So I built my machine about 8-9 months ago and have put a few hundred hours on it at this point and wanted to share my experience and thoughts on the machine, the parts I picked up, in hopes that it will be helpful to someone. I'm actually in process of selling this machine to upgrade to another.

Machine details:
- 1515 / 1500mm x 1500mm (i.e. 4ft x 4ft or actually 48.25" x 50.25" working space)
- QueenBee Pro mechanical kit from Bulkman 3D
- 1.5kW 110V ER16 24K spindle from G-Penny (i.e. BEST Technology CO)
- 4x Rtelligent 3Nm Nema 24 60A3ED Closed Loop Motors with T60 drivers
- 48V power supply for motors
- Masso G3 controller
- routed 4" dust hose
- sound proof enclosure using mineral wool sound proof insulation and 2x4 with drywall construction

Thoughts on Performance:
- at 1500mm long, the gantry is not nearly stiff enough and should really use at least 50x100 extrusions or bigger, as opposed to the 40x80 they use
- I have to limit the speed and force on the spindle, otherwise the gantry twists. cutting at 4000mm/min (about 150 IPS) and 3/16 depth of cut with a 1/4 end mill produces pretty decent results
- Y axis works just fine with 4080 and I didn't notice any issues
- 8mm lead screw is: a) too thin and whips around too much, and b) is wearing out the Delrin nuts pretty quickly
- have to limit rapids on the machine to 5000 mm/min (about 200 IPS) to limit screw whip
- the 3Nm motors are crazy powerful and can probably push the machine to double the speeds I have it at now
- spindle has been great, no complaints. plenty powerful enough
- controller is great - I love not having to have the computer nearby and have had 0 issues with it

Support received:
- Bulkman 3D has been good in providing support, though I didn't need much from them
- G-Penny / BEST Tech has been good but very slow (I recently had a vibration issue when going above 18K RPM and it took a few weeks of chasing to get updated VFD settings to resolve)

Lessons learned:
- I bought the Nema 24 motors for their low 1.8 mH rating... should have stuck with Nema 23 as I had to manufacture the adapter plates and adapt the design a bit
- closed loop hybrid steppers are absolutely fantastic - I can easily stop the motion with my hand when in open loop, when in closed loop the steppers just move my hand out of the way no matter what
- 8mm lead screw is too thin and not accurate. Highly recommend you consider the "QueenAnt Pro" machine or upgrade from Yuyong Industry, though I don't have any experience with it
- replace the X axis extrusion with a much stiffer one if you're going for 1500mm long span
- soundproofed enclosure goes a LONG way... highly recommend

I use my machine mainly in plywood and hardwood - works great. I was debating the QueenAnt Pro upgrade along with some way to stiffen the X axis extrusion, but decided that purchasing a reliable welded steel machine with ATC and vacuum table already built in is going to save me more time in the long run.
I would still recommend this machine, especially when knowing it's limitations and being able to work with them. I still use it on a regular basis and will continue to do so until I sell it for the upgrade.


Let me know your thoughts on my build, what would you have done differently?
And if you have any questions, please let me know - happy to help.

Build photos:
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