Saturday, 27 September 2014

CNCing about Part 3


I manged to spend a little more time on the CNC mill today, mainly to experiment with a few things.

Thanks to Paul and Alan who replied with regards to my previous post offering advice so I had another go...
The two gears on the left are a result of mainly changing the cutting depth of the cutter from 0.75mm to 0.3mm and reducing the feedrate slightly too. The gear on the right is the result of adding a 0.1mm backlash offset to the machine through the software and the result was strange looking gear indeed. The results are lots better than the previous attempt but I feel there is still some improvements that can be made. Contrary to my previous post I now don't think the backlash of the mill is a big problem as I first thought.

When I was watching the cutter profiling the gear I noticed that for the first few passes the cutter was slightly deflecting but as the program carried on and the cutter traversed deeper into the material the deflection reduced.

The length of the cutting bit is around 6-7mm so I might try to pick up a 0.4mm cutter which is a bit shorter and this I think will make it better.

The thing is though, I think I now have a pair of useable gears so I might try them out in an engine...


P.S. Boring post I know but things will liven up soon...!


  1. Getting there! A shorter cutter would I'm sure improve things. I shall look forward to seeing what you do with these.

  2. Im looking forward to seeing what I do with these too!
    I have been browsing the web since this post looking for a 0.3mm carbide cutter with about a 2mm flute length, there are some at 1.5mm but thats right on the limit of the depth of cut I need. Who knows, these gears might be ok anyway, I need to experiment more....

  3. Hi no not boring at all I admire people that can these things it's great stuff keep us posted

  4. Thanks John.

    Anyone can learn t do these things...