I'm just so tired of trying to find a way to get a relatively accurate solution worked out. I know it mostly comes down to getting a machine with good repeatability and then dialing it in with dial indicators, test geometries and so on. I am willing to do that. But I am always so frustrated in so many departments on how what I need is not on the trodden path, that I always seem to have to be a pioneer, when this is pretty basic stuff. I mean not entirely, there is linuxcnc, which is excellent work, and it has very basic capacity for software compensation for squareness error, apparently, although I have yet to determine if it is working/completed.

What I would like is to buy a pre calibrated machine at a reasonably price point. They sell highly accurate machines for making PCBs, but they have z travels that are too small, and they are ridiculously expensive. Like $15,000 for a 3040 sized machine, if you want accuracy of about 10 microns.

The thing that bothers me is also the gap between the absolute requirements of mechanical engineering and what the machines can deliver. I mean, if you have a post that needs to fit in a hole, and they are both off by 50 microns, that's just not going to do at all, is it? It's likely not going to fit to the bare minimum. So many other examples of basic features and aspects of machines and systems that just need far higher tolerances than that. And you can get that from expensive machines. I have read that a nice HAAS machine will give you in the range of 10 microns of accuracy in it's motion, right out of the box.

I think maybe we need to develop a calibration technique. I am baffled that for PCB machines etc. that this approach is not used - make a highly repeatable machine, then attach the spindle to a measurement device, which can be very expensive, a CMM machine, basically, and run a program that moves the machine around, and builds a table or set of polynomials or whatever, relating commanded position to actual position. Such machines, instead, appear to be made from extremely accurate and therefore expensive components that are laboriously assembled in ways to reduce error stack up.

I know this won't help with some issues, the spindle axis still has to be square with the z axis motion, the runout has to be ok, things like that. But it would help a lot. And yes in reality tool deflection and wear and so on all matter ( I also aim to get a tool change spindle, that's another case where I am muchly frustrated by the lack of foundation, however you can buy tool changers for 3040 and thereabouts sized machines through alibaba, they are just pretty expensive and hard to source).

Anyone else with me, wanting a more accurate machine? How do you hope to go about it/ have you gone about it?

I think we have a real problem in society where people see they can't really do things, like make accurate parts, then they don't demand it, then the market doesn't offer the tools to do so, then it just gets pushed out of imagination. We need to move forward. Demand higher accuracy machines, to open the doors that we can see will open when mechanical engineering can be really acted upon, the concepts made real, have their potential realized, becomes more accessible and widespread.