So where is the vid??
i was poking at the nm070 today. i have some drange chatter issues that im trying to resolve. they happen only with deep cuts on a .5" 4 flute bit. my guesses are a combination of minute play in the gibs, ball screw mounts, spindle bearings, runout, and the result is a resonance that builds up every few seconds and heaves the spindle over as much as .05". it happens no matter how slow or light the spindle load is, but only on deeper cuts (.25" or more). anyhow, the machine is getting modified in a number of ways to reduce flex, so in the meantime i can just not cut like that.
i can actually run 100ipm with this cutter full width at .02" depths, so theres no real loss of efficiency in metal removal.
anyhow. i was messing about in jog mode, and the aluminium block was getting close to vise hight. i clipped the top of the vise. this is a 2" toolmakers vise, made of hrc50ish tool steel. rather humourously, with all the chatter issues, the thing just ran through the vise!
so i did a test.
10ipm, .020" depth of cut, full width, 5000rpm. i was using a 4 flute maritool variable flute mill with .03" radiused corners and tialn coating. actually not meant for aluminium at all, its meant for cutting tool steel! and man it does it well, even on this tiny machine. sparks went flying, and the surface finish is like glass! the key here, as some of you may know, is puting the rpm high enough with a feed agressive enough that the chips come off glowing so the tool and workpiece dont heat up. no coolant is used. in this case i had 650sfpm and that was just the right amount. im pretty sure the raduis corners on the bit help out alot, as well as the variable flute geometry.
ill do a program tomorrow to resurface the vice and film it. its a shame i cant do this with smaller bits (no rpms) cause id be off making dies!
there you have it.. you CAN actually hard mill on these little bench top machines.
no video, camera was misbehaving. heres a photo though of the finished surface. machine is getting torn down to get the dovetails worked on.
so i lapped the x and z ways, made a dramatic improvement. no more slop in the z. gonna finish the Y and put the machine back together today. i need to get some materials, and then ill video the machine doing something in hardened steel (among other things).
anyone on the toronto are know where i can get pre hardened O-1 or M-2 steel?