Abstract: A tool mounting assembly for a gear hobbing machine is disclosed as being mounted between a drive spindle and an outboard bearing support in axial alignment with said drive spindle. The tool mounting assembly comprises a first coupling unit for detachably connecting one end of a hob in driving engagement with said drive spindle, and a second coupling unit for detachably connecting the other end of said hob to said outboard bearing support. The outboard support unit includes a plunger rotatably mounted in the bearing support and axially movable between a hob coupling position and an unload position, and has a drive means for selectively moving the plunger between said hob coupling and unload positions. The second coupling unit includes a first portion secured to the other end of said hob and a second portion secured to said plunger, and includes axial nesting means for self centering the other end of the hob.