DOUBLE REDUCTION SERIES
Up to 10,000 lb Capacity
When you need to lift, lower or position a heavy load, Thern’s spur gear hand winches are designed to deliver excellent performance and long life, no matter what your application.
QUICK FACTS
- Machine-cut spur gears
- Variety of configurations
- Adjustable handles
- Corrosion resistant
- Two-Year Limited Warranty
SERIES MODELS
- M452/M452B
- M452B-A
- M492/M492B
- M492-12/M492B-12
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If you’re not sure what product you need and would like a quote, please fill out a request form.

Machine Cut Spur Gears
Automatic Brake Models
Corrosion Resistant
Bronze and Radial Ball Bearings
Large Diameter Drums
Spring Loaded Ratchets
Steel Gear Covers
Adjustable Handles
Two-Year Warranty
Spur Gear Double Reduction Hand Winches - Metric
Spur Gear Double Reduction Hand Winches Performance Characteristics — Metric |
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Load Rating |
Drum Capacity1 |
|||||||||||
Model No. |
Description |
1st |
Mid |
Full |
Wire Rope Dia. |
1st |
Mid |
Full |
Sgl Gear Ratio |
Dbl Gear Ratio |
Force2 to Lift 1000 lb |
Approx. |
(kg) |
(kg) |
(kg) |
(mm) |
(m) |
(m) |
(m) |
(kg) |
(kg) |
||||
M452 |
4000 lb — marine duty |
1814 |
1496 |
1133 |
6.3 |
7.0 |
39.6 |
91.4 |
4.42:1 |
19.54:1 |
4.5 |
38 |
(for pulling only) |
7.9 |
5.4 |
27.1 |
60.9 |
(dbl gear) |
|||||||
9.5 |
4.2 |
19.5 |
42.6 |
|||||||||
M452B |
4000 lb — marine duty |
1814 |
1496 |
1133 |
6.3 |
7.0 |
39.6 |
91.4 |
— |
19.54:1 |
4.5 |
42 |
with brake (for lifting only) |
7.9 |
5.4 |
27.1 |
60.9 |
(dbl gear) |
|||||||
9.5 |
4.2 |
19.5 |
42.6 |
|||||||||
M452B-A |
4000 lb — marine duty |
1814 |
1496 |
1133 |
6.3 |
3.9 |
25.2 |
57.9 |
— |
19.54:1 |
4.5 |
38 |
with brake (for lifting) |
7.9 |
2.7 |
17.0 |
36.5 |
(dbl gear) |
|||||||
4-inch drum width |
9.5 |
2.1 |
12.1 |
27.1 |
||||||||
M492 |
10,000 lb — marine duty |
4535 |
3356 |
2449 |
7.9 |
8.2 |
73.1 |
164.5 |
5.00:1 |
25.00:1 |
3.6 |
76 |
(for pulling only) |
9.5 |
6.4 |
51.8 |
118.8 |
(dbl gear) |
|||||||
12.7 |
4.5 |
30.4 |
70.1 |
|||||||||
M492B |
10,000 lb — marine duty |
4535 |
3356 |
2449 |
7.9 |
8.2 |
73.1 |
164.5 |
— |
25.00:1 |
3.6 |
79 |
with brake (for lifting) |
9.5 |
6.4 |
51.8 |
118.8 |
(dbl gear) |
|||||||
12.7 |
4.5 |
30.4 |
70.1 |
|||||||||
M492-12 |
10,000 lb — marine duty |
4535 |
3356 |
2449 |
7.9 |
14.0 |
115.8 |
259.0 |
5.00:1 |
25.00:1 |
3.6 |
80 |
(for pulling only) |
9.5 |
11.2 |
82.2 |
185.9 |
(dbl gear) |
|||||||
12-inch drum width |
12.7 |
8.2 |
48.7 |
109.7 |
||||||||
M492B-12 |
10,000 lb — marine duty |
4535 |
3356 |
2449 |
7.9 |
14.0 |
115.8 |
259.0 |
— |
25.00:1 |
3.6 |
87 |
with brake (for lifting) |
9.5 |
11.2 |
82.2 |
185.9 |
(dbl gear) |
|||||||
12-inch drum width |
12.7 |
8.2 |
48.7 |
109.7 |
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MB451 |
Disc brake only for M452 (for lifting) |
6 |
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MB491 |
Disc brake only for M492 and M492-12 (for lifting) |
7 |
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Please contact factory or nearest Thern distributor for firm fixed price and delivery. |
IMPORTANT: It is the owner’s or operator’s responsibility to determine the suitability of the equipment to its intended use. Study all applicable codes, manuals and regulations. Be sure to read the Owner’s Manual supplied with the equipment before operating it.
Spur Gear Double Reduction Hand Winches Performance Characteristics |
||||||||||||
Load Rating |
Drum Capacity1 |
|||||||||||
Model No. |
Description |
1st |
Mid |
Full |
Wire Rope Dia. |
1st |
Mid |
Full |
Sgl Gear Ratio |
Dbl Gear Ratio |
Force2 to Lift 1000 lb |
Approx. |
(lb) |
(lb) |
(lb) |
(in) |
(ft) |
(ft) |
(ft) |
(lb) |
(lb) |
||||
M452 |
4000 lb — marine duty |
4000 |
3300 |
2500 |
1/4 |
23 |
130 |
300 |
4.42:1 |
19.54:1 |
10 |
83 |
(for pulling only) |
5/16 |
18 |
89 |
200 |
(dbl gear) |
|||||||
3/8 |
14 |
64 |
140 |
|||||||||
M452B |
4000 lb — marine duty |
4000 |
3300 |
2500 |
1/4 |
23 |
130 |
300 |
— |
19.54:1 |
10 |
91 |
with brake (for lifting only) |
5/16 |
18 |
89 |
200 |
(dbl gear) |
|||||||
3/8 |
14 |
64 |
140 |
|||||||||
M452B-A |
4000 lb — marine duty |
4000 |
3300 |
2500 |
1/4 |
13 |
83 |
190 |
— |
19.54:1 |
10 |
83 |
with brake (for lifting) |
5/16 |
9 |
56 |
120 |
(dbl gear) |
|||||||
4-inch drum width |
3/8 |
7 |
40 |
89 |
||||||||
M492 |
10,000 lb — marine duty |
10,000 |
7400 |
5400 |
5/16 |
27 |
240 |
540 |
5.00:1 |
25.00:1 |
8 |
166 |
(for pulling only) |
3/8 |
21 |
170 |
390 |
(dbl gear) |
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1/2 |
15 |
100 |
230 |
|||||||||
M492B |
10,000 lb — marine duty |
10,000 |
7400 |
5400 |
5/16 |
27 |
240 |
540 |
— |
25.00:1 |
8 |
173 |
with brake (for lifting) |
3/8 |
21 |
170 |
390 |
(dbl gear) |
|||||||
1/2 |
15 |
100 |
230 |
|||||||||
M492-12 |
10,000 lb — marine duty |
10,000 |
7400 |
5400 |
5/16 |
46 |
380 |
850 |
5.00:1 |
25.00:1 |
8 |
175 |
(for pulling only) |
3/8 |
37 |
270 |
610 |
(dbl gear) |
|||||||
12-inch drum width |
1/2 |
27 |
160 |
360 |
||||||||
M492B-12 |
10,000 lb — marine duty |
10,000 |
7400 |
5400 |
5/16 |
46 |
380 |
850 |
— |
25.00:1 |
8 |
190 |
with brake (for lifting) |
3/8 |
37 |
270 |
610 |
(dbl gear) |
|||||||
12-inch drum width |
1/2 |
27 |
160 |
360 |
||||||||
MB451 |
Disc brake only for M452 (for lifting) |
13 |
||||||||||
MB491 |
Disc brake only for M492 and M492-12 (for lifting) |
15 |
||||||||||
Please contact factory or nearest Thern distributor for firm fixed price and delivery. |
IMPORTANT: It is the owner’s or operator’s responsibility to determine the suitability of the equipment to its intended use. Study all applicable codes, manuals and regulations. Be sure to read the Owner’s Manual supplied with the equipment before operating it.
Vertical Lead Block
Vertical Lead Block Series
Wire Rope Assemblies

Visit our Rope and Rigging product page for more information.
Hand Winches Dimensions — Models M452 and M492

Spur Gear Double Reduction Hand Winches — Imperial Dimensions |
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Model No. |
Drum Dia. |
Flange Dia. |
Drum Width |
A |
B |
C |
D |
E |
F |
G1 |
H1 |
J |
K |
L |
M |
S (hole dia.) |
T |
V |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
(in) |
|
M452 |
4.00 |
8.50 |
6.38 |
15.25 |
22.00 |
10.69 |
5.81 |
5.81 |
14.81 |
18.62 |
24.44 |
6.75 |
9.50 |
11.25 |
12.50 |
.56 |
.25 |
— |
M452B |
4.00 |
8.50 |
6.38 |
15.25 |
21.90 |
10.69 |
5.81 |
5.81 |
16.43 |
18.38 |
24.19 |
6.75 |
9.50 |
11.25 |
12.50 |
.56 |
.25 |
— |
M452B-A |
4.00 |
8.50 |
4.00 |
15.25 |
19.62 |
10.83 |
5.81 |
5.81 |
14.06 |
18.38 |
24.19 |
4.50 |
7.12 |
11.25 |
12.50 |
.56 |
.25 |
— |
M492 |
5.00 |
12.38 |
7.62 |
20.38 |
25.12 |
14.00 |
7.50 |
7.50 |
18.44 |
22.50 |
30.00 |
8.00 |
12.00 |
15.50 |
17.00 |
.81 |
.38 |
— |
M492B |
5.00 |
12.38 |
7.62 |
20.38 |
25.00 |
14.00 |
7.50 |
7.50 |
19.53 |
18.50 |
26.00 |
8.00 |
12.00 |
15.50 |
17.00 |
.81 |
.38 |
— |
M492-12 |
5.00 |
12.38 |
12.00 |
20.38 |
29.50 |
14.00 |
7.50 |
7.50 |
22.82 |
22.50 |
30.00 |
8.00 |
16.38 |
15.50 |
17.00 |
.81 |
.38 |
12.38 |
M492B-12 |
5.00 |
12.38 |
12.00 |
20.38 |
29.38 |
14.00 |
7.50 |
7.50 |
23.90 |
18.50 |
26.00 |
8.00 |
16.38 |
15.50 |
17.00 |
.81 |
.38 |
12.38 |
Dimensions are for reference only and subject to change without notice. |
Spur Gear Double Reduction Hand Winches — Metric Dimensions |
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Model No. |
Drum Dia. |
Flange Dia. |
Drum Width |
A |
B |
C |
D |
E |
F |
G1 |
H1 |
J |
K |
L |
M |
S (hole dia.) |
T |
V |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
(mm) |
|
M452 |
101.6 |
215.9 |
162.0 |
387.3 |
558.8 |
271.5 |
147.5 |
147.5 |
376.1 |
472.9 |
620.7 |
171.4 |
241.3 |
285.7 |
317.5 |
14.2 |
6.3 |
— |
M452B |
101.6 |
215.9 |
162.0 |
387.3 |
556.2 |
271.5 |
147.5 |
147.5 |
417.3 |
466.8 |
614.4 |
171.4 |
241.3 |
285.7 |
317.5 |
14.2 |
6.3 |
— |
M452B-A |
101.6 |
215.9 |
101.6 |
387.3 |
498.3 |
275.0 |
147.5 |
147.5 |
357.1 |
466.8 |
614.4 |
114.3 |
180.8 |
285.7 |
317.5 |
14.2 |
6.3 |
— |
M492 |
127 |
314.4 |
193.5 |
517.6 |
638.0 |
355.6 |
190.5 |
190.5 |
468.3 |
571.5 |
762 |
203.2 |
304.8 |
393.7 |
431.8 |
20.5 |
9.6 |
— |
M492B |
127 |
314.4 |
193.5 |
517.6 |
635 |
355.6 |
190.5 |
190.5 |
496.0 |
469.9 |
660.4 |
203.2 |
304.8 |
393.7 |
431.8 |
20.5 |
9.6 |
— |
M492-12 |
127 |
314.4 |
304.8 |
517.6 |
749.3 |
355.6 |
190.5 |
190.5 |
579.6 |
571.5 |
762 |
203.2 |
416.0 |
393.7 |
431.8 |
20.5 |
9.6 |
314.4 |
M492B-12 |
127 |
314.4 |
304.8 |
517.6 |
746.2 |
355.6 |
190.5 |
190.5 |
607.0 |
469.9 |
660.4 |
203.2 |
416.0 |
393.7 |
431.8 |
20.5 |
9.6 |
314.4 |
Dimensions are for reference only and subject to change without notice. |
IMPORTANT: It is the owner’s or operator’s responsibility to determine the suitability of the equipment to its intended use. Study all applicable codes, manuals and regulations. Be sure to read the Owner’s Manual supplied with the equipment before operating it.
Disc Brake Dimensions — Models MB451 and MB491
Disc Brake Dimensions — Models MB451/MB491 |
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Model No. |
N |
P |
Q1 |
R |
U |
V |
||||||
(in) |
(mm) |
(in) |
(mm) |
(in) |
(mm) |
(in) |
(mm) |
(in) |
(mm) |
(in) |
(mm) |
|
MB451 |
4.97 |
126.2 |
10.44 |
265.1 |
21.25 |
539.7 |
4.87 |
123.6 |
2.44 |
61.9 |
8.62 |
218.9 |
MB491 |
5.15 |
130.8 |
10.62 |
269.7 |
21.38 |
543.0 |
4.87 |
123.6 |
2.44 |
61.9 |
10.56 |
268.2 |
Dimensions are for reference only and subject to change without notice. |
IMPORTANT: It is the owner’s or operator’s responsibility to determine the suitability of the equipment to its intended use. Study all applicable codes, manuals and regulations. Be sure to read the Owner’s Manual supplied with the equipment before operating it.