GearHeads Corner

I plan to install a clamp screwed to a circular gear to fix the gear securely to its shaft.  I'd still like to have spokes on the gear but need to be sure the hub diameter is sufficient to accommodate the clamp screws.  Hub size is given as a ratio.  Is there a simple formula to give the hub diameter based on one or more of the dimensions displayed for the gear.  Perhaps I'm missing something obvious but I've tried to determine a formula without success.  Can you help please.  Cheers

On closer examination the formula looks to be

HubDiameter=PitchDiameter x Ratio/100 + HoleDiameter

If you could confirm I would appreciate it
Thanks

Hi:

Yes, you got it. Most of the formulas are based on pitch curve and requested hole diam..

Art