Turn Buckle Threads
With all due respect, using a bolt instead of a clevis probably is not a great idea. Clevis pins are generally forged while bolts are not. In other words, a normal bolt of equal diameter has substantially less strength than a clevis. Also you need to worry about using excctly the right length bolt so that you do not end up with threads bearing on the jaws and so that the bolt is tight enough not to allow the jaws to spread.