RATTMMOTOR CNC Spindle Motor Kit Brushless 400W Air Cooled Spindle Motor ER8 12000RPM+600W Brushless Spindle Motor Driver Controller+55mm Spindle Mount Bracket for Mini CNC Router Engraving Machine

I don't leave many reviews but I felt the quality of this spindle warranted one. The first thing I did when I opened this up was to put it on the bench to measure the spindle runout. I would have been happy with if it was less than 1 thousandth of an inch.I first took out the collet and measured the runout on the inside of the taper. With a thousandths indicator the needle did not move at all. I cleaned out the taper and the collet and installed a new 1/8" endmill and measured the runout ~ 1/2" from the collet and again saw zero movement on the indicator. At first I thought the indicator was sticky or something so I tried another and got the same results. I don't own a tenths indicator but I would guess that the runout would be measured in fractions of a ten thousandth of an inch.The controller works smoothly and the PCB looks to be of decent quality with a nice big heatsink on the mosfets. The spindle is fairly quiet when running. I'm running this from a 36V power supply and get 9600RPM WOT.The documentation is not included in the package but the link provided is adequate and if I were so inclined I could easily configure this to be controlled this from the CNC controller. However, I prefer to set the speed manually.I am running it on a machine similar to the Nomad 883. For most people running a hobby cnc router built from aluminum extrusion and belts for positioning this is almost certainly a better choice than a palm router. With the flex of the extrusion and stretch of the belts you'll never be able to use the 1+ HP of the router, they are super loud, and the low end of the RPM range is usually around 8k-10k rpm which means you'll struggle to dial in your feeds and speeds appropriately for many materials.The only gripe I have about this kit is the extension cable for the LCD is only 4 or 5 inches long. It would be much better if it were 3 feet long or so.

I sent the first motor back and ordered a replacement motor. The reason was I thought I had a bad unit due to the lack of any start-up torque whatsoever. I got the second motor yesterday, hooked it up and again, NO STARTUP TORQUE.

The runout is amazing on this thing. Massive upgrade to my cnc router IF I can fix the overheating problem. So far I've snapped a 1/16in endmill because it just randomly stops when it gets hot. I'll be ordering a water pump to see if I can rig up a water-cooled system for this thing.

So far so good. Very little runout in the actual shaft collet area. Unit shipped with a 1/16th inch collet instead of an 1/8th inch which is fine but not as useful. Would have been helpful to note which size collet is included as decent ER8 collets are not as easy to find as er11 or larger. In fact, I've had a difficult time tracking a quality er8 1/8th inch collet down. Regardless, all is as advertised and I highly recommend these for PCB milling/engraving.Update 4/8/18:I bought one of these:https://www.amazon.com/Amana-Tool-CO-442-Inch-Collet/dp/B00O4TJ6TY/ref=sr_1_1?ie=UTF8&qid=1523168862&sr=8-1&keywords=amana+er8+colletI was hoping to buy a Techniks collet as their TIR is slightly lower but I did some tests and the runout is very low on the amana.