Router Issue/question anyone seen

[Mark Ottenheimer]

Hi All,
I have a question about an issue I am hoving with my router table. I have an older Hitachi 3HP plunge router in a home built table. Llately every time I go to cut any thing using this setupo the bit is rising while in the router. To describe better if I cut a cope for a cabinet door the first cut is perfect but second and third cut will be significantly off from the original setup. The router is locked and not moving, the bits are actually climbing in the collet.
Has anyone seen this before, or have suggestions on how to fix? I have been tightening the collet same as always and this has only started with in the last few weeks.
Thanks,
Mark

[pat warner]

Cope & stick cutters are stuck on the stock!
Present cupped or bowed stock to the cutter and it will try to pull the cutter out of the collet!
Old tool, perhaps bad depth adjusting hardware is slipping. burr on the cutter, crummy work, loose cutter, worn collet, undersized shanks. Lots of possibles.
Rout no more until you have this pegged. You could wind up a statistic.

[Jason Beam]

Make sure you're not setting the bit down into the bottom of the collet - make sure it's at least 1/16" up from the bottom - it can be a bit of a juggling act with some loose collets, but this is a key thing to be sure of. The action of a collet is that it actually pulls the bit down a little bit when it's tightened and if you have it bottomed-out, it can't go anywhere and thus the collet doesn't get as good a grip on the bit. Some folks stuff a little rubber O-ring down there to ensure they never hit bottom.

Also, don't be shy with those collet wrenches. Really snug 'em down good. I like the dual-wrench type that let me get two wrenches in one hand and i SQUEEZE 'em good 'n tight.

If that don't work, maybe you got yerself an undersized bit? Not likely, but possible. Another consideration is if the collet has some debris down there it can muck with it's closing capabilities.

[Norman Hitt]

In the past, a few folks have had that problem and found that the collet just needed a good cleaning with denatured alcohol, so add this to the list Pat gave you.

[Joe Scharle]

Collets get packed with dirt and they actually wear out, loosing their grip.

[Michael Trivette]

check your collets regularly.
they can be damaged and you wouldnt know untill you look closely.

If there is no damage a good cleaning and remembering not to bottom out your bits should help.

[Cliff Rohrabacher]

What Pat said, And ya might try a little more oomph when tightening the collet. Chances are it isn't tight enough.

It never hurts to take a micrometer to the shaft of the router bit.
It the thing was ground under-size most collets won't get a real good grip being able to only bring a few points of contact to the party.

How much undersize is tolerable? Well that'd depend entirely on the sort of collet you have. Not all router collets are created equal. Some are patently horrendous examples of engineering sloth and lack of thought such as the collet on my Triton Router, others such as those on my PC 690 and Rigid combo base kit are fabulous.

For the life of me I can't imagine the thought process that went into the name "Triton." In the Iliad, Triton was a monster who seduced children to the sea shore, dragged them into the depths having his perverse way with them, then eating them and leaving their bones on the ocean bottom.
Of course one has to read the original Greek language version to get that but, still.

[Greg Hines, MD]

I would add that you need to use feather boards fore and aft to keep your stock consistently down on the table for the long grain cuts, and a sled to hold the ends for coping.

Doc

[Howard Acheson]

When was the last time you cleaned the collet? Periodically it should be removed and cleaned in lacquer thinner or acetone. Use some 600 W&D paper and lightly clean the inside surfaces.

If that doesn't fix it, clean the shafts of the bits as above.

Finally, if they continue to slip, get a new collet.

[Mark Ottenheimer]

Thanks for the quick and detailed replies. I do not think it is the bits as I have had the same problem with others including high quality like freud. I will take the collet apart, inspect, and clean it thoughly.
Thanks again,
Mark

[Darius Ferlas]

I had the exact same problem about a month ago with a stile bit. The bit would rise gradually while I was routing. I lost a nice piece of cherry and an hour of work. In my case tightening the collet did the trick.

I always press the shank all the way into the collet and then pull it up is a hair. I was told that not setting a bit deep enough into the collet may cause the bit to go up, even if the collet around it is tightened well enough.