Patrick's machine is purported to be the first modular design for a CNC machine- this kit can be scaled from a 2x4 design to a 4x8. He accomplishes this by building the main structures with an I-beam design. If you want to make the machine longer, you can add additional I-beams to make it 8' long. Likewise with the width- adding another I-beam to the width widens the workspace to 4'. After adding I beams, you replace the leadscrew and the angle iron tracks with a longer ones and reassemble. This lends itself to some flexibility- you can configure your machine as a 2x2, 2x4, 2x6, 2x8, 4x4, 4x6 and 4x8. (and possibly even longer if you can find the acme screws for it!)
Space is a serious commodity in my shop, so I stuck with the 2x4' machine.
In my kit, all the I-beams came pre-assembled, which was handy. All you need to do is line up two I beams, grab 2 connector plates and 8 nuts and bolts. After bolting them together, attach the legs with bolts and dowel nuts.
Mine didn't go together quite so smoothly. None of the connector plate bolt holes were countersunk enough for nuts to get a bite on bolts, and the X parts are not symmetrical on the horizontal axis. This means it is very easy to mate one I beam "up" to one oriented "down," resulting in a joint that has a nearly .125" stairstep between them, which would prevent or at least mess up movement of the gantry back and forth. I evened them up and drilled out the countersinks and got them all bolted together.
At this point I also made the executive decision to stop using nuts on the angle-headed bolts for the aluminum angle. The bolts are stressed in at a slight angle and bite hard into the MDF- they aren't going anywhere.
This time, I also didn't crank the bolts down hard onto the alum angle- I'll align it precisely with a caliper later when I fine-tune it all up. |