# Milling cutters

How to determine such a milling cutter in estlkam?

I would use this settings

I’m pretty sure that in most v11 applications the angle setting will be ignored and that it will be treated like a straight ballnose tool, i.e. it will overcut perimeters if set to the small diameter. 2.5D Carving expects a pointy bit and I’m pretty sure that the edge radius setting will be ignored, i.e. potentially major overcuts.

v12 added support for tapered ballnose tools and will warn you if it thinks a tool choice is unsuitable for the task at hand.

Although I think the question was how to define the cutter, it may very well be that the angle is not taken into account when calculating the cutter path. That would result in a groove that is too wide and seems easy to control.

I applied similar settings and that’s what happened (this is a test model)

In v11 the 2.5D Carving finishing allowance is a Z offset, but using it automatically adds a finishing pass so it cannot be used to …prevent over-the-line perimeter cuts when using blunt V-bits (like it can w/ parts, holes and r/l engraving)

In v12 there are both tapered ballnose (radiused tip V-bits) and flat tipped V-bit tool options, i.e. no Z offset required.

Getting accurate to-the-line perimeters with that radiused tip 60 degree V-bit in v11 would require setting Z zero at .40 above the material and adding .40 to the DOC. 60 degree radiused V-bits are easy because the distance between a radiused tip and a pointy tip is the same as the tip radius (whatever it may be). Flat tipped V-bits are generally easier because you can use an Isosceles Triangle Calculator. Related thread: Tool settings for flat tipped v-carve bit - #11 by dalrun (drawing, calculator example is down the page a bit).

Dave, of course you are right but I think the vast majority of machines used here are not stiff enough to prevent small bumps on the bottom. I myself have a professional machine made off cast iron, with 30mm ballscrews and still not yet stiff enough to make a mirror-like milling path with a flat milling cutter.

In V11 there is also a tip offset that appears to cover the case where the tip is higher (shorter) than the intersection of the extension of the tapered sides. Regardless of flat or curved, I would hope this would avoid the need for external hacks for setting Z offsets, but I haven’t used it so I can’t say. But it looks like it would cover this case.

…Setting Z zero to Tip offset above the material and leaving Depth limit at Automatic also works (v11 Carving).