Building my own Reciever Hitch

[spclays1]

I'm making my own reciever hitch out of stainless steel. Does anyone happen to know the metric size and thread pattern for the bolts to attach a reciever hitch. I'm using the same 4 holes that the factory hitch uses and they are two different sizes. Thanks, Mark.

[spclays1]

FYI 2- 8 x 1.25's and 2-14 x 1.5's 1 1/2" to 1 3/4" long will do it. When its finished I will post a pic.