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-   -   AndyMark 8 Inch pneumatic hub fail (http://www.chiefdelphi.com/forums/showthread.php?t=144346)

Fusion_Clint 21-02-2016 14:09

AndyMark 8 Inch pneumatic hub fail
 
All,

We took apart our drivetrain to give it some TLC today and discovered all of our 8 inch pneumatic hubs are failing. Very similar to the rhino tread pulleys.

If you are using them, I suggest you take a close look are your hubs.

I just sent pictures to AndyMark and we awaiting for a reply.

Locktite was just applied, it was not there before about an hour ago.

http://imgur.com/a/DX4OH


SamM 21-02-2016 14:13

Re: AndyMark 8 Inch pneumatic hub fail
 
Is that loctite on the nuts? Loctite will destroy the polycarbonate hubs.

sanddrag 21-02-2016 14:14

Re: AndyMark 8 Inch pneumatic hub fail
 
What's the blue stuff all over? Is that loctite? If so, that explains it. Loctite eats polycarbonate, chemically, causing it to become brittle and crack.

Cory 21-02-2016 14:15

Re: AndyMark 8 Inch pneumatic hub fail
 
They're failing because you put loctite on your screws.

You shouldn't have done that for 2 reasons, the first being that loctite will melt the plastic, the second being that it's pointless because you're using nylock nuts.

orangemoore 21-02-2016 14:27

Re: AndyMark 8 Inch pneumatic hub fail
 
Even have been using these hubs successfully without using any loctite.

It seems like this isn't Andymark's fault.

Fusion_Clint 21-02-2016 14:38

Re: AndyMark 8 Inch pneumatic hub fail
 
The locktight was just applied to get through the next couple of days!

The damage goes all the way through the hubs.

I highly suggest everyone using these take to a look at your hubs.

troy_dietz 21-02-2016 14:50

Re: AndyMark 8 Inch pneumatic hub fail
 
You don't need loctight when you use nylock nuts...
Looking at how much excess loctite is on the hub, that damage could have easily been done by a combination of chemical breakdown and stress on the plastic.

kevin.li.rit 21-02-2016 14:52

Re: AndyMark 8 Inch pneumatic hub fail
 
Quote:

Originally Posted by Fusion_Clint (Post 1543723)
The locktight was just applied to get through the next couple of days!

The damage goes all the way through the hubs.

I highly suggest everyone using these take to a look at your hubs.

Again, it looks like the failure was caused by the loctite and not the hubs. It causes the polycarbonate to get brittle and crack so I'm not surprised the damage goes through the hub.

Fusion_Clint 21-02-2016 14:53

Re: AndyMark 8 Inch pneumatic hub fail
 
Locktite was just applied, it was not there before about an hour ago. After the damage was found a student put the locktite on in an act of desperation.

MrBasse 21-02-2016 15:00

Re: AndyMark 8 Inch pneumatic hub fail
 
Quote:

Originally Posted by Fusion_Clint (Post 1543735)
Locktite was just applied, it was not there before about an hour ago. After the damage was found a student put the locktite on in an act of desperation.

What did you anticipate loctite helping with that the lock nuts weren't already doing for you?

billbo911 21-02-2016 15:27

Re: AndyMark 8 Inch pneumatic hub fail
 
Everyone, please read the thread BEFORE responding.
The Locktite was added AFTER the failure. It is NOT the cause of the failure.

I believe the nylock nuts may have actually contributed to the failures.
Some nylock nuts have larger outside dimentions than the comparable regular nuts.
Forcing the larger nut into the hex opening, and over tightening them may crack the polycarbonate.

JohnFogarty 21-02-2016 17:00

Re: AndyMark 8 Inch pneumatic hub fail
 
Quote:

Originally Posted by Fusion_Clint (Post 1543723)
The locktight was just applied to get through the next couple of days!

The damage goes all the way through the hubs.

I highly suggest everyone using these take to a look at your hubs.

What screws/nuts are you using?

I've got 3 robots I'm working with that are using those hubs and none show anything like that kind of wear.

Cory 21-02-2016 17:02

Re: AndyMark 8 Inch pneumatic hub fail
 
Quote:

Originally Posted by billbo911 (Post 1543754)
Everyone, please read the thread BEFORE responding.
The Locktite was added AFTER the failure. It is NOT the cause of the failure.

I believe the nylock nuts may have actually contributed to the failures.
Some nylock nuts have larger outside dimentions than the comparable regular nuts.
Forcing the larger nut into the hex opening, and over tightening them may crack the polycarbonate.

We did read the thread. He edited his original post to say that it was applied after the damage appeared.

[edit] On closer inspection there are some cracks around the nut cavities that look like they might be consistent with slightly too large of a nut.

Fusion_Clint 21-02-2016 17:08

Re: AndyMark 8 Inch pneumatic hub fail
 
Look, I'm not trying to get anything other than the word out to check your hubs.

The locktite was applied after the fact.

We are fixing our issue, just make sure you don't have the same one.

billbo911 21-02-2016 17:14

Re: AndyMark 8 Inch pneumatic hub fail
 
Quote:

Originally Posted by Cory (Post 1543795)
We did read the thread. He edited his original post to say that it was applied after the damage appeared.

I'm not saying OP is a liar, but that damage looks a lot like the damage loctite would create when applied to plastic. See this picture

No argument. Locktite WILL cause this type of failure!

Forcing in nuts that are too large for the opening can crack the polycarbonate too. Just my $.02.


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