Hi,
I have recently come into the world of designing spur gears, by using an involute design method. One thing that I am unsure on is the "dedendum base circle relationship". I have searched for this term and cannot find any information about this, and wondered if anyone could explain this or point me in the right direction.
Thanks
You may find some information under the topic of "minimum number of teeth". When the base circle, equal to the cosine of the pressure angle times the pitch diameter, is larger than the dedendum circle you will find it necessary to undercut the root.
Said undercut weakens the tooth, is difficult to manufacture and reduces contact area.
In short, my guess is that your source is suggesting a "dedendum TO base circle relationship" on pinions with a small number of teeth.