These are deigned to to locate on the flat. Centre height is at the cutting edge of the insert.

Jim

Holding by the flats gives a reasonable rake but you can get square holders that allow angle tweaking and may be more convenient. These from Arc Euro Trade.

Dave

You don't need to hold them in a round holder just let the flat bottom sit in a standard toolholder or post and the grub screws onto the top surface. As said the angle gives the edge of the tool clearance and usually gets less as the dia of the bar and therefore minimum hole size goes up.

Edited By JasonB on 28/03/2020 13:02:10

I am guessing that Jason has put these bars into holders to show the negative angle and would pack the front of that small one if intended for use so that the grub screw has more tool to tighten onto.

No, I had been using it for something that needed it set at an angle to the toolholder lengthways for clearance just before taking the photo. usually just set directly below the screws. I've got 5 or 6 holders all with their own bars so just picked them up for the photo.

J

Edited By JasonB on 28/03/2020 13:18:55

Ahh ok.