Then I scribed some lines from the center to the rear corners. And then from the corners to the holes.
 

I'm using some 3/8" bar stock (right side) that is about 16" long. I drilled a 3/16" hole in each end that matches the holes I drilled earlier in the rectangle pieces. Then I drilled a 1/8" hole that goes into the 3/16" hole but doesn't go through either piece.
 

When I slide the two pieces together, you can see the dowel pin visible through the smaller holes. I'll be welding those holes shut and when that happens, the two pieces will become one. This are also known as Plug welds or Rosette welds.
 

After it cooled down, I used a file to clean up the welded area. Now I didn't weld both ends here, only one because I'll need to slide the 3/8" bar through the two pieces of chain first. Then I'll come back and weld the other end.
 

What I plan on doing is using some gun bluing on the steel pieces. However, I've never used cold bluing before but I've seen the results and think it will look good when finished. This kit came with three liquids but I'll only be using two of them. The third one assumes that you'll be removing the old gun bluing from your firearm but I'm working with bare steel so I won't need it.
 

I setup a small work bench outside, and it was a perfect day for this. The instructions say to use the cleaner first, rinse with water, dry it and then repeat this step a second time. Then you apply the bluing agent with the supplied swab. However, the length of time the bluing chemical is to stay on your work piece is between 30 seconds to a maximum of one minute. Then rinse your work piece to neutralize the chemical. I had my garden hose hanging just out of sight which made it easy for me to get at.

I did half of my work arrow (both sides) and then rinsed it to make sure I didn't exceed the max amount of time. Side note: The instructions say the longer that you leave the bluing chemical on, the darker it gets before rinsing it with water.

I counted in my head and never exceeded 45 seconds. By the way, the moment that you touch the round swab with the bluing chemical to the metal surface, it turns blue instantly. At that point it's like using a paint brush (a round one) but it's very similar.