Where does the assembly rate come from?

Measure a full build or time study on the same gearbox family, then divide gearboxes by the hours they took. A rate from a different size or a single best build will undershoot on a repeat order.

Why is alignment treated as a percentage?

Alignment and backlash checks scale roughly with the time the build itself takes: more gearboxes means more shafts to align and more backlash checks. A percentage of base hours follows that relationship better than a fixed adder.

Does the target include test and paint?

No. The target covers assembly, alignment and check hours only. Add test stand, paint and packing hours separately, or raise the target to absorb them.

What lowers gearbox assembly hours most?

The build rate, because every other figure divides from it. A 10% faster rate saves about 10% of both base and allowance hours, while trimming the alignment allowance by 10% saves far less of the total.

Bearings, Gears & Power Transmission calculator

Gearbox Assembly Labor Calculator

Estimate how long a gearbox build takes at your demonstrated assembly rate, then add the allowance for alignment and checks. The page compares the result with the hours you have.

What this calculator does

Assembly hours for a gearbox build, with the alignment and check allowance added and the total compared against your target.

Formula used

Base gearbox assembly hours = gearboxes to assemble ÷ verified assembly rate
Required gearbox assembly hours = base hours × (1 + alignment and check allowance ÷ 100)
Alignment and check hours = required gearbox assembly hours − base gearbox assembly hours
Hours over target = required gearbox assembly hours − target assembly hours

Inputs explained

Gearboxes to Assemble: Gearboxes released to assembly for this build.
Verified Assembly Rate: Sustained build rate proven on this gearbox family.
Alignment and Check Allowance: Allowance from a time study for alignment and backlash checks.
Target Assembly Hours: Hours the build plan allows for this order.

How to use the result

Best suited to staffing a reducer build cell, quoting assembly labor on a gearbox order, checking a repeat order against available hours.
Build hours only: kitting, cleaning, testing and paint are separate operations. Backlash checks assume the housing and bores are already to print.

Current U.S. benchmarks

The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

Where does the assembly rate come from? Measure a full build or time study on the same gearbox family, then divide gearboxes by the hours they took. A rate from a different size or a single best build will undershoot on a repeat order.
Why is alignment treated as a percentage? Alignment and backlash checks scale roughly with the time the build itself takes: more gearboxes means more shafts to align and more backlash checks. A percentage of base hours follows that relationship better than a fixed adder.
Does the target include test and paint? No. The target covers assembly, alignment and check hours only. Add test stand, paint and packing hours separately, or raise the target to absorb them.
What lowers gearbox assembly hours most? The build rate, because every other figure divides from it. A 10% faster rate saves about 10% of both base and allowance hours, while trimming the alignment allowance by 10% saves far less of the total.

Related guides

Last reviewed 2026-10-01.