Router vs worktop - honours even

[Anonymous]

I used a 1/2" Trend Pro bit to cut a masons mitre (which looks perfect btw..yippee!). But I noticed that after the first few passes the Trend bit was making heavy weather of the worktop in comparison to the cheaper Freud Diablo that I'd used to cut the worktop in half. And by the time I'd got to the final pass on the male joint there was some vibration that wasn't there earlier. Examining the Trend bit's shank, it was badly scored - a ring just below halfway + 4 equidistant lines running down the shank to the bottom and which seem to be caused when removing the bit from the collet; the usual second stage loosening with spanner continued until I had the whole bit/collet/nut assembly come out together. There's now resistance to sliding the shank into the collet even when not in router, and it makes more such scratches. There's also a visible line around the interior of the collet. Presumeably I should get a new collet? But I can't get it out of the nut. The DeWalt manual simply says "pull firmly", but I've pulled it has hard as I can grip with no success.

Btw, I thought that a bit was supposed to be inserted into the collet as far as it goes and then back out a few mm, but it could go all the way in on this DeWalt 625EK - well beyond the shaft web. The depth mark on the Trend bit is about half way along the shaft - but it needs to be there to achieve the necessary depth for a worktop.

Just to point out, I did clean the bit and collet before use each time. I must have undertightened the nut with the Diablo because it came loose a couple of times. But its shank still looks ok.

Square

 

[Chris Knight]

Square,

From what you say, the bit must have been spinning in the collet (hence the ring) and that in turn has raised some parts of the shank, or collet that scratched the bit when removed.

The 625 collet will come free from the nut - usually with hand pressure but if not enough a pair of fine nosed pliers , gripping one side of the collet and tugging, should certainly be enough. I guess it's possible that if the collet also spun, then damage may have been caused that prevents this.

Why the bit came loose, I don't know. If you only had a small amount of shank inserted, that is one possible reason, dirty collets as you have recognised, is another. Are you sure that the Trend bit has a depth mark for insertion? In my experience, very few bits have such a mark.

The fact that the Diablo bit also came loose a couple of times suggests there is a problem with tightening. If you are sure you inserted the shank sufficiently far, then it sounds like a faulty collet or nut or possibly the diameter of the hole in the motorshaft that receives the collet.

It's rotten luck but I think you will have to junk the collet and you should get the shaft looked at before spending money on a new collet. This should be clean and bright obviously but also of the correct (critically so) dimensions and since it is tapered, these would be difficult for you to check yourself.

 

[Anonymous]

Regarding depth marks, the packet for the Trend bit indicates it should be inserted at least 2/3 up the shank, and what I think is a depth mark (straight line with a "V" on top) is 2/3 from the bottom (not half way as I said earlier) so I think that's what it is. The Diablo pack does actually say there's a depth mark on its shank, but I can't see one. Looking at the circular groove in the collet, it would coincide with the bottom of the shank with the bit inserted to the 'depth mark'. So hopefully, my depth would have been acceptable. But I assume the mark is a 'minimum depth mark'.

Now you've drawn my attention to it, Chris, I can see that the inside of the shaft has some length-ways grooves at: 3,6,9 and 12 o'clock. That's coincident with the edges of the 'segments' of the collet. The collet does have a couple of touches of rust on it too. I'm thinking that this is the collet's fault not mine. Am I right...should I send the router back to DM-tools? I really need to cut the bolt recesses for my worktop, so I think I'll have to sacrifice the Diablo bit too, i.e. let that get grooved up as well to finish the job, and then send the it back. Anyone know if I can ask for a replacement?

I tried gripping the collet with narrow nose pliers through tape, but couldn't get it out. I gave up becuase I don't want to score it anymore if it's got to got back.

Worth mentioning that the DeWalt's 30 mm guide bush is unusable - it's got a groove around part of the circumference and it's base isn't flat. The 'measuring lens' doesn't slide properly and keeps jamming too, doesn't seem to improve with use either.

Square

 

[Chris Knight]

Square,

You could try another collet but they aren't cheap and you may have no more luck with that if the motor shaft is to blame.

I agree that your mark does sound like a depth indication (ie a minimum) having said which I frequently let my bits protrude far farther than recommended (as the gardener said to the art mistress) .

I am puzzled that you can't get the collet out too - it suggests some possible spalling between collet and nut to me.

All in all, I would send it back I think. At the least it is going to cost you money in its present state and it may be positively unsafe.