Our team was having trouble putting locking screws in without destroying our tools and were wondering what other people were using to put them in.
get better tools 
all the vex tools that came with the package got stripped right away
our mentor went to a local hardware store and got better quality ones and they never stripped once!
*i broke the “ball” off a key yesterday, but after we grinded it flat, it was as good as new
Easier said than done. We can’t get imperial tools very easily here in NZ unfortunately
actually, mitre 10 has imperial allen keys. Or you could go to an engineering place such as Waitemata Hydraulics & Engineering Supplies Ltd. http://www.waihyd.co.nz/
Or, ask your metal work teacher where your school gets its engineering supplies. If you order them through school, your school probably gets a discount
We uses hardened steel ones from the local hardware store. Personal mail me your address and I’ll toss a few of both sizes in the post since they are hard to get there. I have fond memories of my Kiwi mates from the two years I lived in Wellington. I’m happy to help out a country that knows what a proper meat pie is, makes 1000’s of well made Pavlovas every year and of course Black Mac’s.