DW660 Runout?


First I’d like to thank Ryan for sharing such a great design, I’ve been wanting to build a CNC for a long time (actually purchased a set of plans forever ago, but never quite got around to it).

I have a 24"x30" MPCNC built and successfully cutting but have noticed - probably first when i played with milling PCBs - that my DW660 has quite a bit of runout…

After initially writing it off, I finally decided to dig out my dial test indicator and measured about 0.2mm runout about 10mm down from the collet. I tried a couple different 1/8"chrome shafts as well as various bits and they all measured about the same.

So finally my question - I was wondering if anyone else has tested the runout in their DW660, or if 0.2mm would be normal for this router?



.2mm is actually pretty good for a wood router.

Have you clocked inside the spindle, it maybe your collet.


I just checked the inside of the collet holder (as well as the smooth upper outside) and runout on both is pretty low - 0.02mm which is as good as i’d ever expect/need, so looks like my collet may be a bit ‘off’.

I remembered I had one 1/4" surfacing bit so i put that in and with 1/4" collet it seems better then my 1/8" - clocked 0.07mm runout on the 1/4" shaft.

I know for other routers you can get ‘precision’ collets, but nothing for the DW660 :confused: perhaps for now i can compensate in the CAM and order a new stock collet maybe my luck will be better on a 2nd one.


To put things in perspective, common or garden ink jet paper is 0.1 mm, as has been mentioned 0.2 is not too bad for a wood router, you won’t notice it with a single flute cutter, with more than one flute all it will mean is one flute will be working more than the rest depending on !
Feedrate - spindle RPM - dia of cutter - flutes - depth of cut, , there are charts and formulae out there.

The other thing to bear in mind but I don’t think it will be that noticeable is vibration, run the router with and without a cutter.


Don’t run the router without the nut tightened up !!!

It will tighten itself right up! Getting it back off could be an issue though.

If i’m running multiple finishing passes though on a soft material (soft pine in a recent case), wouldn’t you expect 0.2mm runout to equally impact the final dimensions regardless of number of flutes? i.e. the diameter at the cutting flutes i’d expect the bit to become essentially 3.375mm wide vs 3.175mm (I’m trying to see if i’m thinking about this right - still learning :wink: )

This said - practically I do seem to see more issues when using dual flute cutting soft materials like pine, I have been doing some aluminum work with a single flute and I actually don’t recall as much of an issue although now i’m going to go measure the aluminum brackets I cut for my 3d printer to measure them again to see :wink:

I’ve also had my eye on a Makita RT0701 (or DW611)- based on the internets at least with the combo of a aftermarket collet would be much better then what i’m seeing with the DW660 - but yeah in the end these are all inexpensive wood routers so it’s all a bit of a crap shoot, but I’m having fun playing…







With a single flute mill, you’ll have runout, but it will be the same for every cut. With a dual flute, each edge will have a different length from the center of rotation. This will cause little scallops on the cut since the mill is moving.