In 2004 I bought a milling machine
from Chester UK. Up until then I'd been using a Sherline
CNC milling machine. The Sherline was a fantastically good little machine, but had one flaw (or perhaps it was just me). The Sherline
is very good for small, but having caught the machining bug, I wanted bigger, more powerful! Unlike the Sherline, the Eagle-25
milling machine I bought was not CNC-ready. A CNC-Ready machine has all of the mountings needed for converting to CNC (computer
numeric control) all you need to do is add motors and go, but on a manual milling machine you're stuck with 3 handles: X, Y and Z.
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| This meant I had to do quite a bit of work to convert it to run CNC! This included building enclosures, making electronic safety
circuits, adding motors, machining pulleys and brackets and hooking it all up together.
About a year later it was all done
but not incredibly accurate: the mill was still using it's original leadscrews, which are basically just a screw thread that converts
the rotation of the motor into the linear movement of the mill table. Since these are nothing much more than a fancy nut and bolt
they tend to be as accurate! The problem is that there is a massive contact area (the threads interfering with each other) and the
very necessary oil/grease that keeps it moving causes a type of hydrostatic pressure. The result: it's okay for big chunky bits
where you don't really care about accuracy, but as soon as you want to get detailed it's sloppy and all over the place.
Finally in late 2005 I moved house, to a much newer, nicer, place. Unlike the industrial wasteland that my prior flat was, my
new home is rather comfy and tidy. As I live in London, I don't have a massive place, so my milling machine sits in my lounge! At
my old, very-studenty abode, this was not a problem, but in my new home, this sets me a challenge: Build the mill into a very nice
stealth cabinet, so I can go from drinking tea with the landlady to milling titanium in 25 seconds! (and she won't know!)
It also means I can finally install ballscrews, improve the accuracy and fix all the "bugs" of the old system. |
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