Paul, that's an incredibly impressive piece of work. It looks like you're using quality components. A wild guess is it'll cost more than a basic 4 axis CNC Shark machine from Woodcraft. Estimated cost?
Other than making the cutter normal to the work I don't see anything I can't do on my 4 axis machine (mine is a knee mill which gives me more Z axis than most routers). Generally if possible I try not to use ball nose cutters normal anyway because of the dead zone at the center.
Looking carefully at your pictures it doesn't appear it does v-carving for inlays, pewa inserts and text. That can also be useful for chip carving among other things. Picture shows a v-carve inlay of ebony into an unknow very hard wool Notice the sharp points.
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Thanks, Doug! The silver one you see in most of the pictures has high quality components (Parker linear axes with ball screws, linear rails). I got most of those parts from next to a dumpster, so the cost to me was...negligible. That was the first iteration, but as you note, using those components would cost quite a lot. As primarily an engraving machine (minimal cutting forces) that is bolting onto the lathe, it doesn't actually need quite the amount of rigidity I get from the nice components, so I settled on using OpenBuilds based C-beam extrusions for the linear axes. Right now, these use V-slot wheels on the gantry, but the next iteration will use linear guide rails. Those versions you'll see in a few shots with black aluminum extrusions. There are a number of trade-offs but some big advantages to that system as well (cost being the large one). The OpenBuilds version BOM is around $800.
Putting the cutter normal to the work is the magic sauce, though. If the cutter can reach it, I can cut the exact same pocket anywhere on a bowl (bottom, side, rim, even the inside) using the exact same starting gcode. I just have to account for the diameter at the cut site and the tool rotation, and my custom gcode sender will do all the coordinate transformations on the fly. Effectively, you end up cutting into a plane normal to the cut site. I have worked it out so you can even cut the pockets with flat bottoms (adds extra Z-depth at the cut origin) to fit inlays that are cut out on a 3-axis CNC/laser. Unless you have a very unique 4-axis mill I am not aware of, having the tool orthogonal to the rotary axis won't allow you to make those cuts at any arbitrary position on the work piece.
The machine is fully capable of V-carving. You can use any 3-axis gcode and the software I've worked on will convert Y movements to A rotations (based on diameter) and will alter X and Z coordinates based on tool rotation (B axis angle). I've found V-carving in curved surfaces much trickier than doing it on flat pieces, because since you are working in a plane, the work piece falls away where you have most of the v-carving (edges). The only real solution is to make deeper cuts, which isn't always an option. EDIT: Or use specialized software (GrblGru) which can do this.
It doesn't end there though. Obviously, lots of laser possibilities, and there are some photos/videos of thread cutting, which is the latest thing I've added. You just put in the parameters and it writes the gcode for you:
That's probably more info than most others care about! I'd love to chat more about it in direct messages, or if anyone is interested, I have a Discord server where I am providing support (right now it is just for the couple of people that are Beta testing machines).
Check out the LatheEngraver Support community on Discord - hang out with 5 other members and enjoy free voice and text chat.
discord.gg
