Rounded off the Bolt on the Hydraulic Tensioner...

So... My dumba$$ rounded off the bolt that holds the tensioner, by using a socket wrench. The worst part is, is that I had a set of 12 pt box end wrenches in my drawer that I should have used but didn't.

The only solution I can think of is welding the box end wrench to the bolt but:

1. I don't have a welder
2. I don't have any welding experience

Can anyone here give me some pointers on welding a nut or wrench on to the bolt or any other way of getting this bolt off.

I did manage to get the inner bolt out by using a swivel socket and extension.

I attached a pic of the rounded bolt.

 

grind the head off then remove tensioner then remove the rest of the bolt

 

Thanks for the suggestion, but some of the guys on the Gen1 forum suggested I use a bolt extractor which worked great.