[Cartierusm]

Ok, so my CNC is working great, but I have quite a bit of run out on my router -- maybe 1/64" somewhere around there.

So my question is how accurate are router motors, should the run out be very minimal or not? I mean since they are made for wood working am I being over critical with the accuracy of it.

I have a Porter Cable 690 motor, brand new from Amazon, I didn't check the run out and just assumed it was good. I just rotated a 1/2" ground shaft in the collet against a precision square and it looked good. This was when I first got it. I replaced my original one because of the same problem, I thought the old router was just....well old, I've had it about 15 years. Now I set up with a Laser center finder in the chuck and when I rotate it the laser dot does not stay in the center but shows I have a little run out. I haven't measure it but will tomorrow. When I chuck the laser center finder in my Bridgeport the dot doesn't move at all when I rotate the chuck.

I just want to know if that's normal or if I get a different brand of router will I have the same problem. It's weird though it seems when I router something the tolerances are within acceptability for wood working, but I need the accuracy in set up because I'm cutting the same part at different stages of construction so I need to mill something then remove it change the position and then re-setup to mill a different area.

[ger21]

I think you'll find that the runout will vary from router to router within the same model, and you'll see the same thing regardless of the manufacturer. You could look through woodworking magazines and find some old reviews where they measured the runout, but I still think the runout will vary due to somewhat loose manufacturing tolerances.

[klick0]

Could you post a link to where you got the laser center point device? I'd like to check the same on mine. I have a Makita router, the 2 1/2HP version, i think it's pretty common. It seems very solid, but then again i've never measured anything on it.

I would wonder what the movement of the collet is under load (side to side), i would think that would be the all important test, albeit impossible to test.. I'm sure someone has the equipment, but i sure don't.

At this point, my current machine is no where near accurate enough for me to even start looking at the router, however i'm building a new machine, and this may become an issue after it's complete.

Ross

[LeeWay]

The armature on the router itself may not be the culprit. It might just be the collet. I use the same PC router with no runout with either the 1/4" or 1/2" collet. At least none that I can tell and I have milled aluminum with this one many times. Runout would surely show there. You can try ordering a new collet or have PC replace yours under warranty. That much runout is a pretty good bit.

Ger is right though. I do think it runs different from router to router regardless of make. They should be better than what you state. My Father in law bought one from HF and it has that much runout. He, however is happy as a clam with it because of the price.

[Cartierusm]

Klick, http://www.lasercenteredgefinder.com/

[BobF]

I have not tried to measure mine. I have a Milwaukee router. I use a V bit for many things. I have one that is 1/2" solid carbide that is 3" long and has a very sharp point. Wouldn't you be able to see 1/64" of runout?
I can cut a very line with this bit, so I don't think the runout is as much as Cartierusm sees in his.
I have a dial indicator. Would measuring against the bit at the last round part of the shaft be an acceptable method of measure?

[Cartierusm]

Bob, yes dial indicator is the way to measure. I measured mine today. My shaft is off .001 which I'm sure is well within tolerance, but as LeeWay said it's my collet that's off. I have 2 of each collet so I tried them. With my dial indicator they were off .003 and .0035. So I know it's not the router body. But it makes no difference I just rotate my laser center finder until the dot is lining up where I want it. I milled some pretty accurate stuff and the .003 doesn't seem to really afffect it. Thanks for the input guys.