H-610-24P.. 24mm Champ Full Mortise Concealed Cylinder Hinge. Sold by the Each. The secret is in the wedge-action! In the open position the hinge has a set screw which expands the cylinder inside the hole. Just drill hole, insert and tighten the set screw! Machined solid brass with steel linkages Drill 24mm size holes to exact depth. 24mm diameter x 2″ long for 1-1/4″ to 1-1/2″ wood. 24mm=approximately 15/16″. Works great on things like butterfly table table leafs.