Thick walled vs solid

**Liftoff** · 30th November 2013, 16:37

Originally Posted by maddox10

Have some reading guys.

http://en.wikipedia.org/wiki/Neutral_axis

Tube is a lot stiffer/stronger weight for weight than solid.

Exactly my point...

**Garfie489** · 30th November 2013, 16:43

The actual material in a hollow tube is stronger than a solid one, because its likely to have had some form of additional cold work performed upon it, which increases strength, but reduces ductility.

**Liftoff** · 30th November 2013, 17:17

Size for size, ie if you want a 20mm dia by 100mm long shaft, a solid shaft will be the strongest option you can get. A hollow shaft of the same external dimensions will be weaker, depending on how much material is removed but weighs much less than the solid one.

Now lets say the 20x100mm solid shaft weighs 500g, for that same weight you could get, say a 30mm dia by 100mm long hollow shaft. Now the hollow shaft will be much stronger than the solid, even though they weigh the same.
I'm talking same materials here...obviously.

So in conclusion I'd say, if you're limited to a 20mm dia, but weight is not a problem, then go with a solid shaft as it is the strongest option you'll get.
On the other hand if weight is a problem, but diameter dimension can be increased, then use the largest diameter tube you can use.

**mattsdragons** · 30th December 2013, 13:48

Ordering parts today, after some opinions

Is it worth saying the extra for silver steel shafts or am I fine to just go with normal stainless steel ones?