I purchased 1/2-13 carriage bolts 9" long at Home Depot. The rounded head goes against the wheel weight ( the square shank keeps it from turning ), then washer, lock washer and nut on the inside.
NOTE !!! The 9" length I mentioned works with my 10.50 fluid filled turfs and 8.50 turfs/ags rims using Gilson 65lb wheel weights.
Two are required for each wheel weight.