bits not tight in router - why?

[dspeer]

I have a router table setup consisting of a jessem-em table and lift with a milwaukee 3 1/4 hp router mounted to it. 

I noticed that something wasn't right when a roundover bit with a 1/4 inch shank moved upward while routing, screwing up the workpiece.

I went through the tightening procedure multiple times and felt something was wrong. When tightening the collet, I was used to stopping tightening when I felt it was tight enough. With more power I would have gotten it tighter. Now, at some point, there was something like a 'hard stop' an what point I couldn't have possibly tightened further. As if the shank wasn't thick enough.

Now I seem to encounter the very same thing with a 1/2 " bit: A 'stop' position while tightening and a bit that seems to move up slightly. 

The router is about 10 years old, so are the collets. 

My question: I can see that collets might get 'tired' after a while - but both at the same time? Are there parts of the router shaft (that the collets screw onto) that might cause something like this?

I am not using anything but 1/4 or 1/2 inch bits, no weird european sizes.

Thanks for any help / opinion

Dietrich

[fixtureman]

are you bottoming your bits out.  you need to leave them just a little up from the bottom so that when you tighten them there is room for the bits to pull in a little.

[Steve N]

Not only will keeping the bit off the bottom of the collet allow you to tighten the bit up, it will also be much easier to get a bit out when you go to change them.

Router table tips from Fine Woodworking Some of them apply to hand held routing as well.

Some from WoodCraft

Never too many safety tips


Print them out as a quick reference and keep them where you keep your router equipment.

[jteneyck]

I think you've got sawdust jambed up in the nut that is limiting how far it can be tightened. 

John

[dspeer]

I don't think I am bottoming them out, but I guess I might have to be more careful about that. 

Nothing known about any possible wearing out of collets or router parts?

[Downwindtracker2]

If that's not the problem, where the collet taper mates may be worn. I recycled a Craftsman for just such a problem.

[MikeBob]

I don't think I am bottoming them out, but I guess I might have to be more careful about that. 

Nothing known about any possible wearing out of collets or router parts?

Maybe time to get a new collet and nut cant be too much $.

[mike4244]

If you have access to a micrometer check the shaft sizes. I worked in a shop where we found that an entire set of straight cutters was undersized . This was a new set that was given to us buy our distributor for our opinion of the new line. We had our millwright mike the shanks after experiencing problems with slippage.
It is unusual for both 1/4" and 1/2" shank both to slip,different collets. If the collets are clean and the shanks are correct diameter ,I would buy new collets.
mike

[EdL]

I don't think I am bottoming them out, but I guess I might have to be more careful about that. 

Nothing known about any possible wearing out of collets or router parts?

Collets have a long lifespan if not overtightened on a regular basis.

Imo, you have a sawdust buildup.

Blow out everything with compressed air, wash with paint thinner  and make some test cuts to see if there is a difference.

Ed

[JGrout]

I don't think I am bottoming them out, but I guess I might have to be more careful about that. 

Nothing known about any possible wearing out of collets or router parts?

collets do wear out if A: over tightened 

B: bits are incorrectly installed

C:  Over used 

clean up all the parts with a simple solvent, check for sawdust, make sure the bits are not bottoming out and try again. 

If the bit still migrates swap out the collet 


 One more step clean the shank on the offending bit..... if it spun at some point it is is possible is has a glaze on it that makes it slip