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heads up...dmm dragon #5


RuMR

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Did they come from the factory like that or did the cracks develop after some use? The first is QC the second is possibly an R&D issue for such new cams.

 

"I’d like to alert you of a problem we found today with DMM Dragon Cams. Several DMM Dragon Cam #5 in our inventory have cracks in the aluminum axle boss. These are cracks radiating from where the stem lug is pressed into the aluminum and are visible from the top of the cam as well as the underside."

Edited by KirkW
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DMM has a full recall on the 4s and 5s now.

 

Welcome to DMM

Important Safety Notice: Dragon size 4 and 5 Recall

 

For the safety of all of our customers we are issuing an immediate recall for all Dragon Cams size 4 and 5 with turned axle bosses

 

More information available here.

 

http://www.dmmclimbing.com/dragonrecall45.asp?l=en

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If it was stress corrosion cracking (SCC), they may not have cracked before they left the factory. But the constant tension from the press-fit could have caused a crack to develop after some time and exposure to a corrosive environment. Certain alloys and tempers of aluminum are more susceptible to SCC than others. 7075-T6 is bad, T7 is better, 7050-t7451 is bomber. For a good read, search for NASA Stress Corrosion Cracking.

Edited by dennyt
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