Couple of Router Questions Regarding How Much of the Shank Needs to be in the Collet

[George Bokros]

I am making the jig to make beaded face frames on my router table. I just checked and using 3/4" material for the base and the sliding table my bit will not be high enough unless I insert it only about 7/16" of the shank into the collet, is that deep enough to hold it securing and safely?

Are collet extensions safe to use? With one of those I could get it deeper into the collet and it should be able to have the height (depth of cut) needed. Maybe a collet extension would be too high, I don't know since I do not have one. Most extend the cut 2 1/2 inches.

Thanks


George

[Grant Wilkinson]

A lot of this will depend on how much wood you are taking off with each cut, your rate of feed, and the wood itself. I'd be OK with 7/16" in the collet, taking it easy. I'm assuming that your bits are 1/2" shank.

[Duane Meadows]

No, it is not! About 1" is best... less than half of that is a pretty scary thought!

[George Bokros]

Yes the bits are 1/2" shank. Cutting the notches when doing beaded face frames removes quite a bit of wood at one time. You are cutting at least 1 1/2" wide approx 1/2" to 3/4" deep through stock 3/4" thick.

George

[Jim Rimmer]

QUOTE=George Bokros;2164783]Yes the bits are 1/2" shank. Cutting the notches when doing beaded face frames removes quite a bit of wood at one time. You are cutting at least 1 1/2" wide approx 1/2" to 3/4" deep through stock 3/4" thick.

George[/QUOTE]
Given that size and depth of cut, 7/16 is not enough.

[Myk Rian]

More than half the shank, minimum.
Just as long as you don't bottom it out you'll be ok.
If you put the shank till it bottoms out, tightening the collet will try to force it deeper, and it will not grip it.
I've seen too many horror stories about it.

Collet extensions are ok, but, slow the speed down. Also realize that they can introduce more wobble to the bit.

[Jamie Buxton]

Pull the collet out of the router. Insert the bit. Look at the rear of the collet. You'll see it contacts the bit shaft. You want the entire gripping length of the collet in contact with the bit. On my big router, the collet gripping length is about an inch. On my small one, the gripping length is more like 5/8".

[Mike Wilkins]

My method is to insert the bit as far as it will go, and then back it out approx. 1/8". The more meat contact the collet, the more contact area you have for gripping. As for the extensions you sometimes see in the catalogs-I considered getting one but the salesman and the instructions both talked me out of it. Instructions dictated inserting and re-inserting the bit until you had minimal run-out. That was enough of a deal-breaker for me to leave it in the store. Something that introduces run-out into a spinning cutter just did not sound right to me. Or safe.

[Ed Aumiller]

Bit extensions also introduce FLEX... On something like you are using, you want NO flexing... keep the cutter as close as possible to the collet...
Also, take several small cuts and don't try to do it all in one pass.. Much safer that way..

[glenn bradley]

Seems there are opinions on this but, the better cutter manufacturers have guidelines on their websites. I'll throw in with the 1" crowd since that is what I see recommended most often (and it is also the rule I follow). IMHO, if you need more extension, buy an appropriate bit (at best) or use an extension (only when you have to). I have gotten extra long bits from Whiteside at minimal additional cost. When you have 2" of bit hanging out in space it is comforting to have an inch or so in the pipe.

[George Bokros]

I have re-thought the design of my jig for the beaded face frames and gained at least an extra 1" of shank in the collet.

Thank you everyone for your thoughts and suggestions. I did not think 7/16" was adequate in the collet but sometimes I find my self being overly cautious safety wise. As far as a collet extension, I have always thought they were not a good idea. I want to make beaded face frames for an upcoming project and was beginning to build the router table jig to do so.

George

[glenn bradley]

I have re-thought the design of my jig for the beaded face frames and gained at least an extra 1" of shank in the collet.

Excellent. Good discussion.