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Last week I showed how to modify — using only two copper shims — a tap wrench handle and turn it into a high torque handle to drive augers. This week I will show how to improve this wrench even further by adding a chuck that will hold the bits and provide a stronger fit plus, it will allow you to mount the bits faster and conveniently. 

The trick here is to find a drill chuck and connect an SDS Plus adapter/mandrel to it. The SDS Plus mandrel fits almost perfectly in between the tap wrench’s jaws, allowing you to utilize the chuck and accommodate drill bits and auger bits of your choosing. 

The chuck set that I bought came with three mandrels; one of them was the SDS Plus which has a square-ish cross-section that fits between the jaw of the tap wrench. First, remove the locking screw from the mandrel and then thread it into the chuck. Then insert the screw between the three jaws and tighten it. Remember that this it s a left-hand or reverse thread screw.

This is the SDS Plus mandrel after being threaded into the 1/2″ chuck.

These mandrels that came with this kit might prove handy, too, one day. Notice their locking screw with its left-hand thread.

Now insert the mandrel between the wrench jaws and tighten them so they fit nicely over the mandrel shaft’s keyseats (the oval vaulted grooves). I provided many images to help you see what I mean. Remember to tighten the jaws with a tool such as an awl or a drill bit inserted into the moving-jaw tightening handle. 


Your new chuck handle is ready and could be used with wide augers, long twist bits, and any bit that fits into the ½” chuck.

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