I wish I’d had a project to cut before the Blackfoot, to get myself back into the swing of things. I had a pretty rough time with the first two boards of this project, but once I started really tuning up the rig, board number 3 went off without a hitch.
Now that it’s raining, I decided that I had to move the CNC inside to keep it from getting rained on. I did not want to have the same dust problem as before, so I knew that I needed some way to contain the rig. Kristi offered the family tent, as she is apparently in the market for a new one, so I set it up inside the shop and put the CNC table inside.
Let me take this moment to say that it’s ludicrous that I can set up an 8-person, two room tent (approximately 7’x12′) inside the shop. Back to the show.
I got the vacuum set up on a separate circuit so that I could gather dust while it was being made.
Knowing that I was going to be in an enclosed area, I grabbed a dust mask (!), safety glasses, and earmuffs, and got ready to cut.
I also set up a MOP to throw in a 0.5″ deep drill hole at 0,0, as suggested by a previous commenter. This, above all else, was probably the major reason that today went so smoothly. I re-homed the axes after each MOP (outlines, small drills, large drills, pockets, and cut outs), and the axes were off noticeably each time; just a couple hundredths of an inch, but I am betting it would have added up by the end of the day. Re-homing saved my sanity; thanks again for the tip!
I have also been enjoying the “outline” MOP that I’ve been throwing in. Being able to see where the part boundaries are really helps me to visualize what’s going on with the rest of the cut.
I decided to watch the whole cut, like a hawk. I also vacuumed up a lot of the dust right away, and was pulling parts off the machine as they finished. Watching the router to see where the cut would finish, then holding down the part with my hand once the router got to a safe place… it was something that required concentration.
Finally, I decided to re-grease the X and Y axes after each MOP. It’s probably overkill, but the axes were running really smoothly, and I began to look at my screws as “machine parts” instead of “fasteners” for the first time. I understand why having an oilcan around moving-parts machinery is a good idea. Thanks, Tin Man.
These careful considerations made for a pretty easy cut.
I have just one gripe about the way the cut went today. I have been having the same old problem where my < 3/4" workpiece (it's nominally 18mm, .70") is not getting cut all the way through with my -0.75 Z depth. This is probably because the Z axis gets out of synch sometimes. I had to re-home it twice during the day, and I noticed that a lot of pieces had holes that were not punched all the way through. Oh, bother. I'll do them on the drill press, or even with a hand drill, since they are drilled almost all the way through. Setting the Z depth to -0.85 was not the right answer. That messed me up on board #1. The edges on the parts are really nice today; there is a noticeable difference in the tearout between the earlier cuts and this one. I think I might be sold on the yellowish TiN coating. Or maybe it's the 4-bladed endmill. I dunno. I like it. I threw in some screws to hold down small pieces of scrap in between the parts. I think it helped. One more board to go. The final one will test my X axis travel, as the parts go out to 38" instead of 36". I checked carefully, and the board is set up with a hair over 38" of cuttable length. It extends past the X table by a couple inches. It's all fully supported by spoilboard, of course, and the axis could physically travel at least another inch. But it's new territory, certainly. All the parts need sanding. I need to head out to the lumber yard and get 4 sheets of MDF and a bunch of 2x4s and 1x4s to make the torsion box, too. And I need my nuts and bolts to show up on Monday. But I am getting awful close to having all the parts for a new CNC machine. Awful close, indeed.