Re: AndyMark 3/8-16 x 7 Hex Head Bolt bending
 

To help in identifying ANSI Graded Bolts. Grade 2 will have no markings on the head other than possibly manufactures code. Grade 5 bolts will have 3 tic/line marks on the head. Grade 8 bolts will have 6 tic/line marks on the head of the bolt.

Re: AndyMark 3/8-16 x 7 Hex Head Bolt bending
 

I suggest you go to Grade 8 Bolts. Please go to this web site: http://www.boltdepot.com/fastener-in...ade-Chart.aspx The Grade of a fastener is marked on the head. If you have no marks it is a grade #2, If 3 marks you have a grade 5, if you have 5 marks it is a grade 8. Grade 8 is a higher strength fastener. Here is an on line calulator : http://www.engineersedge.com/beam_be...m_bending2.htm
This is a simply supported beam with the load at the center. In your case the beam size is 3/8" dia. with the properties of the bolt head markings in the above web site from Bolt Depot.

My team also bent a grade #2 Bolt crossing the 4x6 bump. We replaced it with Grade #8. No problems since. It is not the Andy Mark Bolt it is the application and using the correct strength fastener for the job,

Norman Collier

Re: AndyMark 3/8-16 x 7 Hex Head Bolt bending
 

The kit frame axle bolts have always been a problem. On past teams that I mentored that used the kit frame, we always swapped out the kit bolts for a real grade 8 bolt. Beware that there is a problem with counterfeit bolts all over. Buy from a reputable supplier. Mcmaster would be one. In 2006 the drivers liked to get up on the platform and give the robot full throttle to launch the robot in the air. I tried to discourage this, but the bolts and frame took it.