Hilti SIW 20-22 3/4 in High-Torque Cordless Impact Wrench

The Hilti SIW 20-22 is Hilti’s most powerful cordless impact wrench: a 3/4 in square-anvil tool with 2250 Nm maximum torque and 3000 Nm nut-busting torque in a 3.81 kg body. It ships with Hilti’s Quick lock socket-holding system, which keeps sockets secured and addresses the danger of sockets dropped from height.

The highest-torque Hilti cordless wrench for structural steel

Hilti lists bolting steel for primary and secondary structures, handrails, racking and machinery with high-tensile bolts up to M30 and pre-tightening up to M36, and loosening large rusty bolts for maintenance, operation and repair. In inch terms the page gives up to 1-3/16 in bolts with pre-tightening up to 1-3/8 in. That puts it in the class of steel erection, wind and telecom tower work, and plant maintenance where fasteners are large.

Two speed modes run 0 to 1,000 rpm and 0 to 1,125 rpm no-load with up to 2,000 and 2,250 impacts per minute. The built-in LED light, low-vibration design and a durable brushless motor are the main stated benefits. The UAE page lists a case kit (item 2428744) with the wrench, medium and large Quick lock sockets assemblies and a tool case.

Technical specifications

Selecting between the SIW 8-22, SIW 10-22 and SIW 20-22

The three larger Hilti wrenches differ by anvil and torque: the SIW 8-22 uses a 1/2 in friction ring with 1650 Nm nut-busting torque, the SIW 10-22 a 3/4 in through-hole anvil with 2000 Nm, and the SIW 20-22 a 3/4 in square anvil with 3000 Nm. Pick the tool for the largest fastener you must break loose, not the average one.

As with every impact wrench, the Hilti data warns against use where an exact torque or maximum torque is specified. For flange bolting to a stress or preload specification, run nuts down with the wrench and tighten with a calibrated tool. When enquiring, state the batteries and charger, socket sizes and whether the Quick lock accessories in the case kit are sufficient for your bolt range.

Hilti impact wrench range by anvil and torque

Maximum torque values are quoted as printed on the Hilti UAE pages, where footnotes define the test condition of each figure.

Before the first job: setup and socket checks

Use only impact-rated sockets with the correct 3/4 in square drive, and check each socket for cracks, worn drive corners and a proper fit before it is fitted to the anvil. Make sure the Quick lock system is engaged so that the socket is held securely, especially when working at height on steel structures or towers. Choose the speed mode for the job: the lower mode gives more control when running down nuts and on smaller fasteners, while the higher mode is suited to breaking loose large or seized bolts. Confirm that the battery and charger combination planned for the tool is the one listed in the Hilti operating instruction.

Using the SIW 20-22 safely on site

An impact wrench of this class produces strong reaction forces when a bolt breaks loose or seats suddenly. Hold the tool with both hands, keep a firm stance and avoid working from unstable ladders or positions where a sudden twist could cause a fall. Wear hearing protection given the sound pressure level in the table, as well as eye protection and gloves suited to the work. When working at height, follow site rules for securing tools and accessories against dropping. As stated above, do not rely on the wrench for final tightening where a defined torque or preload is required; finish those joints with a calibrated torque tool and record the values according to the project’s bolting procedure.

Working in Oman and GCC heat and dust

Steel erection, tower and plant maintenance work in the Gulf often takes place in direct summer sun. Keep the tool and batteries out of direct sunlight when they are not in use, store them in shade or in the case, and respect the operating and storage temperature limits in the table; a battery left in a closed vehicle can quickly exceed them. Allow hot batteries to cool before charging. Sand and fine dust can enter the tool through cooling openings and settle around the anvil, so blow off or wipe the tool at the end of each shift and keep sockets clean and lightly protected against corrosion, particularly on coastal and offshore sites where salt air is present.

Routine care

Inspect the anvil and the Quick lock area for wear or damage, check the housing for cracks after any drop, and remove the tool from service if it behaves abnormally. Servicing beyond cleaning and visual checks should be done as described in the Hilti operating instruction.

Documents and quotation

Request pricing and availability for the SIW 20-22 from Seven Star LLC, an independent supplier in Muscat serving Oman and the GCC. Please include the application, the supply (voltage and plug, or battery size and charger) and the quantity. The manufacturer’s multilingual operating instruction is attached for review before purchase; it is a manual rather than a datasheet. Browse more fastening tools in the Material Handling & Lifting Equipment category.