I've never bothered to fit a keyway into my gear cutters when I have used them, seem to work fine.

You probably want to start buying from a proper tool supplier……………

All my involute gear cutters have keyways, and I always use keys, even though you might get away without it for larger DP, ie, smaller teeth. But then again I drive my cutters fairly hard on rigid machines. Of course Brian is correct, there is no point in taking multiple cuts with involute cutters, it just wears them out and wastes time.

Andrew

My one inch horizontal milling shaft does not have a key slot. Presumably this was deemed good enough for the full power of 1HP of the original motor.

Neither do my 250mm circular saw nor my angle grinder. Agreed, it may depend on the contact area and torque, but I doubt the average hobbyist really needs a key, in most situations, for gear cutting.

Select your tools carefully. Most rolson, silverline, black spur (and others) tools are avoided by me, unless they are for a one-off easy duty task. 'Buy cheap, buy twice' is a good maxim to follow.

I think the biggest risk to tooling caused by operating without a driving keyway and relying on the grip from spacer collars alone is to slender cutters, like slitting saws.

If the saw stalls in the cut, but feed continues to be applied, even by hand, the result may well be enough to shatter the cutter from buckling, something it cannot tolerate.

Brian

I don't use keys for any of my 1" and 1.25" bore cutters and I've never had a problem but then I don't expect industrial production rates. However, I could forsee a problem if the cutter was fitted in a dirty state and then tightened itself altering the position when gear cutting. Colin

It might just be an economy measure to make the arbors cheaper?

Andrew,

It may not be the original arbor, but is likely. Doubt it was a cheap economy measure, if original, as it is a Centec.