The distance from the pitch circle out to the tip of the tooth. For full-depth standard teeth it equals one module, or one divided by diametral pitch, so the outside diameter is pitch diameter plus two addendums. Long and short addendum designs, made by profile shift, lengthen the pinion tooth and shorten the gear tooth to avoid undercut and balance sliding.
Pinion OD is oversize, so it's a long addendum design, check for profile shift on the print before you scrap it.
Also heard as
- addendum height
Do not mix it up with
- Dedendum: Dedendum is the depth below the pitch circle, usually 1.25 module so the mating tip clears the root.
Related terms
Dedendum
The depth of a tooth space below the pitch circle, slightly larger than the addendum to give tip clearance.
Module
The metric measure of gear tooth size: pitch diameter in millimeters divided by the number of teeth.
Profile shift
Moving the cutter in or out from the standard position, making teeth fatter or thinner without changing pitch.
Tip relief
A slight removal of material near the tooth tip so each tooth enters mesh smoothly under load.