Chief Delphi - pic: Twisted Hex Shaft

Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Extra Discussion (http://www.chiefdelphi.com/forums/forumdisplay.php?f=68)

- - pic: Twisted Hex Shaft (http://www.chiefdelphi.com/forums/showthread.php?t=94011)

rahilm

25-03-2011 13:38

pic: Twisted Hex Shaft

loading photo ...

Racer26

25-03-2011 13:50

Re: pic: Twisted Hex Shaft

Impressive. A harsh reminder of the kind of force that FRC bots exert.

Jared Russell

25-03-2011 13:54

Re: pic: Twisted Hex Shaft

3/8" diameter, 2024 aluminum?

I'm curious to know just how much torque that took...

In 2008, our arm was able to rotate the keyway of a piece of hardened 1/2" steel keyshaft almost 90 degrees. It's impressive how an FRC robot can destroy itself!

Andrew Y.

25-03-2011 14:14

Re: pic: Twisted Hex Shaft

waht kind of aluminum is the turnbuckle?

rahilm

25-03-2011 16:25

Re: pic: Twisted Hex Shaft

Quote:

Originally Posted by Jared341 (Post 1045089)

1/2" 7075, which is why we were pretty surprised.

Quote:

Originally Posted by Andrew Y. (Post 1045095)

waht kind of aluminum is the turnbuckle?

Not sure the alloy, but it was some small diameter (bad idea in hindsight)

Andrew Y.

25-03-2011 16:31

Re: pic: Twisted Hex Shaft

gotcha 7075 was the number iw as looking for. Just to be nosey it wasnt 7075 -0 right?

Cory	25-03-2011 16:48

Re: pic: Twisted Hex Shaft

Quote:

Originally Posted by Andrew Y. (Post 1045116)

gotcha 7075 was the number iw as looking for. Just to be nosey it wasnt 7075 -0 right?

I've never seen Al hex in anything other than T6

Brandon Holley

25-03-2011 16:56

Re: pic: Twisted Hex Shaft

Wow, that is quite a failure for a 1/2" 7075 shaft. Can you explain in a bit more detail the application this was in under failure?

-Brando

Andrew Y.

25-03-2011 16:58

Re: pic: Twisted Hex Shaft

Quote:

Originally Posted by Cory (Post 1045119)

I've never seen Al hex in anything other than T6

never seen dosent mean never exists. :)

most common types of 7075 is 0, T6, and T631. Although there are MANY different types such as T7362 is also a common one.

rahilm

25-03-2011 17:07

Re: pic: Twisted Hex Shaft

Quote:

Originally Posted by Andrew Y. (Post 1045116)

gotcha 7075 was the number iw as looking for. Just to be nosey it wasnt 7075 -0 right?

T7351 Actually.

Quote:

Originally Posted by Brandon Holley (Post 1045123)

Wow, that is quite a failure for a 1/2" 7075 shaft. Can you explain in a bit more detail the application this was in under failure?

It was on our arm. Basically we have 2 Banebot's gearboxes with chain running up to the arm. We have approx. 50 lb-ft of torque (don't worry, 1:4 chain reduction, only 6.25 lb-ft on each gearbox). We have chain on either side of the arm, and we decided to change the tensioning method to turnbuckles. Almost immediately as we raised the arm, the turnbuckle one side (the twisted side failed) while the other one held. The torque of the arm in addition to tension being held by the chain all released in one instant twisting the shaft, as the tension still held on the other side (on which the gearbox's rollpins sheared)

Andrew Y.

25-03-2011 17:24

Re: pic: Twisted Hex Shaft

Quote:

Originally Posted by rahilm (Post 1045126)

T7351 Actually.

thanks for the assist...my brains all scrambled this morning

sometimestommy

27-03-2011 17:10

Re: pic: Twisted Hex Shaft

Whew! thought that was a lead screw

ligiahag7902

28-03-2011 04:57

Re: pic: Twisted Hex Shaft

Quote:

Originally Posted by sometimestommy (Post 1045864)

Whew! thought that was a lead screw

I also think so.

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