This bit is for round cutting and is sometimes referred to as a "ball end mill."  

The shank diameter is 16 mm and the diameter of the cutting edges is 14 mm, yielding an end radius of 7 mm.  The total length is 70 mm, and the material is SK53, which is similar to 1095 carbon tool steel. 

One advantage of making your own tools is the freedom to make various sizes and styles, both standard and non-standard.

The rake angle is 0 degrees.

Forming a radius on cutter end.  

See Article Number 33 for information on the radius cutting tool.

Workholding using three-jaw chuck, Index Table and Tilting Angle Plate. 

See Article #23 for more on the Index Table and Article #30 for more on the Tilting Angle Plate.

Two flutes are cut.  The first pass machines the flute;  the second pass cuts some clearance.

After  clearance is cut, file the edges precisely while watching with a  10X magnifier.

Hardening and tempering using a torch. 

After tempering, grind the cutting edges and use emery cloth to remove any discoloration  from the shaft.

Successful  test cutting of cast iron.

This was the first radius cutter I made and I was very pleased with its performance.