I don't see enough posted regarding the pro's of these little machines , so I'm posting a bit of a review which is something I rarely do , and it can be taken for whatever you see worth . If I based my purchase on a lot of what I've read at the time then I may not have bought these , but I knew what I needed and I based my purchase on those needs . Like many other guys , over the years I've worked with so many different brands of industrial cnc's , and my opinion of hobby grade machines is reasonably based on my experience from jobbing shops to production shops

I've own 3 440's for nearly 3 yrs now which I use as production machines . Thinking back I wouldn't have done things differently and I just got a quote for another one . What has really got me to thinking is the fact that they have been so reliable and consistent .

The other day I had the angular contact bearings go in one of the z stepper motors which was in a sense a pita but no biggie . Especially since these mills have seen an exceptional amount of use .
I don't do any hogging but I have put countless hours on these mills almost every day since setting them up and the z is almost always in constant motion . I've seen it questioned in the past in regards to the motors having the contact bearings built into them and I wondered their durability as well . I'm impressed considering this is the first one I've blown after all that machining without a single adjustment , and a $195 expense after thousands of hours and parts is nothing . I wouldn't want that setup on a big mill but it's proven to be solid on these small mills

The only other parts I had to change on another mill was the spindle driver , and all 3 needed new oilers . 2 x axis steppers needed wires soldered back together after breaks because the conduit is a bit of a turd which eventually breaks and cuts through a wire . The conduit is plastic wrapped metal which doesn't have a lot of give to it , it should be full plastic in my opinion . That and the tight way covers pretty much cover it for complaints . More thought into limit switch placement would help to though .

I've seen a number of complaints about the mx3660 drivers blowing and I haven't had that happen . From what I've gathered is they blow when e stopped , so I never press that button , even when powering down . I honestly don't know if that is the actual cause of the problem , but why risk it , the esc key is just as quick to hit if things go south

A ballscrew swap pushes the x axis to a little over 11" and the y axis can be pushed to 6.5" which is a bit of gain . I see a lot of bigger is better , and to each his own . If a bigger work envelope is needed for the parts then bigger is better , but most home hobby shops aren't making big parts and bigger isn't going to make a better part unless a guy goes to the next step and buys a hass . I have a torus in the corner that takes up the working space of the other 3 , does the same parts and has had far more repairs done to it than the others combined .

The draw on my power is nothing considering the fact that all 3 mills are on the same breaker , which means a guy can stuff a garage with these things . I rarely power them down so that I can wake from my morning coffee and load stock and go . They do not lose position .

Anyhow , these mills have been nearly bullet proof with all things considered . There will always be little hiccups here or there but nothing different than anything I've experienced while working with industrial cnc's or whatnot . For anyone considering one of these mills with the understanding of it's limitations then I doubt you'd be disappointed