Your problem can be fixed by using a thermal drilled hole connection to hold the aluminum platform to the steel. It may also save you time and costs.
Check out this web site for more information:
www.frictiondrill.com
If it is the thread that is failing, I would also recommend using a roll form tap over a cutting tap. When a threaded hole is cold formed using a roll form type of tap, the material strength & properties are not removed by this operation. Cold forging or forming the threads make these types of...
Oh, forgot to mention that tool costs for friction drills is not $1600 by earlier post.
From my experience the drills run between $50 -$390 depending on size and type of application. And tool life is 3,000 to 40,000 holes depending on material.
Have you thought of using a friction drilled hole? It is great for blind applications. This process is used alot in Europe, but is just now beginning be understood in the U.S.
For more check out these sites:
www.frictiondrill.com
www.formdrill.com
www.flowdrill.nl
Using a friction drilled hole in the hydroform will solve this problem. No fastener needed. No more stripping.
You can read about the process at this site.
http://www.frictiondrill.com
Your situation might be a good application for a friction drilled hole. This process is great for blind holes and eliminating riv-nuts and other fasteners. Just a thought.
Check out these sites for the low down;
http://www.frictiondrill.com
http://www.flowdrill.nl
http://www.formdrill.com