What type of steel are gears commonly made from?

[Matt Adams]

Originally Posted by Andrew

You also need to make sure you mean "yield" and not "ultimate." At yield, the tooth will deform. At ultimate, the tooth will break.

Not knowing what you are trying to accomplish, I would recommend using 30 ksi for yield and a safety factor of 2. If your numbers say this isn't going to be good enough, I'd start to look deeper into the type of material and actual loading conditions.

Just a couple of thoughts: In gears... I'd imagine that teeth deforming or bending aren't significantly better than breaking, since you'll obviously have pretty terrible binding issues with bent teeth.

The equations I'm using are the already conservative Lewis Bending equation, which assumes forces are acting at the tip, the length is the full depth, and the size is the width and height of the pitch diameter, treating it as a simple cantilever beam.

I'm trying to be conservative, since there will already be some dynamic forces involved as these gears will be engaging in the plane of rotation... but when you start compounding conservative values.. it gets to be a little crazy. I'm looking for something reasonably conservative. How you define that.. I don't know.

I appreciate your advice. Anyone else have thoughts?

Matt