My new Milwaukee 5625 shudders

[Wade Lippman]

I just finished building my router table with a Woodpecker Sidewinder and a Milwaukee 5625.

I put a 3" long bit in and turned it on. When starting and stopping there is a visible shudder at the end of the bit. It has a bearing there, so I held a piece of wood up against it. At speed it feels smooth, but the first split second and just before it stops you can feel a significant shudder.

Is that normal? I don't want to be a crank and complain about something normal, but this doesn't look right to me.

If the router bit wasn't straight, it would be bad as speed, so I figure it has to be the router.

[Myk Rian]

Are you sure the bit is straight?

[pat warner]

I smell a (bearing) rat. Take the bearing off the cutter and try again.
Still vibrating? Pull on the cutter, any axial play? Any side play?
No changes? Try with no collet, still the same vibration?
Then probably some arnature bearing slop.
Not the bearings themselves but how they sit in the casting.

[Richard Coers]

Try a different speed, sounds like it is hitting a natural frequency. Or, turn down the rpm's before shutting it off or turning it on. That router is not a really big unit, and the bearings are not as far apart as other high hp models out there. Might even be some smaller diameter bearings that don't like that long of bit. Contact Milwaukee for a bit size recommendation.

[Joe Scharle]

I'm intimate with 3 of those and what you describe is not normal. But I would mount a big panel raising bit and see if it's router or bit.

[glenn bradley]

I think Pat and Joe nailed it. I have a couple 5625's and they are like glass. A 3" long bit is a stretch for any maker but, I run a 3" long by 1/2" diameter Freud without issue. A "bargain" 3" long bit I would avoid. As mentioned, try it without the collet on. Any shudder should still be visible under good lighting. If that looks good, add collet and re-test, bit without bearing and re-test, and then bit with bearing and watch for the behavior to show.

[Wade Lippman]

Okay, not normal.
I contacted Milwaukee; they agree it is not normal, but think it might be the bearing.
I tried it on another 3" cutter; it looked fine, but there was nothing constant to look at.
I tried a 3.5" raised panel cutter. I "think" it shuddered, but it was not as conspicuous as with the first cutter.
Both are Frueds, which I think are pretty decent, aren't they?

I then measured the run out. With the rpc it was 4/100ths.
With the big straight cutter it was 8/100ths
Neither one showed any run out when I turned the bearing; just when I turned the bit.

Finally I used a 1/4" collet with a 1.5" long straight bit with a bearing.
It had run out of 5/100" which is consistent with the other two.

I am assuming that that much run out isn't right...
Back it goes.

[glenn bradley]

Good testing there Wade. You could also chuck up a high quality 1/2" drill bit and test against it but, I think you have got it nailed down at this point. Exchange time.

[pat warner]

50/1000ths!!!! Yikes that's a country mile in RouterDom. Do not turn that router on again.