What the??

[ED65]

Clarkson Milling Cutter.

Is that equivalent to an end mill Chas?

 

[CHJ]

Clarkson Milling Cutter.

Is that equivalent to an end mill Chas?

'Clarkson' is a brand and design, and is often used by oldies like me to refer to endmills made to fit threaded holders. Much like 'Biro' is still used to refer to ballpoint pens.

'Clarkson' style tool holders use the threaded shank and locking nut to hold the cutter in place and prevent it slipping or being pulled out of its holder by the cutting forces.
Other holders use a flat 'Weldon Shank' to stop the cutter rotating in the holder.

'Plain shank' End Mills can slip in a collet or be pulled out of a collet much the same as you get with a Router cutter if the clamping and cutter loads are not matched.

The generic 'End Mill' is a style as oposed to Horizontal Milling Cutter.

Endmills can vary in flute form, Some only have side flutes to cut on the side of the shank with limited nose cutting capability, others are specifically designed to have cutting edges on the end to allow plunge cutting when forming a closed end slot.

 

[Bedrock]

I have used them a lot for starting accurate metal drilling, but the smallest, I think "0"s and "1"s, are fragile. They are HSS I think, and I re-use the broken 0s reground as cutters/pins in cutting and mortice gauges.
When unbroken, I can find them useful when trying to centre spot through a larger hole, if I've forgotten to do it properly the first time.

 

[DTR]

others are specifically designed to have cutting edges on the end to allow plunge cutting when forming a closed end slot.

I've always known these as Slot Drills.