If you have been following my other robotics threads, you'd know that I intend to offer a kit for retrofitting the lilliputian-sized Sieg X2 micro mill (sold as the Grizzly G8689, Harbor Freight 44991 and several other brands) to a full 3-axis automated mill.

While waiting for time on the big mill, I had a chance to set up this puppy and start using it manually to produce RoGR parts. Using the mill manually is giving me a good feel for its capacity and how I should go about automating the thing. First impressions are:

I love it! Too cute!
Room for easy improvements all over.
Simple to automate.
Great size, great price. Can be used in a dorm-room.
Capable of making high tolerance parts in metal.
Variable speed motor (same as mini-lathe) is sized well and convenient to use.
My arm hurts from turning dials!

I mounted it to a sturdy, level work surface, and even threw-in an extra piece of ply, but this mounting is not satisfactory. The X2 seriously needs mass at the bottom, so bolting to something like a 2" thick precision-concrete base, or perhaps 4" of MDF glue-lam is in the cards (ugh). A nice slab of steel would do...yea, 1.25" steel plate sounds perfect. For the 1 sq' footprint, that would add about 50lbs, but yikes it would cost ~$150 delivered! Concrete!!!!! Almost dirt cheap.

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The X and Y ways use the same nut, this nifty bronze piece. There's no lash compensation ~per se, though black magic opportunities exist! I don't see the point in paying $500 for a machine just to strip it of some of the more expensive items, as some retrofitters do. The screws are high precision, tight lead and very capable. The bronze nut is a quality piece that is easily converted to include lash compensation:

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One of the most desirable qualities of this little machine is the full complement of dovetail ways on each axis. This gives the user maximum control for square-rigidity. Remember though, on it's supplied base, it is weak. Here's the X axis; note the fine pitch on the screw:

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Random ballscrew-sample image just to confuse everyone:

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Hey, that NEMA 34 motor looks like it belongs there...

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So, since Robin was hogging the big mill ahem; as usual, I had to use my wits to avoid some bad arm cramping from {edit} facing RoGR nuts with a little old 1/2" endmill.



More of that:



I had to take some 2" deep plunges with the 1/2" endmill into the UHMWPE RoGR nuts I was machining. I think UHMWPE is downright nasty to machine; since it doesn't wear much, how do you easily cut it? You'll note that it loves to wrap about the mill in strings, due to the very very very long polymer molecule that makes this stuff. The X2 handled the material far better than any drill press:

I was originally looking at converting one of these to CNC - it was the search for reference material that led me to your site!

Having seen the thought and effort that you put into your other projects, I'm sure you'll come up with a great solution. You've given me quite a dilemma though;

I was all set to order the micRo, but the X2 machine has just enough working area to do the engraving I need, plus the extra grunt to machine a set of joystick gimbals from aluminium.

Something along these lines (but not quite as complex):



Got a rough idea yet of the sort of cost we'd be looking at?

~S~

Hi Valisk, Nice logo!

I'm desirous of keeping the full kit cost <$500 so the mill + kit doesn't exceed $1000. I will also offer a cheaper kit with just electrics and couplers, for those who have a micRo or RoGR and can fabricate the billet themselves.

Critical to the price is how the Z gets automated; whether the rack and pinion gets replaced.

Thanks BC!

Can't wait to see how this thread progresses, although it looks like you've got your hands full at the moment with the micRo and RoGR projects!

~S~

Always full, two little ones too. Life is hard, but good!