How to Modify Your Impact Wrench to Get More Torque

What You'll Need
Allen wrenches
Adjustable wrench

Modifying your impact wrench to get more torque is something that is never recommended by manufacturers. You should not try and modify the torque settings beyond the limits recommended by the manufacturer. If you have a torque wrench that isn’t capable of solving the task at hand, it is always better to buy/borrow a new impact wrench. If you choose to go ahead with modifications to get more torque, this is what you need to do:

Step 1 - Creating the Gaps on the Impact Wrench

Disassemble the impact wrench by removing the rear plate cover without damaging the paper gasket. Pull out the rotor and cylinder for modification. You need to grind a new shape onto the cylinder ports without losing too much metal.

The cylinder has to be ground on the reverse side as well.

The exhaust ports on the cylinder need to be opened to reveal the end plate, which also needs grinding to increase the size of the inlet ports. Ideally, both inlet ports should be cut to the same size, leaving space for the screw hole.

Step 2 - First Milestone Reached

Once you have cut the end plates, you can retrace your steps to put the impact wrench back together. The modifications made to the wrench will show considerable difference in the output, enabling you to tackle bigger tasks that were previously out of range.

Step 3 - Still not Enough

If the newly modified impact wrench is still not delivering the torque you need, carry out more modifications. Instead of re–assembling the wrench, carry on from the end plate–modification stage. Remove the power regulator knob and increase the dimensions of the biggest hole on it.

On the cover plate, cut 2 ribs along the sides before moving onto the inlet fittings.

Step 4 - Inlet Improvements

Cut the rubber seal to the same diameter as the metal seat’s hole it sits against. Remove some material from the trigger pin to improve the air passageway as well.

Remove the reversing valve from the impact wrench before grinding out 2 air pressure holes, matching the bottom edges of the end plate and the cylinder. Drill out 2 air pressure holes, but make sure you only drill to the current depth to avoid breaking into the other parts of the wrench.

Cut the paper gasket to match the new openings before moving to the top of the wrench. Drill into the casing to ensure that the cylinder exhaust ports open up to the atmosphere above.

Step 5 - Cleaning Up

Before reassembly, make sure all your parts are clean and well lubricated as you begin the process of putting the impact wrench back together. Retrace your steps exactly as you would to put your impact wrench together and make sure everything fits right into place.