How to build a pull-up bar?

[SPP]

I want to add a pull up bar on my sloping block of land. I bought a spirit level and I can see that the land level is not perfectly straight (which is fine). 

Now, I want to install some steel posts. I was going to go for these: 

https://www.bunnings.com.au/australian-handyman-supplies-steel-fence-post-50-x-50mm-x-2-1m-galvanise... 

However, I am looking for one that is 3 m. Can you please like me to such posts. 

Also, what sort of bracket should I use to secure the rod into. My initial thoughts was something like this: 
https://www.bunnings.com.au/brasshards-galvanised-round-flange-with-25mm-drill-mall_p0178234 

Am I on the right track here? Any other thoughts/suggestions? 

[MitchellMc]

Hi @SPP,

I think you'll find that the 50mm box section will flex too much for your application. You'd be much better off with an Australian Handyman Supplies 89 x 89mm x 2.4m Galvanised Steel Fence Post. Even then, the Brasshards Galvanised Round Flange With 25mm Drill Mall at 96mm diameter wouldn't be able to mount on the post as it's too wide. You'd likely need to Special Order 100 x 100 x 3.0 posts directly from Australian Handyman Supplies through your local Bunnings store's Special Orders desk. Depending on the type of workout you are intending it would be best to have at least 800mm of the posts in the ground for anything that involves swinging. 

Please let me know if you have any questions.

Mitchell