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Boston Gear HF721 replacement & specifications | Replacement Intelligence

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Boston Gear

HF721

current

Boston Gear P-8565-BG dimensional-interchange target for Hollow output shaft — NEMA C flange reducer (quill input) at 2.06 in center distance. Ratio is selected separately within the 700 Series range. Record source ↗

Source-backed record · Last reviewed Sep 21, 2026Compare this model →Verification methodology →

Specifications

Known configuration

5 fields

Center distance: 2.06 inSource ↗
Input / mounting style: NEMA C flange / quillSource ↗
Interchange basis: Boston Gear P-8565-BG dimensional interchange tableSource ↗
Output shaft style: HollowSource ↗
Single-reduction ratio range: 5–100 :1Source ↗

Cross-reference

Replacement candidates

No verified one-to-one replacement relationship yet.

Manufacturer transition notices are kept separate from exact compatibility so a group-level product transition is never presented as a drop-in replacement.

Interchange check

What must match before substitution

6 checks

Ratio / speedConfirm the replacement produces the required output speed at the actual input speed.

Torque / dutyVerify continuous and peak torque, service factor, shock loading, starts per hour, and thermal duty.

Output geometryMatch shaft or bore diameter, key/spline/bushing, output side, usable length, and allowable overhung/thrust loads.

MountingCheck foot pattern, flange pilot/bolt circle, center height, torque arm, and mounting position.

Input / motorConfirm motor frame, adapter, input shaft or quill, power, brake, encoder, voltage, and frequency.

Environment

HF721

Known configuration

Replacement candidates

No verified one-to-one replacement relationship yet.

What must match before substitution

Verified channels listing Boston Gear