I would demand and expect my 1/4" drill bit to not wobble in my drill
press. I realize that the RPM is higher on the router, but the
principle holds true. Maybe I'm just lucky as I've not ever experienced
what you reference. I still suspect that the bit is bent as it doesn't
take much as you move the router around, lay it on its side, etc. I had
a buddy buy some cheap router bits - total waste of time and money. I
have mostly 1/4" shank carbide bits, I expect to pay $20 -- $30 per bit,
I have them resharpened, some are over 20 years old and still work fine.

On 2/18/2015 7:10 AM, Electric Comet wrote:
On Mon, 16 Feb 2015 14:19:48 -0500
"dadiOH" wrote:

It is a plain old straight bit. The presence of a bearing is not
significant unless the bearing is unbalanced or loose.

right, that's the point

I've never even heard of - let alone seen - a 4" router bit with a
1/4" shank. If such exists, I sure wouldn't want to use it. For
that matter, the longest cutting edge on my 1/2" shank bits is maybe
3".

right that was the point, more an exercise or example that I
intentionally exagerrated to make the point


Even a bit that long (4") should run true if it is round and if
properly seated in a collet that isn't screwed up.

you say should but I say wouldn't
find some 4-inch x 1/4-inch diameter stiff rod and rev it up