This Is a Massive CNC Mill — Not a Router
Most of the machines you see with huge beds as big as your mattress are CNC routers. But that isn’t the case with Jornt’s massive CNC mill.
What is the difference between a CNC mill and a CNC router? The lines get blurry and every definition has exceptions, but generally speaking, CNC routers are low-precision machines for cutting wood and CNC mills are high-precision machines for cutting metal (let’s just ignore plastic). As such, most of the machines you see with huge beds as big as your mattress are CNC routers. But that isn’t the case with Jornt’s massive CNC mill.
This is a completely custom, DIY CNC mill with a truly gargantuan bed measuring 4×8 feet. That size is usually a sure sign that a machine is a CNC router, as those are the dimensions for a standard sheet of plywood. And this machine certainly can cut plywood. But it is far more robust and rigid than a CNC router. It has the ability to cut steel, so I think it definitely qualifies as a CNC mill — just a ridiculously oversized one.
Rigidity and vibration dampening are critical for a CNC mill, which is why they tend to be extremely heavy and made of cast iron. But casting iron for a single machine is not at all practical, so Jornt built the frame from welded-steel tube filled with concrete. It has a truss gantry riding on actual linear rails with 32mm ball screws all around. It even has a custom enclosure, made of steel sheet, complete with clamshell lid that lifts to provide unrestricted access.
On the electronics side, Jornt used a Masso G3 system. While Masso is affordable by industrial standards, their systems are very well-regarded for hobbyist builds. There is a VFD for driving the spindle motor, servos for each axis, and a rack of toolholders for the automatic tool-changing function.
Does it all work? You bet it does! It is a little funny to see a 6” vise mounted in one corner taking up only a tiny portion of the bed, but Jornt can use that for jobs of a typical scale. Then he has the entire bed to work with if he wants to mill anything huge from steel.
Of course, he can also use this machine as the most overbuilt CNC router in existence when he wants to cut plywood.