A few years ago, I brainstormed doing a big-bore (3 inch dia") CNC lathe
from scratch.
Regarding the photo (hope it uploads!), it is fashioned out of only two
pieces of sheet steel (cardboard here). One piece is the vast majority
of it, (plasma, waterjet or laser cut) and folded, then welded along some
of the seams. One thicker piece (say 3/8") forms the insert where you
see the chuck (tin pot) hanging off it. This piece gives rigidity to the
whole structure.
Note the X, Z and feedrate override knobs (margarine containers!) and
big 4" voltage & amperage analog guages.
The bedway would be a 12"*12"*48" cast iron block, cut lengthwise
into four 12" wide * 3" high * 48"L beds (to make four lathes). They
would then be ground.
On the inside of the cabinet, another 12"*12"*18" solid block of cast
iron would be machined to fit a few big taper roller bearings and the
spindle, then bolted to the main bed.
The spindle motor (3 - 5 HP) would cog-belt drive the spindle through
either a low speed pulley set, or a high speed pulley combo (manually
changable).
In the backside, there is a big 4" depth space for electronics & coolant
pumps etc.
The rest, (carriage, cross-slide, power chuck) I haven't figured out yet.
Any interest out there in this type of project? Probably would have to
sell for at least $10K, as making it would be a lot of work. On the other
hand, thats cheap for a 3-4" bore cnc lathe.
cheers
Doug Fortune |