[R Sitter]

What exactly is router runout...from reading I think that it has something to do with the tolerance between the shaft and the collet. But not sure exactly...

 

[delroy33]

if you were to setup a dial indicator and place the bezel (tip of the indicator) on the router shaft and set the dial to zero and rotate the shaft by hand, 360 degs and the dial indicator never moved, that would be zero runout.

now with the same setup and set on zero you rotate the shaft by hand and you have a TIR (total indicator reading) of say .020 (twenty thousands). that would be the runout on that shaft.

 

[R Sitter]

So it is ... to say, that the shaft is out of perfect round...

 

[Cummins92]

So it is ... to say, that the shaft is out of perfect round...

The shaft can be perfectly round(within 50millionths) and the ball bearing that it runs in can be running eccentrically. A good spindle(router shaft) should run within .0002 of and inch total indicator reading.

 

[GregLittleWoodworks]

I have 3 Musclechuck collets on 3 different routers...2 are in tables, a Bosch 1617 and a PC 7518 and the 3rd is in a handheld Milwaukee router. I have never measured the run out but have only used my centering pin but I have had not had any problems or concerns with the results I get.