First build, are these parts worth it?

[AutoWiz]

For quality you need a rigid frame. First and foremost. Then the more physical steps per mm of movement on each of the axes you can create will directly translate to increased resolution. You can drop the nozzle size down to 0.25mm get an extremely rigid frame and rail setup. Because 200 or more steps per mm of movement requires extremely tight tolerences for that kind of accuracy. One way I rework my printers is by bracing the axes on the frames in careful ways that bring about incredible amounts of rigidity to my machines. Here watch this: Multi Widow Rigidity Test - YouTube . That printer weighs a metric ton and I caught so much hate for removing the top brace from the Black Widow printer. But man is that rigid, right? So for the i3's I made these reinforcements: Geeetech i3 - Stability Rework by AutoWiz - Thingiverse . And then the resolution upgrades actually yield results. I went the other way with the Multi Widow, btw. I got it super rigid and went with big instead of small. 0.6mm nozzle and 0.5mm layer heights. I can print a 2x size benchy in the same time my i3 can print a standard benchy and that is just awesome by my standards. And I am aiming for a 0.8mm nozzle and 0.6-0.7mm layer heights for my TronXY X5SA 500 PRO.

[engpro]

I apprichiate the great information I am extremely happy with the resolution of my printrbot simple metal, so if i can achive that i will be happy with this build.But i wonder on this wanhao d9 400 mark 1 auction what would be a good price, right now. I beleive nothing is broken, just the z axis refuse to calibrate proper he said.I learn allot about the potential, you can even print bearings and use soft airgun pellets inside, amazing!wanhao d9 400 mark 1 does seem to have a really rigid frame and a big bedsize, and the steppers look solid, thats why this auction was appealing to me, but i feel i should limit to not buy over 150usd, what would be a reasonable price for one that requires some mantance?