Today I was finishing up the carcase of a base cabinet of a two piece china hutch. I decided to add a subtle detail, a lambs tongue, to the outside corners of the face frame. I grabbed the Dewalt 621 plunge router and chucked up a 45 degree chamfer bit, set the depth just right and began routing.
The first corner looked good. I made a couple of passes on the second corner, and then on the third and final pass something went wrong. The chamber was way too deep. When I looked at the chamfer bit I noticed it dropped out of the collet (coming out), a lot. It left a very deep cut at the beginning of the chamfer. I checked the collet and it was tight and the bit could not be moved up or down in the router by hand.
I checked the shank of the bit for any oil, which was unlikely since when I received the bit, any machining oil was removed with solvent. Additionally I had successfully used the bit in the past. I re-chucked the bit and measured its depth. Then I turned the router for about 30 second under no load. When I re-measured the position of the bit, it indeed was moving out of the collet.
Luckily I had a spare collet, new in fact. I replaced the collet, chucked the bit and repeated the measurements. It held. I then recut the first corner at a much deeper depth than I wanted and cut the second lambs tongue with no further problems. Well except that the subtle detail was now a womping big lambs tongue - but the wife said it was ok, so I guess its ok.
Until now, I never gave a thought to the wear that can occur on a router collet, but apparently (of course) they wear out. Since I grab the Dewalt 621 toward the end of a project when a lot time has been sunk into it, I think I will replace the collet about once a year or so.
The first corner looked good. I made a couple of passes on the second corner, and then on the third and final pass something went wrong. The chamber was way too deep. When I looked at the chamfer bit I noticed it dropped out of the collet (coming out), a lot. It left a very deep cut at the beginning of the chamfer. I checked the collet and it was tight and the bit could not be moved up or down in the router by hand.
I checked the shank of the bit for any oil, which was unlikely since when I received the bit, any machining oil was removed with solvent. Additionally I had successfully used the bit in the past. I re-chucked the bit and measured its depth. Then I turned the router for about 30 second under no load. When I re-measured the position of the bit, it indeed was moving out of the collet.
Luckily I had a spare collet, new in fact. I replaced the collet, chucked the bit and repeated the measurements. It held. I then recut the first corner at a much deeper depth than I wanted and cut the second lambs tongue with no further problems. Well except that the subtle detail was now a womping big lambs tongue - but the wife said it was ok, so I guess its ok.
Until now, I never gave a thought to the wear that can occur on a router collet, but apparently (of course) they wear out. Since I grab the Dewalt 621 toward the end of a project when a lot time has been sunk into it, I think I will replace the collet about once a year or so.
