21T 0.5M Pinion Gear MG321T/0.5M 40Cr Steel for RC motor shafts by GPM  [MG321T/0.5M]

40Cr Steel Motor Gear 21T ( Module:0.5mm, Motor Tooth Diameter:3.175mm) - GPM MG321T/0.5M
Price:
AUD$11.00
Brand:
GPM
Model:
MG321T/0.5M
GTIN:
4894538411454
Condition:
Brand New
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Small pinion with hardened steel construction

This GPM MG321T/0.5M motor gear is a low-profile pinion built for scale RC drivetrains that call for a 21-tooth, 0.5mm module pinion. The part is produced from 40Cr steel and finished in hardened black to improve resistance to wear over standard replacement gears.

Provided dimensions let you verify fitment: 21 teeth, module 0.5mm, and a motor tooth diameter of 3.175mm with a round motor bore. The pinion clamps onto the motor shaft via two 3x3 set screws; check your shaft diameter and spacing prior to installation to ensure correct mesh geometry.

As a replacement or tuning component this pinion offers predictable mesh behavior when matched to the correct module and tooth count. The hardened steel helps delay wear under normal RC loading, and the round bore with dual set screws simplifies alignment on common motor shafts. Always recheck mesh clearance after installation.

How does tooth module affect mesh?

Module defines tooth size and pitch; using the 0.5mm module pinion with a matching spur keeps contact correct and predictable, preventing uneven wear and noisy engagement.

Can I swap this onto any motor with a round shaft?

It fits motors with round shafts that accept set-screw pinions, but you must confirm shaft diameter and whether the motor has sufficient shaft length and clearance for two 3x3 set screws.

Should I check anything after installing?

After installation, verify mesh by spinning the drivetrain by hand, inspect for tight or loose spots, and make minor motor position adjustments until the engagement is smooth across the tooth face.

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