New Toy
by John
I have been looking for a CNC milling machine for over a year. My requirements were that it had to be affordable, not too big for my workshop, not too big for my 3 phase converter (max 5hp), use Mach 3, and be in reasonable condition.
What I got was good value I hope, big, 6hp, does not use Mach 3, but I think that it is in reasonable condition.
See photo below.
It is an Extron (Taiwonese) 1997 model, vertical CNC mill, which uses a Fagor controller (not Mach 3), weighs 2.8 tonnes, and is BIG. Too big really, and I hope that I never have to move it again. It required a crane to lift it onto the truck which I borrowed from my neighbour. The truck (and me now, and the mill) smell of pig shit, because that is what the truck was used for the day before. But the 550km round trip to pick it up was completed safely. Now I have to organise a crane at my shed to lift it onto a steel plate outside my shed, from where I can push it into position (on rollers).
That was the longest truck trip I have driven since getting my heavy rigid licence a few years ago, and I feel quite proud to have completed it without a problem.
I will fire the mill up next weekend. Wish me luck.
johnsmachines 
Mmmmmm CNC mill.
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That is big. But what about the tooling is will need? Is it an international socket if so what size?
john f
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One big positive is that the taper is the same as my current mill. NT40 for which I have a fair amount of tooling and adaptors. The air drawbar is not working but I hope to replace a faulty valve to get it going. Otherwise I will need a new pneumatic drawbar. I will check the electronics before committing to any further expenses however.
A good aspect of this machine is that it can be used totally manually. Ie the handwheels operate the ballscrews. An interesting and hopefully useful setup.
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I am not sure that you can get two ballscrews to work with handwheels. The problem is that if you have acme screws you cannot push the table and get it to move against the screw. If you have ballscrews you can.
You need to use the electronic handwheel as provided in Mach 3. I think. I cant find the manual.
john
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The hand wheels operate the ball screws. To use the hand wheels, the servo motors have to be switched off, and the hand wheels engaged and locked into position. The digital readout on the XY&Z axes still works though, so the servo encoder must still be switched ion, despite the motors being disconnected. It seems like an ideal entry level tool to get into CNC milling. .
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The hand wheels can be engaged to use the mill manually (but with the XYZ position showing on the electronic display), or the hand wheels can be disengaged to use the mill in CNC mode.
I gather that this was an arrangement used mainly in the early days of CNC and not often seen now.
The X and Y are definitely ball screws and I think the Z is a ball screw, but have not yet examined the Z to be sure. The Z axis has a very heavy counterweight, inside the main column. The maximum specified job load on the table is 900kg! I bit more than I will ever need.
Also there is a quill, to enable hand controlled, non CNC drilling. The quill is stiff… feels and looks like it has never been used. In fact, the whole machine appears to have had very little use. The bits of external damage (protruding bits broken, scraped paint etc) is the sort of damage which probably occurred in previous moves. The mill came from a university department.
More photos to follow soon.
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I checked the specifications. Z axis screw is also a ball screw.
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