11/18/2019 at 07:15 •
An elementary but not obvious fact of milling: a machine that's weaker cannot just simply go slower. Every time a cutting edge of a spinning mill bit comes around, it has to be far enough advanced into new material to actually cut and carve off a chunk of material. Otherwise it's just rubbing, and maybe ablating some material, but mostly making heat rather than progress. Trying to remove material that way quickly turns into too much hotness for either the cutter or the material. Like, stirring a little puddle of melted acrylic. Or if the spindle motor can't even make enough power to heat stuff, then nothing happens.
So there is no "slow" in milling. The machine either can push the cutter through the material fast enough to push each edge into new material, or it can't.
Cognoscenti call this "making chips".
My ignorance of this was a critical enabling capability for starting this project. Because clearly there's no way a CDROM sled can shove a mill bit through anything harder than floral foam.
11/18/2019 at 06:57 •
Part of the voluntary difficulty of this project is the game of scavenging. Buying stuff is a kind of defeat. Of course you can buy a whatever for whatever. But justification for liberty in buying parts very quickly converts to warrant for simply buying a CNC mill that will be better for less than the ultimate cost of completing an inferior project paid for in small increments of direct cost + time not actually using the better machine.
On the other hand, working through building a whatever from temptingly cheap/found parts is a great way to learn what is the value of a more costly well-finished product.
Making stuff on the cheap is a hobby, not a profitable enterprise. If not fun, then likely not actually economically justifiable. Assuming first world circumstances where everyone specializes in some way to generate income more efficiently than than they can avoid expense by not paying others to do what they do more efficiently.