Simple safety flycutter

[Mook]

I've never been comfortable with the tool protruding from a flycutter body, it becomes invisible when spinning fast. If you do use flycutters try to use the appropriate size to minimise or eliminate any tool protrusion from the body. This 2lb tool has a cutting radius of 45mm and is designed to use the 100 degree corners not often used on CNMG shape inserts. The 75 degree leading edge gives a smooth engagement with the part, minimising impact and the inserts are virtually free. With the tool slightly protruding past the body the maximum depth of cut is 11mm.


Starting from scratch the design ignored the traditional tilted tool which is simply not required unless square HSS toolbits are used. This is because insert tools have the cutting point protruding from the tool body, naturally having its own clearance. This simplifies the design considerably and is easily scaleable.
The traditional downsides of flycutters are:
Safety from invisible spinning protruding tools.
Tip impact on the workpiece and spindle.
Balance and rigidity.
Painfully slow & uneconomic.


Taking care with the design to minimise the inherent shortcomings with flycutting I compared it with a relatively inexpensive button tool to see the results. As expected, the button tool far outperformed the flycutter for metal removal rates and the finish was surprisingly far brighter.

Watch a button insert really earning its money double tandem cutting while also chamfering on the inside of the inserts here.