The triangular insert has 3 cutting edges per side. It has less corners than the square type, but is effective in machining right angles and for copy machining (copying). This insert has a cutting edge point angle of 60° and therefore it has less cutting edge strength when compared to a square insert.

These types of inserts are often used for copy machining. The insert itself has less cutting edge strength when compared with other inserts geometries. However, it is essential for copy machining. The use of either 55° or 35° depends on the geometry of the workpiece being machined.

This insert can be used for external machining and facing, and such is often used on CNC lathes. It is the most commonly used insert.

The round insert offers the strongest cutting edge. Additionally, due to the large radius it provides the best surface finish. However there are a few disadvantages.

The cutting edge angle is 80° and therefore offers high cutting edge strength. However due to the short cutting edge length the depth of cut is limited.

These types of inserts are often used for copy machining. The insert itself has less cutting edge strength when compared with other inserts geometries. However, it is essential for copy machining. The use of either 55° or 35° depends on the geometry of the workpiece being machined.

Have a small project where I need to mill a flat on some steel bar stock. I've seen the Carbide 3d Material Monday youtube video where they mill some mild and 303 stainless on a shapeoko 3. They chose a 4 flute 3/32 AlTin coated corner radius end mill.

The insert geometry, tolerance, dimesions, and terminology are all based on the ISO standards. Other countries such as America (ANSI) and Japan (JIS, CIS) have their own standards but they are all based on the ISO standards.

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The square insert has 4 cutting edges per side. If the insert is negative then it is possible to use a total of 8 corners. Thus making this style of insert very economical. The insert has a cutting edge angle of 90° so it has high cutting edge strength. However, the square insert needs a side cutting edge angle to machine and and such can not be used for machining a right angle.

I'm looking at two 1/8" AlTin coated, corner radius end mills. Only difference is that one is 2 flute and other is 4. For my shapeoko which has a makita router, would the 2 flute end mill be better? The low end of the RPM range on the router is fairly high. My thinking is that I might have issues feeding it fast enough to keep a decent chip load on a 4 flute end mill. The 2 flute would basically make up for my high spindle rpm. I know that people love single flute mills for aluminum but I'm wondering if there's anything special about steel where the "less flutes = better on a hobby cnc" wouldn't apply.

"Inserts" or indexable inserts are used as the cutting edges for cutting tools such as tool holders for turning and face milling cutting for milling.

For example, due to the long cutting edge the chips developed are relatively wide and such difficult to break. Also due to the large contact area and the long cutting edge length, the load on the insert increases. This can result in vibrations when machining small or thin walled objects.

Round inserts are best suited for machining that requires high cutting edge strength, such as interrupted cuts, removing scale, and when machining cast iron as the chips do not elongate.