Using the CNCDepot spindle, Z-20 gantry rework

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey Carl and Lynn,

did you already have a look at this and this and this. It covers not only the best milling motor solution for hobbyists and semiprofessionals, but also what is the main difference between Onefinity Z sliders and the Z sliders of other CNC machines: The fact that the Onefinity Z slider is not able to protrude beyond the lower end of the Z assembly. Most CNC machines usually do, as you maybe observed (except one well-known hobbyist machine that also uses the hand trim router).

This is because the machine was designed to use a hand trim router (like another, very known hobbyist machine does) as milling motor, and those hand routers like the Makita RT070x have a long cylindrical mounting surface, which allows not only to accomodate your hand to hold it, but also to attach some accessories like bases that are clamped to it and can be slid up and down, and when mounting such a hand router like the Makita into the Onefinity router mount, you can slide it much downwards, so that it is not the Z slider that protrudes beyond downwards beyond the end of the Z assembly, but just the router or the spindle, and you even have to slide it that much into the mount because (at least on Original Series) if you don’t, the router’s back will bump the stepper cage when trying to reach topmost Z position. But the main reason why you have to slide and clamp it that much downward into the mount, is that otherwise you would not reach the workpiece in case it has a low height, which is because the Z slider is not able to protrude the lower end of Z assembly.

@Machinist

In mill terms, the Z axis is your limiting factor. The Onefinity makes an awesome CNC router, but the harsh reality is that it simply doesn’t have the Z axis backbone to make a decent mill.
It might be ok for aluminum, but I wouldn’t attempt steel on it, unless it was a one-time thing. You’re looking at 5" from the tip of the cutter to actual support. On a mill, this distance is much shorter and much beefier. The end mill will most likely chatter with this relatively little amount of support. That equals bad finish & short end mill life. You could definitely limp by a steel mill job on it, but not a good idea to repetitively use it to mill steel.

And after there was a strong demand by the users to be able to use 80 mm spindles, Onefinity simply offered a mount that looks the same, but with 80 mm inner diameter, but did not change anything on its design, which means the capability to reach the workpiece despite the fact that the Z slider is not able to protrude beyond the lower end of the Z assembly is achieved only by sliding the router or spindle much downwards into the mount, thereby increasing leverage force and thus possible chatter. Also one big difference is that usually Z sliders on other CNC machines have two linear bearings per rail, but the Onefinity only one:

@Aiph5u

So what you have here, is a Z slider that was made for a hand trim router and that was just offered with a slightly larger inner diameter. The design wasn’t even changed for the new Elite Series, just the chrome-plated steel hollow shafts were made bigger with 20 instead of 16 mm and the Z travel increased from 133 to 163 mm.

So when we bought our Onefinity, it was already clear we would mount another Z assembly to hold our spindle.