On top of each of the front rails, measure back 1” from the front. Now measure from the angle cut at the back of the rail to the 1” mark. This dimension must be the dame on both rails. If it’s not, adjust the longer one to the length of the shorter one.
Now bring the 1” line over the edge of the tube to the inside of the tube (seam side). Mark and center punch 1” down from the top of the tube. This is the center for your front crossmember. Drill a 2” hole here.
On the outside of the rail, bring the 1” line down the tube. Now measure down 1” from the top. Use this point to scribe a 2” circle. Now trim the top, bottom, and outside of each rail.
Now for the front crossmember. Cut the 2” tube 22-7/8” long and set it aside. The last thing you need to do before assembling your frame is to fabricate the spring perches and their gussets. These pieces are made from ¼” stock. When you cut the 2” hole in the gussets, a little oversize is OK, this will make it easier to square them to the front crossmember. See drawing.