You are going to want to make a mounting plate for that trailer jack. The long bolts and thin metal clamps will do nothing but bend once you have a lot of weight on it. Something like this:
Mine isn't pretty but it works very well. Hope that helps.
Everlast PowerTig 200DX
Everlast Supercut 50P
I need a MIG.... which one to buy:
I-Mig 160, I-Mig 200, or a MTS 160