Dangerous practice Collets in routers?

[Taffy]

Guys
I have a problem with using a reducing collett in my 1/2 inch router, I have had a couple of experiences with the 1/4 " bit climbing out of the chuck, this has happened since I first used such a device, is there a particular collett to use? has anyone had the same problem and if so how did you fix it. I am not a great fan of slipping shims into revolving machinery and need to feel that it is a safe practice before I do some damage to the tool or myself.
Is it just possible that I had a poor collett from the start and am judgeing the practice harshly.

Any help would be appreciated.

Taffy
:(

[journeyman Mick]

Taffy, the reducing collet should be the one supplied by the manufacturer and should therefore (supposedly) fit. Are the shanks of your bits clean and free of rust and burrs? Any irregularites on the shank will prevent proper grip. Also check the inside surface of the collet for same. The only other time I've had trouble with bits slipping down was during heavy cuts in hard timber when the vibrations loosened everything on the router - all the wingnuts holding the fence in place, the depth stop adjusters etc. etc. If none of these are a problem I might be getting in touch with the manufacturer or their agents.

Mick

[Taffy]

Thanks Mick,
On inspection I have found that the collett is ribbed inside, probably from the bit climbing out in the first place. I rang carbatec and took the offending piece in for closer inspection and the bit I was using at the time, and hey presto the collett was at fault, I have purchased a new one that looks and feels better (CMT). it fits better and hold the bit without slipping. and you were right the guy at the tool shop said I should clean the collett and the bit shafts before use as any bit of junk inside would stuff up the equipment.
One correction to this reply, it was the missus that went to carbatec with the gear as I could not get there until the weekend.:)

[Eastie]

I recently bought a cmt 45 degree chamfer bit in ¼” shank - the only ¼ inch I’ve ever bought but I couldn’t get hold of a ½” shank. I’ve used them before but never purchased them for reasons of being sceptical about strength.

Anyhow following 25 metres of continuous cutting in a TR12using the original reducing collet I stopped the router only to have the 1/4 “ bit fall straight out of the reducing collet on to the floor. To say I was surprised is an understatement, as I never under-tighten – in fact I over-tighten on purpose and service the collet regualrly. The chamfer was only 3mm in relatively soft messmate - no abnormal vibration or anything.

I checked it out, replaced the reducing collet with one I purchased from carbatec along withthe the bit and cautiously tried again – again done up as tight as is possible. Less than 1m of cut and the bit had slipped down 3mm. Two reducing collets, the router collet and the bit all appear perfect even under low magnification.

The collet has never shown any sings of this problem before – nor since using other ½” shanks including a 2” straight bit ?

(PS if anyone picks it - don't ask why. Just remember I'm an 'expert' :D :rolleyes: )