Potentially humiliating OF 1010 question

[John Stevens]

You don't need to tighten a router bit very tight because the rotation induces tightening. The same is true of the Domino. Over-tightening the Domino can cause the oscillating mechanism to become misaligned.

Tom, many thanks for that advice.  I read in some book--maybe it was an instruction manual--that router bits should be tightened very hard.  Two follow-up questions, if I may:

(1) why do the router bits sometimes loosen in my OF1000, even thought I've tightened them to the point I'm afraid I'll strip the collet?  (I don't use lubricant in the collet or on the bit)

(2) can over-tightening the collet increase the runout of the bit?

Apologies if my questions are thread drift, but I figured this thread has already drifted a bit 

And thanks, Rick, for having the courage to ask your potentially humiliating question, because it's allowed me to ask a couple of my own.
Regards,

John

 

[tbellemare]

John:

If you look at router collet anantomy, it is not likely the collet itself but possibly resin build up or other detritis that is causing a collet not to grip securely. After all, they work when they are new...

The advice that John gave, above, about keeping things clean is probably the most important. If the collet is dirty or the bit is dirty, or even the router spindle is dirty, you can be "artificially tightenting" the collet fingers to the bit shaft. The tightening motion that should be transfered to the fingers against the bit can be used to compress something else that is in the way.

The inside of the spindle is a taper to pinch the fingers of the collet. The outside of the spindle is a thread used to drive the fingers of the collet into the inside spindle taper.

The fingers of the collet have to "come together" as they are driven into the taper mentioned above.

'Bottom line...

There are a few reasons why the collet might not grab the bit securely. If the system is clean, it doesn't take a lot of cranking on the collet to hold the bit (or release it).

Tom

 

[woodshopdemos]

do not leave bit in the collet it isnt good for the bit or the collet. If the bit is carbide tip, you should clean with bit and blade cleaner right then and there. Store router without bit.

Just wondering John, why is it bad to leave it in?

Alex,
  The collet is made up of steel fingers that grab the bit shank. When you tighten the collet, you remove the spring aspect of the collet. So remove the bit when not in use. As to how often...ie nightly, a week or what? I dont know. I do know what I do, I remove bits at the end of the day including the router table routers. That lets the collet flex and it is good time for me to clean bits. When you do that daily, there isnt much to clean which makes the task very quick and easy.

 

[score0matic]

I do not leave bit in the collet it isnt good for the bit or the collet.

John

do you have any documentation for this statement?    I know many pro's who dedicate routers to specific bits.  The only time they get taken out is to change them when they dull.

Craig

EDIT I posted this when I read his post only to find out others have asked the same. 

Follow up?

John isn't it the compression acting against the collet as the lock nut is tightened  that grips the shaft rather than the "spring aspect" of the collet's fingers? 

Thanks again

 

[jonny round boy]

John isn't it the compression acting against the collet as the lock nut is tightened  that grips the shaft rather than the "spring aspect" of the collet's fingers? 

It is, but the "spring aspect" of the fingers is what allows them to release the bit when the collet nut is undone.

 

[greg mann]

Over the years I have found John Lucas' observations to be right on the money but I think I need to disagree on this one (at least a little). There is so little movement in the collet as it is tightened that the spring tension is not affected at all. This can only happen if the collet is deformed beyond the yield point of the steel. That is not possible to do with a bit in place. As far as slipping is concerned: Ceanliness, cleanliness, and cleanliness are the three most important factors.

I do agree that it is not a bad thing to remove bits regularly when not in use. After all, when the bit is in and torqued the bit and collet are exerting outward pressure on the spindle walls. This could theoretically cause accumulated fatigue but not as much as actually using the router to cut wood will.

In metal machining we use collets all the time that are exposed to far more tightening pressures and far tougher usage conditions than router collets ever get. We often leave tools mounted in collets for years. Sometimes, when we take them apart, they are almost rusted in place since we do feed coolant through the spindle and tool. The slots are often totally filled with graphite dust that falls out of suspension when machining cast iron. This is a very hostile environment and collets take a beating. The inside of the toolholder, which would correspond to the inside of a router spindle can also be compromised from corrosion and grit. Accuracy is often compromised but, in spite of this, slippage is hardly ever an issue if everything is cleaned well prior to reassembly.

Lastly, it certainly is possible to overtighten a collet. If you cannot comfortably tighten a collet with the wrench provided and you are experiencing slip, then there is something wrong. Check cleanliness, length of engagement between shank and collet, routing technique, or an undersized shank. Taken to extreme you can tighten a collet so that it will generate enough pressure crack out the wall of the splindle. Haven't ever done it myself  but I have seen ham-fisted guys do it to toolholders that hold 1 1/2" shanks.

 

[Brice Burrell]

The only this I'd add after Greg's well written post is never tighten the collet without a bit in, this can deform the collet, ruining it.

As always Greg, great info.

 

[AlexThePalex]

John Lucas, thanks for your explanation. But just like Greg, I am not so worried about storing it with a bit in it. I got my router a good 10 years now and I've always stored it with a bit in it. I haven't noticed any negative effect yet, for both the bits and the collet. As for the spring effect, there's hardly any. The tolerance is less than a millimeter, and that's too small to have any deformation effects on the metal.

 

[John Stevens]

Thanks, Tom; thanks, Greg.  My collets and bits are always clean of dust and wood residue, but I've noticed some light rusting in the collets, about 10mm up at the end closest to the motor.  I wouldn't think that part would account for much of the clamping force, but I guess it'll be worth a try to clean that off and see if it makes a difference.  I would really like to get my OF1000 drilling precise 5mm and 1/4" holes.  The LR32 setup isn't much good if the holes are too big.

Regards,

John