How to Make a Thumb for a Backhoe

Most small backhoes are limited to digging only.
Make a thumb for your backhoe.Make a thumb for your backhoe.
This is because the bucket of the backhoe has nothing to push against. If you attach a steel thumb to the backhoe arm on the opposite side of the bucket, you create an opposing thumb, just like the human hand. The thumb doesn't move, however. When the backhoe operator uses the hydraulic control to contract the bucket, it pinches against the thumb and works just like a human hand to pick up objects.

Step 1

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.

Step 2

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.

Step 3

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.

Step 4

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

Step 5

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.

Step 6

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.

Things You Will Need

  • 2 steel plates, 1/4-by-6-by-18-inches
  • 2 steel plates, 1/4-by-6-by-24-inches
  • Arc welder
  • Electric drill
  • 3/4-inch drill bit
  • 3/4-inch bolts, 1 1/2-inches long
  • Nuts and washers
  • 3/4-inch socket
  • Ratchet
  • Steel plate, 1/4-by-6-by-12-inches
  • Hand clamp

About the Author

Specializing in hardwood furniture, trim carpentry, cabinets, home improvement and architectural millwork, Wade Shaddy has worked in homebuilding since 1972. Shaddy has also worked as a newspaper reporter and writer, and as a contributing writer for Bicycling Magazine. Shaddy began publishing in various magazines in 1992, and published a novel, “Dark Canyon,” in 2008.