The plans for the 4×8 machine require 4 quarter-sheets of ply, so I went to McLendon’s to pick up some 3/4″ Birch. Their stuff is really pretty compared to Home Depot. $19/sheet, though.
I briefly considered getting 4’x4′ sheets and then ripping them with the new tablesaw, but I chickened out; it’s only $6 more to buy 4 2×4 sheets than 2 4×4 sheets, and who needs that stress?
The tablesaw will get a good workout building the table for the 4×8 machine — plans call for a torsion box to keep the surface dead flat and properly supported. Not to mention a stand (made of 2x4s) to support it all.
I spent the rest of the day and well into the evening pushing the parts around in Cambam to get them to fit into the 18″x36″ cuttable area of the CNC machine. This presented several challenges.
First, the graphics included plans for the v4.0 Blackfoot, but also a sheet of revised parts to bring the machine to v4.1.
Second, the pieces for the 4′ wide Y table (actually 52″ ID, and even wider OD) take up a lot of room on the plans, so they have to be carefully placed in a way that can cover all of the parts.
Third, there are 2 pieces that simply can’t be cut on a 36″ table, namely the Y axis top and bottom, which are ~3″ wide by 46″ long. I’m going to have to fab those on the tablesaw, or else I’m going to have to find a different way to create these.
Finally, I need to make sure that all of the parts have sufficient spacing between them so that the toolpath creator can do its job. I also have to figure out all the parts that have pockets and make sure that I’ve covered them all properly.
Once I started working through the various constraints, I was able to get everything pushed and shoved into place, and I now have a set of drawings to create a v4.1 machine in 4 quarter sheets of ply, with a cuttable area of 18″x36″ on all sheets (ok, one sheet needs 18″x38″, but that’s not a big deal)!
I need to do some final sanity checking to ensure that all the parts have proper spacing. Then I’m ready to start cutting.
Once I finish the 4 sheets, I’ll have a bunch of scrap left over, as each sheet will have about 3″ on each side left over, and about 12″ at the end. From that set of scrap, I need to cut the following parts (moving the parts around on the diagrams as appropriate):
– the aforementioned Y axis top and bottom (2 parts)
– the router shoe (2 parts)
– the lower vacuum mount (2 parts)
– router mount rings (2 parts)
The router mount rings I’ll have to design myself, as I’m using a different type of router than the Blackfoot plans ship with. I already have a CAD that I designed earlier, and I should be able to modify that pretty easily to create the required part.
I have some work to do to turn these drawings into machine operations, and I’ll have to do some additional cutting once it’s all done. And I will need to buy hardware to put the whole thing together. But for some strange reason, I feel like the hard part is done.
Onward.