I have seen questions about spindles come up relatively often on these forums and thought I would weigh in with some of my experiences. I have used the recommended DeWalt DW660, a 500W DC brushed spindle with an ER11 collet, and a Makita RT0701C Trim Router. I have tried to lay out some relatively unbiased pros and cons for each option below, but I will give my opinion here. The DW660 is definitely capable, but I think the Makita is a better option if you are trying to improve the performance of the MPCNC (without stepping up to much more expensive options like a VFD spindle or a Kress). It absolutely chews through wood and the lower RPM options make it very suitable for metal and plastics. I would not recommend the 500W spindle unless you really need to limit noise and are only planning for engraving and light cuts.
Price: DW660 (~$50) < 500W DC (~$75) < Makita (~$100)
Noise: 500W DC (59dB @ 12k RPM) < Makita (61-77dB @ 10-30k RPM) < DW660 (78 dB @ 30k RPM although the volume does decrease with a speed controller)
Power: Makita (780W) > DW660 (600W) > 500W DC (500W)
Weight: 500W DC (1.8 lbs) < DW660 (3.2 lbs) < Makita (3.9 lbs)
Minimum Spacing from Mounting Plate: 500W DC (30mm) < DW660 (~46.4mm) = Makita (45mm)
Collet Sizes: 500W DC (ER11 lots of options) > DW660 (1/8” and ¼”) >Makita (1/4” although there are some 3rd party options)
Speed control: Makita (10k-30k RPM) > 500w DC (5k-12k RPM) > DW660 (30k RPM or ?-30k RPM with triac)
This router works well, and I was able to easily cut wood and plastic, as well as a little aluminum.I hooked up a triac dimmer in line with the router to give me some speed control. I found that this helped to reduce speed and limit noise. However, this method definitely seems to limit the torque and I would often hear the spindle slow down pretty dramatically during heavy cuts if I had the dimmer below ~80%. This drop in RPM resulted in a rapid increase in chipload, exacerbating the problem and leading to chatter and some pretty gnarly cuts. This is can be completely overcome with careful CAM, but it does limit the material removal rate you can achieve. Overall, this spindle definitely has the most power per dollar and is a great option for the MPCNC, but the lack of speed control (could be solved by Ryan’s PID) limits its performance.
500W DC Spindle:
I work out of the basement in a house with a few roommates and I found that the DW660 was too loud to use many times after work. I purchased a 500W DC spindle on Bandgood and gave it a shot. This is far and away the quietest option, although everything makes noise whIle cutting. Right away I ran into issues with chatter. I found that I needed to drastically cut back on my feeds and axial and radial DOC, and even then I ran into issues with vibration and chatter. I initially blamed the chatter on flex in the z-axis, but after extensive tuning and redesigning mounts to get as close to the axis as possible (green mount below) I was still running into chatter. I should probably check the runout. As with the DW660, careful CAM can definitely overcome some of these issues, but I am just unsatisfied with the performance at this point.
Some additional discussion of this spindle including a documented teardown: https://www.v1engineering.com/forum/topic/500w-12000rpm-spindle-not-enough/
[attachment file=“Compare Spindle Mounts v1.png”]
I initially assumed that trim routers were too large, and would stick out too far from the z axis, but after picking this model up at the hardware store I was impressed by the small size. All of the mounts on Thingverse seemed to space it needlessly far from the z-axis, but after a little CAD work I was able to get a design together (blue mount above) that puts it ~1.5 mm closer to the axis than the DW660 (red mount above). I have been very impressed by the power of this router and have been able to cut faster and deeper without any loss of RPM. This router is just as loud as the DW660 at full speed, but when you turn it down the noise drops off significantly and it is much quieter than the DW660 (even with a triac). The router doesn’t come with a 1/8” collet and they are pretty pricy if purchased from Elaire. This option allows me to squeeze a little more performance out of the MPCNC.