Advantage to 1/2" Shank Router Bits?

[Jim Dwight]

I don't remember any ruined projects from it but my Bosch Colt has had a bit slip some in it's collet. That's why I don't think it is all in the quality of the collet, I think some of the blame is on the shank area being too small. But I still use my Colt and like it. I just have to remember to only take light cuts with it. The motor is stronger than the collet can grip.

On the other side, even my big 3.5 hp Porter Cable router motor in my router table does not slip bits with half inch shanks.

For any cut where you are removing a serious amount of wood, my opinion is you want a half inch shank. For a 1/8 roundover or a small chamfer or something it doesn't matter. But for nearly any dado cut, using a 1/4 inch shank bit is asking for a damaged project.

[Dennis McDonaugh]

The reason for the question — I was standing there looking at a bunch of worn out 1/4” straight router bits with 1/2” shanks and wondered if I could save a couple of dollars by buying 1/4” to replace them.

I don’t know I’ve ever experienced a bit slipping. Does it stop spinning for an instant?

[Mike Henderson]

The reason for the question — I was standing there looking at a bunch of worn out 1/4” straight router bits with 1/2” shanks and wondered if I could save a couple of dollars by buying 1/4” to replace them.

I don’t know I’ve ever experienced a bit slipping. Does it stop spinning for an instant?

What most people refer to is that the bit moves up or down in the collet when it "slips" and what you're using the router on gets messed up.

Mike

[Wes Billups]

I'm one of those that started with exclusively 1/4" shank router bits because my Craftsman router only took that size. Over the years I got a larger router that accepted 1/2" bits and began collecting some of the larger sizes.

It wasn't until I was trying to dovetail baltic birch plywood with a dovetailing jig that I learned the advantage of 1/2" shank. I just could not route the tails without tear out, I even bought a new 1/4" shaft dovetail bit thinking my original was too dull. I then tried a 1/2" dovetail bit and the chip out disappeared. Only thing I can figure is the 1/4" shank allowed too much chatter causing the chip out. Ever since then I've used a 1/2" shank for anything that'll allow it and only use the 1/4" or 8mm when required.

[Mel Fulks]

The slipping is most often caused by not having the bottom of bit 1/8th off the bottom of the collet.

[Andrew Seemann]

I tend to prefer 1/2" shank bits solely so I don't need to swap out the collet on my routers. I know that is a lame excuse, but the extra 5 minutes to change a bit really does irritate me. I do have a fair number of 1/4" shank bits for my trim router which I use, and some additional ones I inherited. In general, I rarely buy new 1/4" shank bits unless specifically for my trim router.

On a side note, I have always wondered why bottoming out a router bit would cause it to slide out. Is it from heat? That seems like it would maybe total to a couple thousandths of an inch, assuming expansion of the bit at one millionth of an inch per degree per inch, and no expansion of the collet.

[Ed Aumiller]

Slipping ....

When you tighten the collet on most routers, the bit will move slightly further into the collet... if it is bottomed out before tightening, it cannot move and will not be as tight as it should. Leave a small gap to allow it to move...