End Mill Deflection Calculator

Inputs

View results
Free length from the holder face to the cutting edge.
in
Length of the stickout occupied by flutes. Values above stickout are clipped to the stickout length.
in
Nominal cutter or shank diameter used for the round-section stiffness basis.
in
Side load at the cutting edge. Use measured force or estimate from cutting power, engagement and material.
lbf
HSS/steel shanks are about 200 GPa. Carbide is commonly much stiffer; enter the tool material value.
Mpsi
Effective fluted-section area moment as a fraction of a same-diameter solid round bar. Use 1.0 for a solid shank approximation.
I/I_solid
Tip movement limit for tolerance or finish. Use tighter values for small cutters and finishing.
in
Elastic bending stress screen for the cutter material. Final tool failure depends on geometry, carbide grade, defects and dynamic load.
ksi

Results

Default result
Edit inputs
Tip deflection(delta)
0.0002787in
Pass

delta = F/(3*E*I_solid) * [L^3 + Lf^3*(1/phi_I - 1)].

Also computed

Deflection utilization(delta / delta_allow)Pass0.557x

Bending stress(sigma)Pass2.445ksi

Governing stress location: holder support.

Stress utilization(sigma / sigma_allow)0.0337x

Overhang ratio(L/d)Pass3L/D

Effective fluted length(Lf)0.75in

Fluted length clipped to stickout if needed.

Flute deflection penalty(delta / delta_solid)1.1x

Multiplier versus a same-diameter solid round shank over the full stickout.

End mill deflection previewEnd-mill stickout stiffnessRound cantilever with fluted-section inertia factor.tip deflection0.0071 mmdeflection limit56%stress limit3%
Method notes 3 notes
  • End mill stickout is modelled as a round cantilever with radial force at the cutting edge.
  • The fluted part of the stickout uses I_fluted = phi_I * I_solid. The solid round basis is I_solid = pi*d^4/64.
  • This is a static stiffness and elastic stress screen. It does not predict chatter, stability lobes, holder pullout, flute stress concentration, runout, chip-load variation, tool wear or toolmaker limits.

Powered by MachineCalcs ↗