Ring Gear Bolts

[JRas]

this is what I need:
http://img510.imageshack.us/img510/4167/82185820bq2.jpg

I got the wrong bolts mine are straight 13mm shank and 13mm thread size, my question is can I get the threads downsized to 12mm?

[JRas]

going to a machinist today he said it may be possible depending on thread pitch size and some other variables

hopefully... it works out