Insert Tip radius?

I’m just wondering what tip radius most of you find the most useful for carbide inserts? I’ve just bought some .4’s so I can get a reasonably tight shoulder and the finish was good. I’m just wondering if I should get some .8 as well? If I need a really tight shoulder I use HSS in a tangential tool but I like using inserts for aluminium alloy.

I mostly use 0.2 but my work may well be smaller than yours. the 0.8 ones tend to come out if I want a small internal fillet or am working on a large part.

As standard I use 0.4mm. The 0.2mm is a bit delicate so I use it only when I need a smaller fillet. The 0.8mm inserts get used for roughing.

Andrew

I tend to use the 02 insert for most of the work I do, usually small aluminium/brass/Plastic parts that don't need any larger fillet at change of diameters.

When cutting stainless or EN8/16/24 I change insert to a .4mm tip rad.

I only use .8mm rad when not cutting to a shoulder or facing to centre, the length of cut if using a roughing pass up to a shoulder is too great for the speeds and feeds I use on a small cnc lathe.

Emgee

I find the ccgt tips used for alu give a better finish with a larger radius .4 or above. The .2 leave a fine spiralling.

I mostly use .4mm radius because it is what is easiest to find where I live. I use 0.8mm when not turning to a shoulder.

Thor

I have some 0.1, they have only been or use for drag engraving, but having a selection from 0.2 to 0.8 comes in handy.

Thanks for your thoughts folks, most helpful.