Worm gears use screw threads to make large reductions to shaft speed while transmitting motion at a right angle. They transmit motion from worm to gear and cannot be reversed. For gears and worms to mesh correctly, they must have the same pressure angle and pitch/module. These worms are compatible with plastic worm gears.

Speed ratio is the ratio by which output shaft speed is reduced. As speed decreases, torque increases.

Cast iron gears are strong and durable.

Bronze gears have low friction and dissipate heat better than cast iron gears to provide a long service life for both the gear and the worm. They’re also more corrosion resistant than cast iron gears.

Aluminum-bronze gears have excellent wear resistance.

For technical drawings and 3-D models, click on a part number.

Metric Worm Gears

Gear

										Hub
Module	Speed Ratio	Number of Teeth	Pressure Angle	Gear Pitch Dia., mm	For Number of Thread Starts	OD, mm	Face Wd., mm	Overall Wd., mm	For Shaft Dia., mm	Dia., mm	Wd., mm	Material	For Thread Direction	Teeth Heat Treatment	Teeth Fabrication		Each
Round Bore—Cast Iron
1.5	40:1	40	20°	60	1	64.5	12	22	12	30	10	Cast Iron	Right Hand	Not Hardened	Not Ground	000000000	000000
Round Bore—Bronze
1.5	40:1	40	20°	60	1	64.5	12	22	12	30	10	Bronze	Right Hand	Not Hardened	Not Ground	000000000	00000
Round Bore—Aluminum-Bronze
1.5	40:1	40	20°	60	1	64.5	14	24	12	35	10	Aluminum-Bronze	Right Hand	Not Hardened	Not Ground	000000000	000000

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About Gears

Metal Worms and Worm Gears