Make Your Own Squat Rack
Step 6 - Attaching the chin-up bar (optional)

If you want to add a chin-up bar, it is easy.  You just use a saw (reciprocating worked better for me than circular) to cut a channel across the top of both 4x4's.  I started with a V groove and made it into a channel as wide as the metal pipe.
I then checked with a level, and cut one side a little deeper until the bar was perfectly level.

 

Steps

1. Dig the post holes
2. Mix the concrete and level the 4x4's
3. Bend the brackets
4. Attach the first bracket
5. Determine level and attach the second bracket
6. Cut grooves / channel for chin-up bar on top of each 4x4.
7. Bolt down chin-up bar
8. Support braces and weight holders (optional)

 

Materials and Equipment