Fastener Manufacturing & Thread Rolling worked example

Heat Treat Load at 66% furnace uptime during window: a worked example in fastener manufacturing & thread rolling

Here is what the math looks like when conditions slip. We hold every other input steady and drop furnace uptime during window to 66%, then walk the calculation through step by step. Estimate good fasteners available from a heat treat load after tray capacity, furnace cycles, uptime, and yield are applied.

The inputs for this scenario

  • Accepted fasteners per furnace load: 18,000 pieces or lb (held at the documented default)
  • Planned furnace loads: 6 loads (held at the documented default)
  • Furnace uptime during window: 66 % (the input this scenario stresses; the baseline uses 92)
  • Heat treat first-pass yield: 98 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Gross heat treat load = accepted fasteners per load × planned furnace loads.
  • Good output capacity works out to 69,854 units at these inputs, and this is the headline figure for the scenario.
  • Gross furnace load works out to 108,000 units at these inputs.
  • Uptime loss works out to 36,720 units at these inputs.
  • Heat treat yield loss works out to 1,426 units at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where furnace uptime during window sits at 92% and the headline result is 97,373 units, this scenario comes in 28.26% below the baseline at 69,854 units.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to furnace uptime during window, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It treats uptime and yield as flat averages, so it won't capture a single bad quench, a furnace recovery period after a cold start, or load-to-load hardness drift that scrap a specific basket.

Results at a glance

  • Good output capacity: 69,854 units (headline result)
  • Gross furnace load: 108,000 units
  • Uptime loss: 36,720 units
  • Heat treat yield loss: 1,426 units

Run it with your numbers

  • To rerun this with your own numbers, open the live Heat Treat Load calculator, set furnace uptime during window to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.