Wooden Farm Toys for Haymaking

Step 2 Rear of the tractor

 In addition to the piece for the tractor frame, the other key piece (in addition to the wheels) is the axle member.  I cut a notch in the underside of the tractor frame and in the upper side of the axle member to make a tight fitting lap joint.  The red lines define the notch cut into the axle member.  I drilled a 3/16 inch hole across the axle member that also goes through part of the tractor frame.  When the 3/16 inch axle rod is inserted (yellow line), the tractor's main pieces are locked together.