Sorry, Bill. I was definitely referring to the Carbide 3D HDM machine specs that Patrick kindly linked to. Should my spindle fail, I’ll be heavily considering the option of retooling with a 1.5kw spindle with an ER-20 collet from C3D (if my interpretations are correct.).
My issue with 800W spindle is that’s likely peak power at full RPM. Back in the MPCNC days, I had the 500W chinese spindle. Putting a Makita trim router blew that thing away.
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The SOPro is more capable than the trim routers available. The SO3, even with the HDZ was pretty exactly matched with trim routers. I can pretty easily bog the router on my SOPros and SO4 enough that it limits how hard I can push before I skip steps because of the steppers.
An 800W spindle is roughly half the power of a trim router…I would not recommend it unless you just want to reduce noise. I consider a 1.5kw with a ER-16 to be perfect for a SOPro/4. But that’s a rare spindle, so an ER-11 at least runs 1/4" bits/mills and is really available. If you can find it in a 65mm body… even better. 1 5kw is also right at the weight that a HDZ is recommended.
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How does the maths for this work? The recommended Makita is rated at 1.25HP which google says is 932W, but some specifications when you try to buy them (not reliable I know) say the Makita is 710W. Other trim routers similar to the carbide 3d one have power ratings in the 700 watt range written on them (on paper).
Is there something different between the two when considering the motor type?
I just ordered this VFD and spindle. 1.5KW ER11 Air cooled spindle motor 220V/110V Diameter 65mm 4ball bearings Spindle for CNC Machine & 1.5kw HuanYang Inverter VFD|Machine Tool Spindle| - AliExpress I went with air cooled since I did not want the hassle of setting up a water pump and lines. I ordered the 110V version. They also have a water cooled spindle for $95.00 US which I might order in the future if the air cooled version does not work out.
I searched for setting up the VFD with Pro XXL and could not find any wiki or info on the subject. Does anyone know of a good instruction video showing how to hook up the VFD to a Pro XXL?
Here is the link to the water cooled version. 110v 800w ER11 CNC Water Cooled Spindle Motor Wood Working CNC Milling Spindle Motor 65x195mm With 4 Bearing|Machine Tool Spindle| - AliExpress
Thanks
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Looks like you’re right on the math. Must be some cobwebs in my head. 
But still a downgrade in power when on a SOPro the trim router is the limitation, not the November system.
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I haven’t hit the limits of my trim router yet on my PRO. I can get chatter doing adaptive clearing with a 1/4" 3 flute at 6mm DOC. If the router were the limit I would hear it start to bog down? This is at 27,000RPM, so a spindle I’d probably need to run slower since it maxes out at 24,000RPM.
Regading the motor power there’s a few things to bear in mind.
Universal motors (general AC routers) have zero torque at max speed and their torque rises to peak at motor stall. They tend to have high available RPM and used to be the cheap option.
Brushless DC motors are taking over from universal now, they have more of a straight line from peak torque at zero speed to max speed, zero torque. Peak torque also tends to be higher.
The problem for both BLDC and Universal motors is you can’t generally use the peak torque for very long as their cooling fan tends not to work very well at low speed and at close to zero speed the universal motor will over-current and let out the smoke pretty quickly.
BLDC and Universal are closer to constant power than spindles.
Spindles, especially on a VFD have pretty much constant torque from very low speed so you get less power as they slow down (torque x RPM) but they have a very wide smooth band of torque to exercise.
Spindles, esp. water cooled don’t have the same cooling problem as the VFD limits peak current to avoid burning the motor and the power is lower at low RPM anyway. Some VFDs can push more current at low speed for a short term torque boost.
Spindles also tend to have better efficiency than the universal motor type cheap routers so for electrical Watts in you get more mechanical HP out.
There’s a graph from Groschopp which does a nice job of showing the shapes of the torque, speed curves.
Ignore the relative torques of the motor types on the graph, that’s describing their project range, the shapes of the curves are what’s relevant.
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I’ve made the routers bog (nearly to a full stop) on my machines in walnut at 200 IPM. On the ramp-in when it is basically a slotting operation, I actually had to slow it down to 150IPM until it got the first slot out of the way, then I could bump it up to 250IPM before it started bogging with 75% stepover and a 0.250" DOC in the corners of the pocket. Feed optimization would help a little with that, but it seemed a good real-world use case scenario.
I also HAMMERED thru blatic birch at 400 IPM with the above settings and an upcut endmill. This was really just to test the machine more than make anything as the upcut made a splintered mess. It did 200 IPM with the same settings and a downcut before it started bogging.
I have also made it bog cutting HDPE at 400 IPM with basically the specs above except at 0.125" DOC. I had to run a large batch of some parts, so I was pushing as fast as I could.
That is repeatable on 2 SOPros and a SO4, so 3 different routers. And yes actually does hit 400 IPM with the distances and accelerations (well, 393 IPM since the grbl default is a max of 10,000 mm/m).
Super jelly. I’ll get a video next time, but I’m doing adaptive at 3000mm/min, 6mm DOC, 1.9mm optimal load - 1/4" 3 flute up-cut - and I get chatter in Maple.
Not sure what’s wrong if I get that and you can scream at 400IPM doing slotting… Baltic birch is pretty tough with alternating layers of grain direction. I haven’t done that in a while but I was under 100IPM I think. Any videos? Curious how it sounds. I worry there’s something up with my machine then.
Search this forum, or ask @Julien, as there have been several very detailed discussions on configuring the two popular makes of VFD.
I know I put videos up in the Unofficial FB group. I’m see if I put them here. 
The baltic bitch shred fest was fun to watch.
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Ah I think I remember that on FB. Now finding it on the other hand
Edit: is it the I Like to Boogy one?
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That one is 200 IPM with the “Jenny” compression.
The one I’m referring to is here:
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Wow that’s insane. Yeah my shudder is far worse.
Can I ask you/others, when you put your router in the mount, how was the fit?
I noted of the middle set screw to help avoid scratching things up. Mine was not needed by FAR. The router slips in easily, drops right to the bottom. I then have to tighten the HECK out of the bolts on the 65mm mount to get it to even start gripping my Makita.
The only other rigidity issue I can think of is that my spindle is trammed with feeler gauges since there is no other way to do this.
On the four SOPro/SO4’s that I have assembled or helped on, 3 were slightly loose before tightening and didn’t require the grub screw to open them. The 4th was almost a perfect fit without the grub screw. My strategy for tightening the mount is to alternate between the two screws to avoid cranking too hard on one.
I used shims to get the nod, or fore/aft tram dead-on. Multi-million dollar machines use shims to get the tram dialed in, so it’s a valid method.
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In that case, wanna trade Pro’s?
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