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TONE GPTN-391E Turn-of-Nut Wrench

The GPTN-391E turn-of-nut wrench features an integrated reverse kit, overload protection, clockwise and counterclockwise torque control, setting dial, LED indicator lights, and a maximum torque of 3,700 ft-lb. Our line of turn-of-nut wrenches are designed for the turn-of-nut method and automatically tightens the bolt assembly to the preset rotation.

Fully Tensioned Structural Bolts:

A325 – 1-1/4”, 1-3/8″, 1-1/2″

A325M – M30, M33

A490 – 1-1/4″, 1-3/8″, 1-1/2″

A490M – M30, M33

Maximum Torque:

3,700 ft–lb. (5,000 N-m)


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Model TONE GPTN-391E
Voltage 110-120 V
Maximum Current 14 A
Maximum Power  1,600 W
Frequency 50-60 Hz
Maximum Torque  3,700 ft–lb. (5,017 N-m)
Controllable Angle Range 90-240°
No-load Speed 2.5 rpm
Tool Weight 24.5 lb. (11.1 kg)
Repeated Accuracy ±10°

Available Accessories 

Inch Sockets Metric Sockets
Nut Dimension Across Flats Heavy-Hex Bolt Diameter Nut Dimension Across Flats Heavy-Hex Bolt Diameter Finished Hex Bolt Diameter
2″ 1 – 1/4″ 50 mm M30 M33
2 – 3/16″ 1 – 3/8″ 55 mm M33 M36
2 – 3/8″ 1 – 1/2″

Bar Sockets


Helpful resources:

Instructional Manual

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Kind words from our customers:

  • I have enjoyed working with GWY. Their people know their product well. Their prompt response and delivery of the product is as good as any service Ogeechee Steel has ever had the pleasure of doing business with.”

  • From choosing the right equipment for each job’s unique requirements to problem solving in the field, GWY is always willing to go out of the way to find a solution. Mix that customer service in with their technical expertise and easy-to-use tools, they really help make bolt up easy.”


Because the TN-tool is rotation based, can it do smaller sizes than what it is recommended for?

No, because for the tool to start counting the degrees of rotation, a certain torque must be met.

Does my TN wrench need to be calibrated?

No, turn of nut (TN) wrenches do not require calibration. TN tools are rotation tools, and they measure rotation mechanically. These tools either work or they do not. You can match mark to show they are functioning properly.

Are the same size sockets interchangeable between different tools?

Typically, the answer is no but there are exceptions.  The only interchangeable sockets for current model shear wrenches are between the GV-301ZA and the GVC-301EZ. The Older models like the S-60EZA share sockets with their newer models like the S-61EZ. The same is true for the S-90EZ and GS-91EZ as well as the S-110EZ and the GS-111EZ. There are a few TN tools that share sockets with each other such as the TN-20EZ and the TN-22EZ as well as the TN-30EZ and the TN-33EZ. The GNR series can share sockets with some of the TN tools. The GNR-31E, 51E, & 81E can use the TN-20EZ/22EZ bar sockets instead of impact sockets. The GNR-121E can use the bar sockets of the TN-24EZA and the GNR-211E can use the bar sockets of the TN-30EZ/33EZ. The GNR’s can also share impact sockets that have their correct drive size.