1/2" and 1/4" Shanks On Router Bits, What's The Difference?

[fjl]

I know it just means the shank on the bit is different size but is there an advantage of using one or the other size? My router can support both sizes.

[fixedpigs]

always go bigger...!

a half inch shank will reduce vibration significantly over a quarter inch...

[ScottS]

I buy only high-quality bits and can't say that I've noticed much difference between those with a 1/2-inch shank and those with a 1/4-inch shank. In theory, 1/2-inch shank bits have more mass and less vibration which leads to smoother cuts and less chance of burning the wood.

[TOK]

Go with half inch if you're trying to decide. When you get into stuff like roundover bits, the larger sizes are only available in 1/2" shank.
I learned this the hard way, and I'm going to wind up buying a router with a 1/2" shank.

[fjl]

Cool, thanks for the info. I kind of figured the 1/2" would be better simply for more durability and strenght cause of its larger size. Didn't realize it would influence vibrations.

It's too bad I didn't know this back when I bought that set from Holbren as I ordered the set in 1/4" in shaft 

Oh well, at least I'll know to get the slot cutter bit in 1/2"

[ChadTower]

I would imagine it being hard to make a 1/4" plunge cut with a 1/2" bit.

[fixedpigs]

I would imagine it being hard to make a 1/4" plunge cut with a 1/2" bit.

why...?

just the shaft would be 1/2" chad...it would taper to 1/4" for the actual cutting surface...

[ChadTower]

It certainly looks as though some of the bits I'm looking at are not 1/4" diamater on the cutting end.  Pattern bits, perhaps, but not some of the others.

[scotthh]

The 401 kit has 1/2" shanks
The 402 kit has 1/4" shanks
Both kits have 7 bits with the exact same cutting profile.

Look at bit 1058 in the 401 kit: it has a 1/2" shank and a 1/4" straight cutting area
Look at bit 1013 in the 402 kit: it has a 1/4" shank and a 1/4" straight cutting area
These two bits will yield the exact same cut.

Look at bit 1067 in the 401 kit: it has a 1/2" shank and a 1/2" straight cutting area
Look at bit 1026 in the 402 kit: it has a 1/4" shank and a 1/2" straight cutting area
These two bits will yield the exact same cut.

Here's why I'd go with 1/2" shanks:
1) As TOK mentioned the largest bits only come with 1/2" shanks. This is because a 2" bit with a 1/4" shank would be much more susceptible to breaking than a 2" bit with a 1/2" shank.
2) You may never break a shaft or notice lower vibration, but it is even less likely with 1/2" bits.
3) They cost about the same.

If you have 1/4" bits, keep using them!