Lathe Metalworking

Gear Hob Cutter

Re sharpening of Gear Hobs

The accuracy of the Gear cutting tools  depends largely on good Gear cutters resharpening and the 

performance of Cutter is very much affected by the type of resharpening carried out. 

If a Cutter is resharpened under incorrect working condition, it may at times result in tooth 

breakage. The vast majority of hobs are recoated after each 

resharpening operation with TiN or other more sophisticated films such as TiAlN and TiCN.  

Hobs, therefore, have to be prepared for the coating process carefully after they have 

been resharpened. A hob with a convex cutting face will produce a gear tooth with more material on the tip 

and at the root. This error may be tolerate on the workpiece un until a certain entity. 

To reduce it, however, it is firstly necessary to reduce the diameter of the Grinding Wheel 

and if this is not sufficient, the Grinding Wheel will have to be appropriately profiled. 

The profile error that is generated on the resharpening face must be examined separately. 

If we are sharpening a hob with helical gashes using a grinding wheel   that has a 

rectilinear cutting line, the face that is generated will be slightly crowned because of the 

interference of the grinding wheel with the helical gash. 

The larger the helix angle of the gash and the larger of the diameter of the grinding wheel, 

the greater this convexity of the resharpening face will be. 

Of course the size of this error also depends on the hob tooth depth. 

This is why resharpening machines which works helical hobs must be equipped with a 

special dressing unit to profile the grinding wheel, so as to generate the same convexity 

and compensate for the interference phenomenon. 

A hob with a convex cutting face will produce a gear tooth with more material on the tip 

and at the root. This error may be tolerate on the workpiece un until a certain entity. 

To reduce it, however, it is firstly necessary to reduce the diameter of the grinding wheel 

and if this is not sufficient, the grinding wheel will have to be appropriately profiled. 

 

For further information, please visit www.capital-tool.com or mail us at info@capital-tool.com

 

 

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Charles Lessig's Hob Reliever Eureka Balzer Gear Cutting