RE-NEW MACHINE & MAINTENANCE, A Division of Repair Parts, Inc.
2415 Kishwaukee Street, Rockford, Illinois 61104    Phone: (815) 968-4499   Fax: (815) 968-4694

The One-Stop Shop for
Barber-Colman Machine Tools

  • Machine tool reconditioning
  • Repair and replacement parts
  • Factory trained service
  • Training -- operator, set up, or maintenance -- in your facility or ours
  • Gear Machine Sales -- We have reconditioned hobbers & sharpeners in stock -- can be seen under power
  • Hob sharpening
  • Consulting and appraisals

"Tips & Techniques" - April, 2002

We have noticed recently, that many of the hobs being sent to us for sharpening show excessive wear in certain areas of the tool. Therefore we feel that it is a good time to emphasize proper hob shifting.

Hob Shift Formulas

The approximate amount of shift suggested is based on applying standard machineability rates. Since hob wear is influenced by many variables the following formula can only be considered as an approximate value.

Formula 1

Formula 2
Length of Available Hob Shift

The total axial hob shift for a conventional full generating hob is limited to the active face width minus the approximate sum of the rough and finish areas.

Spur Tooth Form Application
Formula 3

Formula 4
Helical Tooth Form Application
Formula 5

Formula 6

When using these formulas please remember that they are only guidelines and there are many factors that can influence Hob Wear. If you have any questions concerning these formulas please feel free to contact me at rpi@repair-parts-inc.com.


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