I’m just starting out myself, but it seems to me that if you never intend moving to a larger spindle and for instance you never intend to (significantly) cut metal then I’d say go for the Z-Plus. Otherwise, to absolutely future proof your machine and you can afford it get the HDZ (but that might be a bit of a wait)
Relatively new user here as well and I personally own the z plus. I like it a lot, but the biggest drawback I have with the z plus is z travel. When I am using a small endmill, I cannot reach the top of my wasteboard. I have a 3/4 mdf board on top of the already supplied mdf baseboard. I’m actually considering stacking yet another 3/4 on top to eliminate this issue. That would be the main reason I would consider the HDZ over the z plus at the moment. If you’re also considering milking a lot of metal on it then I would probably go to the HDZ just to ensure you have a pleasant experience. I have not cut metal with mine yet so I can’t speak for how well the z plus will do in metal.
The step size is tiny and you’re right, compared to the other deflections in the machine the Z step size will not be relevant.
However… The Z plus uses a leadscrew and the HDZ uses a ballscrew, those two really aren’t comparable as the ballscrew is the one designed to not have backlash, lead screws have assorted after-thoughts to work around their inherent backlash. Still, other things on the machine will dominate.
You are so right. It was called vaporware in my day and referred to a company announcing a product or software well before they were ready to roll out the thing. This was often done because they knew their rival was announcing a new competitive product before them. This is not the case here, it’s the nature of the enterprise. Building a low cost but reliable cnc machine we can all afford. Still, I agree with you the wait for such gripes my ever-loving you know what. I want my toys when I want my toys, LOL. As for the choice between the two, to each his own.
That’s a pretty good explanation. The linear rails and ballscrew on the HDZ deal with the backlash with a similar preload mechanism, the bearings rolling in the tracks are slightly over size and therefore don’t wobble up to a certain load, nothing is truly zero backlash.
Just in case anyone is interested, I stuck a 0.01mm dial gauge on my HDZ and heaved it around with “large cutting force” i.e. about 5kg force up, down, left and right by the spindle and the backlash I measured between the spindle mount bracket and the fixed Z plate on this sample was;
X backlash - sod all, squat, couldn’t even see the needle move
Y backlash - as above, below my measurement capability
Z backlash - < 0.005mm
I think that exceeds any performance we would require of it on a Shapeoko, nice one Luke
I don’t have one to measure, hopefully somebody else does.
Bear in mind though that it’s likely to be a small number in the context of the deflections elsewhere in the machine from the V wheels and belts.
The stock Z had some relatively large unwanted movements which the design of the Z plus removes rather effectively, it has linear rails (like those on the HDZ) so that should be X and Y deflection taken care of and the leadscrew is going to be a large improvement on the old belt drive.