to machine by hand.
The brass ratchet cleaned and polished.
Here is the ratchet sitting in what will be a winding drum, but that’s another story.