S721 → TS21 replacement

Replacement referenceDirectional lookup

Existing / searched modelBoston GearS721Open source-model record →

Published target modelToledo GearTS21Open target specs →

What the source establishesFunctional interchange

Toledo Gear publishes TS21 at 2.06 in center distance for shaft input / shaft output and lists the competitor models in the same TG-90 interchange row. Toledo describes TG-90 reducers as designed to be functionally interchangeable while requiring current rating and dimensional verification.

Evidence meaning

The manufacturer describes the target family as functionally interchangeable with the listed competitor model or configuration.

Boston Gear S721 and Toledo Gear TS21 are tied by the published source at Match installed ratio · 2.06 in center distance.

Evidence boundary

The source still requires ratings, dimensions, ratio, fit, and application conditions to be checked before ordering.

Published target specifications3 model-level fields

Toledo GearTS21TG-90

Full model record →

Center distance: 2.06 inSource ↗
Configuration: Shaft input / shaft outputSource ↗
Interchange basis: Toledo TG-90 Interchange GuideSource ↗

Other models in the same published row9

Replacement verification checklistBefore purchase

RatioConfirm nominal and actual ratio against required output speed.

Shaft / boreMeasure the driven shaft and verify bushing or bore configuration.

InputCheck high-speed shaft, motor frame, sheave and input interface.

MountingCompare center height, footprint, torque-arm geometry and housing clearances.

AccessoriesDo not assume existing backstops, motor mounts, belt guards or screw-conveyor hardware transfer.

DutyRecheck torque, service factor, shock, starts per hour, temperature and lubrication.

Boston Gear S721 replacement