POP goes the corner bracket

[mooseman]

We recently re-meshed 10 frames , we are all Newman rollers (square bar) some of the older blue coated jobs (heavy) and some of the light weight MZX jobs. After a second stretch I set one of he screens behind me on the floor sitting on the square bar.
Went back to the next screen when I heard a POP. I said aw-geeze (or something like that) I popped a panel...damn.
Looked at the screen the mesh was OK??? on closer inspection I discovered one of the cast  the corner brackets gave up the ghost.
pics below......anyone else see this.
the frame in question is about 7 years old MZX square bar light weight jobbie , 196 mesh at @35  Nm.
mooseman

[Itsa Little CrOoked]

I didn't know they would do that!

Somebody else should have experienced that if it's a design flaw.

Is there an obvious "void" in the casting?

[alan802]

I've only used M3's and have stretched only a couple hundred and retensioned about the same number and I've never seen that.  Someone with more experience might have seen it before.  We've used frames from 25 years old to brand new.

[Printficient]

What tension?

[mooseman]

To be clear not throwing any dirt on Newman rollers, we bought this particular frame new, newmans are all we have. This is a cast part and not a real high quality casting FROM A SURFACE FINISH point of view.

Castings under high loads will fail and this one might have been on the lower end of the quality curve?
Also it may have had a hairline crack - fissure in it form some time or possibly just a cold shut from the day it was cast. Actually if you look at the edges of the cracks the grain structure of the metal is actually quite good
It just scared the crap out of me as I was not expecting it and very surprised to see it .
FYI we retention OFTEN... and have the torque wrench set at 45 Ft-lbs for the bolts which swim in never seize. Before someone chimes in to say the coated bolts do not need never seize we replace the standard short bolts with 1.5 inch bolts because the short bolts strip out of the lighter MZX ends ...they only catch a few threads
Anyway I am just wondering if this is an isolated issue .
mooseman

[GaryG]

It's them there Moosman forearms. 

Never seen that in 25 years.

[Zelko-4-EVA]

its happend to us on brand new frames - this pic was taken back in 2005  - i think they were UL style frames

[jsheridan]

Yes it happens now and then.
I've had a few break over the years myself.

[3Deep]

I must be a wussy I've never had that happen, now that I've seen it I'll have one to break in a few days lol.

darryl