Lowell Corporation Mechanical Ratchet Clutches, Model 73

Rugged and reliable for heavy-duty applications
Lowell ratchet clutches are designed from standard bodies, gears, pawls, and springs. Forces are applied in an optimum manner between the solid steel gear and hefty pawl so that loads are in compression rather than in shear. Gears are a low-carbon steel. Rugged tooth design as large contact area with pawl.

  • Mounting holes provided in body
  • Keyways are per ANSI/ASME B17.1
  • Lubrication is recommended after every 1200 hours of operation
  • Specials may be ordered with size, shape, and tooth arrangements of your choice
  • Fully locked neutral position
  • Free running neutral position available on request
  • Durable, cast iron construction
  • Custom models available
  • 100% made in USA
ImageOpeningPart NumberGear TeethMax TorqueOverrunning SpeedMaterialABCDEFGHJMeasurement Systemhf:att:pa_socket-openinghf:att:pa_gear-teethhf:att:pa_max-torquehf:att:pa_overrunning-speedhf:att:pa_materialhf:att:pa_ahf:att:pa_bhf:att:pa_chf:att:pa_dhf:att:pa_ehf:att:pa_fhf:att:pa_ghf:att:pa_hhf:att:pa_jhf:att:pa_measurement-system
Model 73 Ratchet Clutch - Square Opening
1/2" Sq73901-9320820500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-2-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
5/8" Sq73901-9321020500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard5-8-sq-220500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
11/16" Sq73901-9321120500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard11-16-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
3/4" Sq73901-9321220500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard3-4-sq-220500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
7/8" Sq73901-9321420500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard7-8-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
1" Sq73901-9321620500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
1-1/16" Sq73901-9321720500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-1-16-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
1-1/8" Sq73901-9321820500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-1-8-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Square Opening
13 mm Sq73901-M321320500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric13-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
16 mm Sq73901-M321620500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric16-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
17 mm Sq73901-M321720500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric17-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
19 mm Sq73901-M321920500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric19-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
20 mm Sq73901-M322020500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric20-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
22 mm Sq73901-M322220500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric22-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
24 mm Sq73901-M322420500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric24-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
25 mm Sq73901-M322520500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric25-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
27 mm Sq73901-M322720500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric27-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Square Opening
28 mm Sq73901-M322820500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric28-mm-sq20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
3/4" Hex73901-9331220500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard3-4-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Hex Opening
7/8" Hex73901-9331420500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard7-8-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Hex Opening
1" Hex73901-9331620500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Hex Opening
1-1/8" Hex73901-9331820500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-1-8-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Hex Opening
1-1/4" Hex73901-9332020500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-1-4-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Hex Opening
19 mm Hex73901-M331920500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric19-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
22 mm Hex73901-M332220500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric22-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
24 mm Hex73901-M332420500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric24-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
25 mm Hex73901-M332520500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric25-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
27 mm Hex73901-M332720500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric27-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
28 mm Hex73901-M332820500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric28-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
30 mm Hex73901-M333020500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric30-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
32 mm Hex73901-M333220500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric32-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Hex Opening
36 mm Hex73901-M333620500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric36-mm-hex20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Bore Opening
3/4" Bore73901-9311220500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard3-4-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Bore Opening
1" Bore73901-9311620500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Bore Opening
1-1/8" Bore73901-9311820500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-1-8-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Bore Opening
1-1/4" Bore73901-9312020500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Standard1-1-4-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64standard
Model 73 Ratchet Clutch - Bore Opening
19 mm Bore73901-M311920500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric19-mm-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Bore Opening
25 mm Bore73901-M312520500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric25-mm-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Bore Opening
28 mm Bore73901-M312820500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric28-mm-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric
Model 73 Ratchet Clutch - Bore Opening
32 mm Bore73901-M313220500 lb-ft100 rpmCast Iron, Steel4"3-1/8"1-5/16"2-7/16"1-3/16"3-1/4"1-13/16"2-3/8"21/64"Metric32-mm-bore20500-lb-ft100-rpmcast-iron steel43-1-81-5-162-7-161-3-163-1-41-13-162-3-821-64metric