I just found the cheapest 3/8" lag screws I've seen online, without buying a box of 50. Just over $1 for 14 inch ones. While I'd love the 18" ones that FIGJAM mentions, 14 seems to be good enough so far. http://www.thefastenerstop.com/product/FS215528.html FYI: These say "zinc," so they may just be ...