MIM Stainless Steel Bevel Gear | Precision Smart Lock Transmission Gear

What Is a Smart Lock Bevel Gear?

The bevel gear is the mechanical translator inside a smart lock: it converts the motor's horizontal rotation into the vertical rotation that drives the lock cylinder or deadbolt mechanism. When the fingerprint sensor authenticates, a small DC motor spins — and a pair of bevel gears redirects that motion 90° to throw the bolt.

It is a tiny gear — typically 8–15 mm in diameter, module 0.3–0.6 — that carries a disproportionate amount of the smart lock's mechanical responsibility. If the gear teeth wear, the lock develops slop and noise. If a tooth breaks, the lock fails closed — or worse, fails open. And if the gear's bore tolerance is loose, the entire drive train sounds like a coffee grinder.

At Precision-mim, we MIM-manufacture bevel gears in stainless steel — capturing the full tooth geometry, bore, and hub features in one shot, with the material strength to handle thousands of lock/unlock cycles without degradation.

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MIM Stainless Steel Bevel Gear | Precision Smart Lock Transmission Gear

Why MIM for Small Bevel Gears?

Small-module bevel gears are a nightmare to machine conventionally. The tooth profile is three-dimensional — it changes shape from the outer diameter to the inner diameter — which means a standard gear hobbing machine cannot cut it (hobbing produces spur and helical teeth, not bevel teeth). True bevel gear cutting requires a specialized Gleason or Klingelnberg generator — expensive machines that are rare in job shops and impractical for sub-module-1 gears.

MIM sidesteps the entire machining problem:

Full 3D tooth profile molded in— straight, spiral, or Zerol bevel tooth forms, no cutting required
Integrated hub and bore— keyway, set-screw flat, D-bore, or spline molded concentrically with the gear teeth
Lightening pockets— weight reduction features molded into the gear body
Batch consistency— every gear in the batch has identical tooth geometry; no tool wear variance

Cost comparison for a module 0.5, 15-tooth stainless steel bevel gear:

CNC machined (5-axis + wire EDM): $8–15/part at 1,000 pcs
MIM: $1.50–3.00/part at 10,000+ pcs — and the tooth finish is better

Material Selection

Material	Hardness	Best For
SUS304	HRB 70–85	General smart lock gearing, low-noise operation
17-4PH H900	HRC 40–45	High-torque deadbolt drives, commercial locks
316L	HRB 75–85	Outdoor/coastal locks, maximum corrosion resistance
440C	HRC 56–60	Maximum wear life, high-cycle commercial applications

Gear Specifications We Mold

Parameter	Range
Module	0.3 – 1.25
Number of teeth	10 – 60
Pitch diameter	5 – 50 mm
Tooth form	Straight bevel, spiral bevel, Zerol
Pressure angle	20° standard, custom on request
Gear ratio (mating pair)	1:1 to 6:1
Bore type	Plain, keyed, D-bore, hex, splined
AGMA quality class	Q8–Q10 as-molded, Q10–Q12 after burnishing

Design Features

Molded tooth profile— full involute or octoid tooth geometry, no secondary cutting
Concentric bore— as-molded TIR <0.03 mm to tooth pitch circle
Integrated shaft— gear + pinion shaft molded as one piece
Anti-backlash split gear— spring-loaded split gear design for zero-backlash smart lock drives
Lubrication groove— molded-in grease retention channels on tooth flanks

Quality Assurance

Tooth profile inspection — gear roll tester or optical profilometer
Dual-flank roll test — center distance variation per AGMA standards
Hardness — batch verification
Bore concentricity — dial indicator, <0.03 mm TIR

Smooth, quiet, reliable — the smart lock experience starts with the gear train. Our ISO-certified MIM process delivers gears that mesh right the first time. See Quality Assurance for documentation.

Need a bevel gear set for your smart lock design? Send your gear specs — module, ratio, torque requirements — and we'll provide a DFM review and quote.