This is way cool. The accuracy and repeatability is top notch.
I cut the front plate of my machine into three pieces and threw the middle away. I then re-attached the bearing holders with new standoffs to allow me a little more reach over the end before the gantry wall hit them. I now have almost 2.5 inches of reach and 36 inches to the floor. This will be enough for several setups including mortise and tenons, dovetails, and finger joints. The center section has 4 T-nuts for bolt-ons.
I then built a jig that bolts to the center section. It is basically a clamp and two towers. These two replaceable towers are milled from above to the same height. The height doesn't matter as long as they are the same height. I then place a straight edge across them, line up the work piece to be level with the straight edge, and then tighten the clamp with the two black levers. The towers also allow easy clamping of a temporary backing board.
The next problem is finding 0,0,0. It is absolutely critical to get this lined up correctly (twice). I am using an aluminum touch plate that is wired to my emergency stop input and a separate alligator clip with a wire to ground the router bit. I am using spacers to hold the hold the touch plate 1/2 of the width of the router bit away from 0,0. I jog the bit over to the touch plate; it automatically stops, and I reset each of the DROs, one axis at a time. I am finding it very accurate. My 0,0 is the upper right corner of the work piece.
I am using the bottom of the dovetail as Z0, so I don't have to create new G-code for different thicknesses, and just use the touch plate to set the depth. The three different thicknesses of boards in the pictures were all cut with only one set of G-code. To set this depth, I use a scrap of the board that will mate with the one being routed as the touch plate spacer. This is referenced under the straight edge that is laid across the towers.
I am using Vcarve to do the CAD and CAM. I had a bit of a go, getting it to do what I wanted, but it did it.
Steve |