HH-370 vs HH-31ZY Worm Gear Motors: Which One Fits Your Project?
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HyHaven carries two worm gear motors, the HH-370 and the HH-31ZY. They look similar on a shelf — small metal gearboxes, 12V or 24V DC, an output shaft that turns slowly and holds its position when the power goes off. But they are built for different sizes of job. Pick the wrong one and you either pay for torque you never use, or stall a mechanism that needed the bigger motor. This guide compares them on the numbers that decide the choice.
What Both Motors Share
Worm gearing gives both motors the same three traits:
Large reduction in a small box. A worm and wheel pack a high gear ratio into one compact stage, so the output turns far slower than the motor — and with far more torque.
Self-locking. When power is off, the worm drive holds the output shaft in place. A turntable stays where you left it; a curtain does not drift back down. Neither motor needs a brake for holding position under its rated load.
Low backlash. Both gearboxes are rated at backlash of 2° or less, so reversing direction does not produce a large dead zone. That matters for mechanisms that move back and forth, like display turntables and small positioning stages.
Both motors run on 12V or 24V DC, use a metal housing with an oil-impregnated bearing, and are rated for continuous DIY and light-duty use.
Side-by-Side Comparison
| HH-370 | HH-31ZY | |
|---|---|---|
| Price | $15.99 | $29.99 |
| Gearbox size | 46 × 32 mm | 58 × 40 mm |
| Weight | 150 g | 300 g |
| Output shaft | Ø6 mm D-shaft | Ø8 mm shaft |
| Motor power | 0.94 W (12V) / 0.95 W (24V) | 3.5 W |
| Max rated torque | 10.0 kgf·cm (≈0.98 N·m) | 25.0 kgf·cm (≈2.45 N·m) |
| Gear ratios | 11, from 40:1 to 5300:1 | 12, from 26.8:1 to 710:1 |
| Rated output speed range | 130 down to 1.0 RPM | 149.3 down to 5.6 RPM |
| Backlash | ≤2° | ≤2° |
| Max radial load | ≤1 kgf | ≤3 kgf |
| Max axial load | ≤0.7 kgf | ≤5 kgf |
| Max shaft press-in force | ≤10 kgf | ≤15 kgf |
The Deciding Differences
Torque is the headline gap. The 31ZY delivers up to 25.0 kgf·cm — two and a half times the 370's 10.0 kgf·cm. If your mechanism turns a loaded turntable, a rotisserie, or a small conveyor, that gap is the whole decision.
Size and weight run the other way. The 370's gearbox is 46 × 32 mm and 150 g — half the weight of the 31ZY and small enough to hide inside a display base, a model, or a tight curtain mechanism. When space is the constraint, the 370 wins even before price enters the picture.
Speed range differs at both ends. The 370 goes slower (down to 1.0 RPM at 5300:1) and is the pick for very slow, precise motion — a display that creeps, a mechanism that indexes once a minute. The 31ZY tops out faster (149.3 RPM at 26.8:1) and covers the middle range where most small automation lives.
Shaft and bearing loads follow size. The 31ZY's Ø8 mm shaft takes up to 3 kgf radial and 5 kgf axial load; the 370's Ø6 mm D-shaft is rated for 1 kgf radial and 0.7 kgf axial. If your load hangs off the shaft or pushes along it, check these numbers — they are easy to exceed with an overhung turntable.
Price follows capability. At $15.99 versus $29.99, the 370 is the low-cost option for light mechanisms; the 31ZY costs more because it moves more.
Which One Should You Pick?
| Your project | Pick |
|---|---|
| Small display turntable, model mechanism, light curtain, tight space | HH-370 |
| Very slow motion (a few RPM or less) | HH-370 (ratios up to 5300:1) |
| Loaded turntable, rotisserie, small conveyor, smart-home mechanism | HH-31ZY |
| Output speed in the 10–150 RPM band with real torque | HH-31ZY |
| Load hangs off the shaft or pushes along it | HH-31ZY (higher radial/axial ratings) |
| Budget first, load well under 10 kgf·cm | HH-370 |
A simple rule: if your load torque is comfortably under 10 kgf·cm and the mechanism is small, the 370 does the job for less money and less space. If you are anywhere near 10 kgf·cm, or the load is overhung, step up to the 31ZY — running a small motor at its limit shortens its life and risks stalling.
Two Things to Check Before Ordering
Check the ratio, not just the model. Both motors are sold by voltage (12V/24V) and gear ratio, and ratio decides output speed and torque. A 370 at 40:1 turns at 130 RPM with only 0.6 kgf·cm; the same motor at 950:1 turns at 5.5 RPM with the full 10.0 kgf·cm. Our ratio guides walk through the full tables for each motor.
Check the shaft load. Torque is not the only limit. If your turntable plate is heavy or mounted off-center, compare its radial and axial load against the table above before you buy.
FAQ
Can the 370 replace the 31ZY if I just need it to turn slowly?
Only if the load torque also fits. Slow does not mean weak — a heavy turntable at 5 RPM still needs the torque to move it. Match torque first, speed second.
Do both motors hold position with the power off?
Yes. Worm gearing is inherently self-locking on both models, within their rated loads. The shaft stays put when power is removed.
12V or 24V — does it change speed or torque?
Per the datasheets, the rated output speeds and torques are the same for the 12V and 24V versions of each motor. Choose the voltage that matches the rest of your system.
Can I drive either motor with a HyHaven controller kit?
Both motors are small DC loads (under 1 W and 3.5 W respectively), far below the controller kits' range — but check the kit's voltage matches your motor version (12V or 24V). For wiring basics, see our guide to wiring a linear actuator, and browse controllers and remote kits for the control side.
The Short Version
Small, light, slow, tight space: HH-370. Heavier load, faster middle range, overhung shaft: HH-31ZY. Match torque first, then speed, then size — in that order — and the choice makes itself.