I tested the runout on my router and found it to be .011" out. I purchased some PreciseBits collets to see if that would remove it. It didnt. I spent most of this afternoon trying to shim the router to remove the runout. The best I could get is .005.
When cutting a 3X4 square the difference between the top and bottom of the cut is out about .008. I am at a loss as to what to do and am turning to you experts for help.
Any ideas?
Make a spindle square and adjust the router mount until it is perfectly vertical.
Do you know where I can see what a spindle square looks like?
The professional tool for doing this is a “Spindle Square” — the design for which is shown in danimal’s Forum post Making a spindle square. A field-expedient way to do this is discussed in the forums: Aligning DW660 to be perfectly vertical — mount a 1/8" diameter rod in the spindle and bend it with two right angles as shown in:
So I had another DW-611 in my woodworking shop for routing needs. I checked the runout on the bench and it was less than .001. I took the one off my CNC and checked it on the bench and still at .011. Either it was a bad job by Dewalt in their QC or the bearings got out of round somehow.
Just a heads up if you cannot figure out the cause of the runout, it may be the router and not the bit, collet etc.
Squaring your spindle:
Obviously I was very wrong in my assessment here, but very glad that @Bonch puzzled this out despite my misunderstanding.