Collet loosens during use

[DRC]

I received a Router Boss 470 Digital last week. Also purchased the Mortise table and plunge assist. Got it assembled and mounted yesterday and my first cuts today. I had 4 walnut frame sides that I wanted to run a dado down the middle of 1 edge. I worked well on 2 of them, but something completely unexpected happened on the other 2. The router bit slipped down in the collet while cutting the dado. Ir was about 1/4” deep and I was routing out the next pass when I noticed the sound of the cutting became much rougher and louder. I flipped the router switch to off and in both cases the bit was almost 3/8” lower than where I had locked it down.

Something about the previous passes or the pass I was currently doing had loosened the collet enough to where the forces on the spinning bit had caused it to move downward.

Has anyone seen this before?
Any thoughts on what happened here?

Thanks,
david

 

[larry.thomson]

congrats on your new router boss -- welcome to the forum -- i will take a stab at your problem --

i am assuming you have the dewalt 625 router because you referenced the plunge assist -- i have not seen that issue with mine -- read somewhere that the a good rule of thumb is to insert 1" of the shaft in the collet and tighten down on that -- if you had enough shaft in the collet and had good tightening -- then perhaps it's a collet issue on the router or possibly the bit someway -- perhaps try with another bit, secure good, see if you can reproduce the cuts without incident -- and as you did, listen to the router -- it will tell you if something is changing -- let us know how it goes --

better days ahead ......

larry

 

[DRC]

Hi larry,
The router is a Porter Cable 890 with a 1/4" diameter 1.25" long straight cutter bit.
I had to do a slightly different installation for the plunge assist, but I think it's solid. I'll add a couple of pictures to show what I did.

I, like you, have never had a bit extract itself from the collet before. I did a little digging around the web and it seems that it is not terribly uncommon. Also, seems like the main reasons were 1) bit shaft or collet not being clean or 2) bit shaft or collet being damaged (scarred). I looked at both and I think the issue may be due to the collet being damaged. It had a lot of internal scarring on it. Amazon will be delivering a new collet today and I'll see if it makes a difference. I'll let you guys know what I find.

On a completely different topic, but something that I know is a known issue... I was able to fix the non-parallelness (is that a word) between the Mortising table and bottom of the Base Plate by putting an angle on the shims.
david

 

[larry.thomson]

looks like you have the issue under control -- on a side note, i was excited to see you were able to adapt a different router than the dewalt -- i think they have discontinued the 625 -- i guess i am pretty hard on the router because i use a collet extender quite often -- have replaced the dewalt once -- glad to see there is an alternative available --