Thread: whats the difference?? 12.7 or 6.35

Hi Ford Fairlane

Talking straight cutters the finer cutters will often have the
smaller shaft, larger cutters the larger, this can determine their
workload ability, for instance a 15mm straight bit on a 1/4 inch
shank wont take as big a bite as a 1/2 inch shank, ie they can
break and make a hell of a mess if you try. So there's the stress
factor.
If you're using router guide bushes ( for dovetail jigs, template cutting etc) the guide bush size will determine bit shank size.

For me it's a matter of preference, sometimes cost, other times if i can be
bothered fighting with that sticky 1/4 inch reducer , I do try wherever
possible to buy solid carbide cutters in the 1/4 inch range (as opposed
to carbide tipped) just because of a few past experiences with cheaper
cutters) but once again, it's price and preference.

cheers
col.

Basically

For example a 3mm straight cutter would be next to pointless buying with a 1/2" shank just as buying a 3/4" cutter with a 1/4" shank.

I have a range of both 1/4" and 1/2" shanks.

Remember that the bigger the circumference on the shaft, the better grip so for larger bits where the torque is much higher (eg a slotter), I wouldn't contemplate getting one with a 1/4" shaft.

I also think that a heavy shank can help dissipate heat.

eg. I wouldn't have thought that it'd make any difference whether a 1/4" fluted bit had a 1/4" shank or a 1/2" shank.

But it does... a while back I was using 1/4" flutes for doing some trenching for drawer bottoms. I went through a couple 1/4" shanks quickly, but the 1/2" shank easily finished off more than the last half of the job. (One of the 1/4"ers was only blunted, but the other bent slightly out of true.)

They were all from the same mfr. (cheap! cheap! ) and I was feeding the same type of boards at the same rate.

Go figure!

thanks for the replies guys and what you say makes lots of sense. I was just confused when i see for sale the same cutting size bits in both shank sizes.

Thanks again!!

Some routers only take 1/4" bits but if you have a 1/2" router, you have the option.