Oh Snap!

[Cigalert]

I'm having a bit of an issue with a main ingredient to my production...a large spiral mixer has been acting like a cat. When it's moving it snaps and outside that it's been laying around not doing shit.

First off, 2 weeks ago the main shaft that turns the "hook" snapped. This is a 2' x 3" shaft....snapped. WTF...I've never seen anything like it. It's belt driven by 9 v-belts but I would think the belts would slip before this thing snaps. Either way, got a new way turned out of 304 and replaced all the bearings as a precaution.

2 days after the install 3 M20x55mm socket head bolts snapped. So this time, instead of the main drive shaft giving up the bolts that attach to it are the weak link. The bolts hogged out the holes pretty good so I laid, upside down re-tapping the blind holes in an attempt to save me half a day.

In the last week all 3 of the "hook" bolts snapped again. So I'm reading a little about these bolts. "They have a Class 5g6g thread fit, a minimum Rockwell hardness of C39, and minimum tensile strength of 174,000 psi. " 174k psi and these things are shearing like a fireball cap at riverland.

The bolts are seated properly, the threads are clean, the surfaces are faced....I'm running out of patience and if this shit goes down tonight I can kiss my next few days off cause I'll be pulling a 30 hour shift trying to get holiday orders out for tomorrow.

Below is a pic of the hook. 3 bolts install at the top of the hook into the shaft.

If someone can tell me how dough can snap 3 M20 bolts without throwing a 6' pry bar inside while It's running gets to be the first subscriber of my "loaves for life" repayment program.