As I can’t sharpen my existing cutters I will have to buy new - but have no idea what these are likely to be called. I have 3 collets - and the cutters all have threads on the to.
What do I need to be looking for please?
Odd cutter pictured it has straight flutes which may be some specialist type for wood or plastic butchery?
That could be an advantage as may be much easier to sharpen by hand.
Called screwed shank cutters, and I think that is a Clarkson Autolock type of collet. I've not used the collets but I abuse many of the cheap screw shank cutters In a normal er chuck.
You'll need to measure the diameter, and make sure to get the correct diameter.
Threaded cutters are getting harder to get, as very few places still use them. If you can adapt the mill to something like ER collets, then it'll open up far more options for cutters.
99% of threaded shank cutters use the Clarkson thread (that is to say, you would be very unlucky to buy a random threaded shank cutter and it not fit).
The one pictured is imperial. The 'ears' of a metric Clarkson collet have a small v-groove cut into them to show it is metric.
It is the imperial diameter that makes them more difficult to find (Chronos have slot drills, end mills and ball nose cutters in imperial). Threaded shank metric HSS cutters are still plentiful.