Found hitch ball to work @ TSC. 2 5/16 with a 3/4" bolt.
www.tractorsupply.com/wcsstore/ConsumerDirectStorefrontAssetStore/images/products/600/0189993.jpg
Tractor Supply Company - 2 in x 3/4 in x 2 5/16 in Trailer Hitch Ball
www.tractorsupply.com/wcsstore/ConsumerDirectStorefrontAssetStore/images/products/600/0189993.jpg
Tractor Supply Company - 2 in x 3/4 in x 2 5/16 in Trailer Hitch Ball