How to Make a Thumb for a Backhoe

Place the short plate flat on the ground. Place the other two plates on their sides, on top of the bottom plate, flush with the sides. The plates on their sides should be extended out past the end of the bottom plate by 6 inches. You should be looking at a rectangular box without a top with a "U" shape.

Weld the three plates together. The extended part of the ends will slip over the arm of the backhoe. Drill through both corners of the extended ends. This is where the thumb will attach to the arm. Use an electric drill and 3/4-inch drill bit.

Slip the extended arms of the plates over the end of the backhoe arm, 18 inches from the point where the bucket attaches to the arm. Tilt the thumb 30 degrees in the direction of the bucket. Using the holes in the thumb as a guide, drill through the sides of the backhoe arm on both sides.

Insert bolts through the holes. Place nuts and washers on the bolts and tighten them with a 3/4-inch socket and ratchet.

Hold the remaining steel plate up under the thumb. This will be the brace. Position it at a 30-degree angle from the top of the thumb to the bottom side of the backhoe arm. Using a hand clamp, clamp it in place to the bottom of the arm.

Weld the bottom of the brace to the thumb. Drill straight up through the top of the steel, through the bottom of the backhoe arm. Insert a bolt through the hole and tighten to secure the thumb to the arm.