(Gleaned from the Router Jigs and Techniques with Bernie Maas and
Michael Fortune video tape Taunton Bools & Videos ISBN 0-918804-60-4)
Seating a router bit in the router collet and tightening the collet nut
is pretty straight foreward. Then you’re depth of cut setting starts
changing, getting deeper with each cut, especially with a dovetail bit.
You clean the collet and the bit and try again, this time making sure
the bit is fully seated and REALLY snug up the collet nut.
You route some more dovetails and things seem to be ok - ‘til you put
the parts together. The fit is close between the half pin and adjacent
tail and then gets worse acrossed the parts.
Here’s what may be happening.
If the bit is inserted ‘til it bottoms out, vibration while routing will
cause the bottom of the hole to “hammer” the bottom of the bit up, no
matter how much you tighten the collet nut.
Solution: Seat the bit to the bottom of the hole, then raise it 1/16th
and then tighten the collet nut
|| || NO. Bit bottomed out in hole will hammer
|| || itself loose in use
|| || YES. Bottom of bit at least 1/16th inch
|+--+ | above the bottom of hole
just something to think about