Exact circumference arithmetic
Cutting Surface Speed ↔ Spindle Speed
Convert between peripheral cutting surface speed and spindle rotational speed using the actual cutting diameter for the operation. Metric and inch formulas are evaluated directly in their stated units.
Kinematic conversion
These are circumference-times-revolutions unit identities, not ISO acceptance formulas. Sandvik Coromant metric milling formulas define Dcap as the cutting diameter at cutting depth ap and give both metric equations. The official inch milling formula sheet gives the corresponding factor 12.
Cutting surface speed is a kinematic quantity, not an intrinsic material property. A recommended value is an operating selection. Kennametal’s official guidance identifies work-material hardness/heat treatment/alloy, tool material/shape/condition, coolant and fixture stability as relevant inputs. The former generic HSS/carbide material table and presets did not identify these conditions and have been removed.
No machine-command guarantee: compare calculated n with tool-holder/tool maximum speed, spindle range, workholding/chuck limits, workpiece integrity, balance, machine torque/power and OEM restrictions. Never exceed the lowest applicable rated speed.
The procedures described on this page were developed and field-tested by the Vibromera team using the Balanset-1A, a portable dual-channel balancer and vibration analyzer for on-site rotor balancing.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
