G'Day from Australia! I bought myself a Workbee 750mm x 750mm screw version. About the set up: 1.5kw air cooled spindle with vfd - https://www.sharpsoftware.com.au/product-page/1-5kw-air-cooled-spindle-vfd Fusion 360 for cam/cad OpenBuild Control program using grbl, arduino, tb6600 stepper drivers. Steppers are 2.45Nm - https://www.sharpsoftware.com.au/product-page/nema23-stepper-motor-2-45n-m Cool mist system with oil/coolant mix as recommended by my local machine shop (120 psi air pressure to remove chips). I did my research and I expected that the Workbee would mill aluminium with enough preparation (watching ooznest YouTube videos have inspired me). I am only wanting to build prototype parts. This is not for commercial use. I plan on getting a working prototype and then sending the cad files to commercial cnc for production. But I have had serious trouble doing simple things with aluminium.I have had no trouble with MDF or plywood. And I was very happy until this point. I was able to get a part cut from aluminium using the absolute lowest settings - 100mm/sec feed rate and 50mm/sec plunge rate. I was making dust (which is bad I read) and the finish was not good, but it was passable for prototype - BUT the main problem here, was the time it took to produce the part - for one of the parts, fusion estimates 6 hours. I slowly sped things up but things got worse. I dont know what the problem is, but below are some questions/problems to help figure this out. Any help/advice for any of the questions would be appreciated. BITS?: I started with cheap 6mm 2 flute hss flat end mills with the intent on buying decent carbide when I get everything going. I have one 3 flute 6mm carbide bit which I tried after the hss failed. This did not seem to make any difference. First observation: All the bits seem to slide around the aluminium. Watching as the z axis comes down, I noticed that the stepper seemed to have enough torque, but the shaft adaptor was flexing so much that there was not much pressure on the aluminium. I have made sure that the eccentric spacers are adjusted properly. There is almost no play in the z axis in any direction, except when I pushed up the z axis with my hand, and saw flex from the shaft adaptor. First question: Am I using the correct shaft adaptor (came with kit) - is the flex I am getting normal? 6.35mm x 8mm Flexible Coupling - Maker Store Second observation: The backlash nut block on the z axis is supposed to be adjusted? I have not adjusted this at all because of the location of the nut (in between the z axis plates) and also because I dont believe I have any backlash. Second question: Does this adjustment also affect the torque of z axis coming down? Here are some of the setting I have used (none have created 'chips'): Tried this first: 10000 rpm (also tried slower and faster) 100mm/min cutting feed rate 100mm/min lead in feed rate 100mm/min lead out feed rate 50mm/minramp feed rate 50mm/minplunge feed rate 0.1mm pass depth and 0.3mm and 0.5mm Following fswizard calculator online version. 8000 rpm 833mm/min cutting feed rate 100mm/min lead in feed rate 100mm/min lead out feed rate 50mm/minramp feed rate 50mm/minplunge feed rate 0.1mm pass depth and 0.3mm and 0.5mm Following Ooznest Youtube Video: 16000 rpm 730mm/min cutting feed rate 100mm/min lead in feed rate 100mm/min lead out feed rate 20mm/min ramp feed rate 316mm/min plunge feed rate 0.5mm pass depth Thanks very much, Benjamin.