I'm trying to fasten some sort of pull up apparatus to the posts of our barn. I was either thinking getting some sort of pole and fastening across the posts or else nailing across a wooden 2x4. I'm thinking about going with the 2x4. Eventually I'd like to build up to be able to do muscle ups. I think the 2x4 would work better to push up on than a bar. I also think the 2x4 would be easy to fasten than some sort of a pole. I'd sand it down and round the edges off before putting it up. I was in Tae Kwon Do for years and our pull up apparatus was just a wooden rafter and it worked fine.