Robotic End-of-Arm Tooling worked example

Custom Bracket Machining Cost at 58% billable spindle-cutting share: a worked example

This worked example runs the custom bracket machining cost numbers for a tougher week than the baseline: 58% billable spindle-cutting share instead of the typical 80%. Estimate the cost to machine a custom EOAT mounting bracket or adapter plate from CNC hours, shop rate, and material.

The inputs for this scenario

  • Bracket machining hours: 9 hr (held at the documented default)
  • Machine-plus-operator shop rate: 95 $ / hr (held at the documented default)
  • Billable spindle-cutting share: 58 % (the input this scenario stresses; the baseline uses 80)
  • Stock, fixturing, and programming cost: 640 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Bracket machining cost = bracket machining hours x machine-plus-operator rate x billable cut-time share + stock, fixturing, and programming.
  • Total custom bracket machining cost works out to 1,136 $ at these inputs, and this is the headline figure for the scenario.
  • Custom bracket machining cost per unit works out to 126 $ / piece at these inputs.
  • Variable custom bracket machining cost works out to 496 $ at these inputs.
  • Fixed custom bracket machining cost adder works out to 640 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where billable spindle-cutting share sits at 80% and the headline result is 1,324 $, this scenario comes in 14.21% below the baseline at 1,136 $.
  • Use it when quoting or costing a one-off or low-volume machined EOAT bracket, adapter plate or sensor mount. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Total custom bracket machining cost: 1,136 $ (headline result)
  • Custom bracket machining cost per unit: 126 $ / piece
  • Variable custom bracket machining cost: 496 $
  • Fixed custom bracket machining cost adder: 640 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Custom Bracket Machining Cost calculator, set billable spindle-cutting share to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.