Gear hobbing is a precision machining process that is used to create gears and other similar parts, the top manufacturers of Gear Hobbing machines include:

1. Gleason: A global company that produces a wide range of gear production machinery, including hobbing machines, shaping machines, and grinding machines.
2. Kapp: A German company that specializes in the production of gear manufacturing machinery, including hobbing machines, grinding machines, and gear measuring equipment.
3. Reishauer: A Swiss company that specializes in the production of gear grinding and gear hobbing machines, as well as gear inspection equipment.
4. GLEASON-PFAUTER: A German company that designs and manufactures a wide range of gear production machinery, including hobbing machines, shaping machines, and grinding machines.
5. Liebherr: A German company that designs and manufactures a wide range of gear production machinery, including hobbing machines, shaping machines, and grinding machines.
6. Monforts: A German company that designs and manufactures a wide range of gear production machinery, including hobbing machines, shaping machines, and grinding machines.
7. WMW: A German company that manufactures a wide range of gear hobbing machines and gear grinding machines.
8. Hoefler: A German company that designs and manufactures a wide range of gear production machinery, including hobbing machines, shaping machines, and grinding machines.
9. Koepfer: A German company that designs and manufactures a wide range of gear production machinery, including hobbing machines, shaping machines, and grinding machines.
10. Star SU: An American company that designs and manufactures a wide range of gear production machinery, including hobbing machines, shaping machines, and grinding machines.

Like previously mentioned, this list is not an exhaustive one and can vary depending on location, product line, and market scenario. These manufacturers also have different ranges of products and focus on different market segments.