The First Cut….

.. is not the deepest, but it is the most nerve-wracking! After many test passes through air, I finally let the mill engrave some acrylic sheet… with relatively pleasing results!

If you can’t see what it is, it’s a skull & crossbones!

CNC Milling Machine First Steps

I bought a small Proxxon MF70 milling machine last year to help out with a few modelling jobs here & there, but also with the aim of converting it to CNC control (or rather CN control to be pedantic).

As an xmas present to myself I finally splashed out on a CNC conversion kit from www.ideegeniali.it which included the stepper motors, motor mounting hardware and motor controller electronics. I’m using an old PC I never got around to throwing away as the ‘brains’. The controller uses an old style 25-way parallel port connection so I had to get an extra PCI parallel card as most motherboards don’t provide these any more (even ones from 2005!).

I’m now starting on the very long path to undersanding how it all works, but a few days tinkering have got me as far as getting my first responses from the mill to some G-code which was really exciting!

Rather than actually milling something and making a mess all over my computer desk where it currently resides, I just inserted a pencil lead in the chuck and got it to draw instead.

 

Handy Sander

I recently spotted this battery driven pencil eraser in Hobbycraft. It’s about the size of a fat marker pen and has a simple friction chuck to hold small sticks of eraser material.

The chuck is simply pulled out, and the eraser pulled from the chuck.

I’ve been using Garryflex abrasive blocks for a while for sanding irregular surfaces – these are a rubber-like material impregnated with abrasive grit. They are relatively soft and can be cut into smaller bits easily with a hobby knife.

I cut off a 5mm slice from the end, and then cut that into 5mm sticks. These sticks can then be inserted in the eraser chuck. Although they start square, the soon wear down to a rounded point.

The tool can then easily be worked into tight corners and concave surfaces that would otherwise be hard to reach with sandpaper. Here’s an example wornking on a filled seam on the Moebius Invisible Man kit.

Note: Always wear eye protection because particles of grit can fly out in all directions as you work!