need input on another d44 sas please

[JohnnyU]

They claimed it was possibly a bad batch. The new shaft supposedly has undergone a different heat treatment process (never looked into what that process was) and is supposed to be stronger. The new shaft definitely looked different, and I haven't had a problem since. Lifetime warranty FTW.

Surface finish can play a HUGE role in the strength of a shaft; and as far as I could see, the finish on the first shaft left quite a bit to be desired.

 

[dangerranger83]

Lifetime Warrenty.....Damn. Get those shafts!!!!!

 

[Bray D]

Surface finish can play a HUGE role in the strength of a shaft; and as far as I could see, the finish on the first shaft left quite a bit to be desired.

The finish was definitely better on the replacement shaft.

Surface finish really matters that much? I'm modeling parts/detailing drawings for Excel. The surface finish is specified on every part we make, so I'm sure its important. Other than reducing the diameter due to a rough surface (coarse turning grooves), what are some other not-so-obvious effects? Working for these guys has taught me that I have a LOT to learn when it comes to materials haha.

Dangerranger - We'll see how 'lifetime' the lifetime warranty is. I have a feeling its a lifetime warranty for the first failure. Hopefully I'll never have to find out.

 

[JohnnyU]

The finish was definitely better on the replacement shaft.

Surface finish really matters that much? I'm modeling parts/detailing drawings for Excel. The surface finish is specified on every part we make, so I'm sure its important. Other than reducing the diameter due to a rough surface (coarse turning grooves), what are some other not-so-obvious effects? Working for these guys has taught me that I have a LOT to learn when it comes to materials haha.

Stress concentration.

For a shaft in torsion (that's their purpose after all) tool drag, as an example, will act like those cardboard tubes that Pillsbury Biscuits come in unraveling it and basically resulting in catastrophic failure. A ridge or any other nonuniform feature on the surface will almost always be your failure point. Eliminating those features results in a much stronger shaft.

Are these drawings for big yellow parts? Who does Excel cast for?

 

[Bray D]

Makes sense.

No yellow around here. We make aftermarket parts for rock crushers and mining equipment. Bunch of shafts, pins, gears, and bushings. A lot of material science goes into the design of our high wear replacement parts.

http://www.excelfoundry.com/replacement-parts