The measurements are basically laid out, so I'll spend more time on the actually building of this ladder. The ladder itself is made from 1 1/2" I.D. schedule 40 pipe. The rungs are 3/4" round. This particular drawing shows the ladder fastened to a platform made of 6" channel iron with 1 1/4" bar grate on the top.

     Starting at the top, you will notice that the two short rails are 40" high, but not from the grate surface as is standard. Adding in for the two mitered sections, the top of the rails will actually top out a few inches above the hand railing that would be installed around the platform. This is done to make it easier to join the handrail to the ladder, as well as leave a short post to grab onto above the hand rail itself. When these two pieces are cut, cut them square on both ends at 40" and cut the angle after. This applies to the two longer side rails as well.

     The two mitered cuts are cut at 67.5° at a finished length of 5 7/8". To achieve this you will have to cut the pipe a few inches longer than the finished pipe, unlike the rails of the ladder. Use a pipe that is two or three feet long when working with short pieces like this and cut them off of the end. You will find it much easier to work with, as it will give you something to clamp in the vise while you cut the short pipes.

     To arrive at the measurements for the two longer side rails, measure from the top of the grate to the floor or level where the ladder will start. Cut the two sides to that length. The holes for the rungs are laid out at 12" centers from the top of the grate downward, with the first rung installed at 12". Each side pipe will have holes drilled on the inside only, that is, the rungs will not pass entirely through the rails, but will be stopped by the outside of the rail.

     The rungs are cut to a length of 19 3/8" and placed into the holes (drilled 13/16"). When the rungs are all placed, clamp the ladder together and the result will be ladder rungs that are 16" inside to inside. If you change the pipe size, the distance will change. Since the two rails are still cut square on the ends, simply place a square across the two ends and adjust accordingly. When that has been completed, tack weld the rungs in place, using a 6011 rod with high heat. The high heat will cause the tack to be flatter, which in turn will allow the final weld to be applied easier. To do the final welding, turn the ladder on its side and weld completely around each rung on all of that side, then turn the ladder over onto the other side and weld that side. You can now cut the angles on each rail. Next weld the 40" pipe and the small mitered pipe together. Grind the welds and you are ready to weld that assembly to the main ladder. To line up everything parallel, layout a straight line that is the overall length of the ladder. Lay the ladder along the layout line, and use a tape measure to line up the top section parallel with that line. Weld everything together to complete the actual ladder.

     Detail #1 shows the side view of the ladder and how it is secured to the platform. The end of the channel iron platform is shown in red for ease of viewing. The side of the channel platform is shown in black. To fasten the ladder to the platform, cut two plates 1/4" or 3/8" thick and notch them in the shape as shown. The length is 7" plus the depth of the channel. The distance of 7" is to allow for the foot to have clearance away from the platform when placed on the rung below.    The height of the two plates can be around four inches for use on a 6" channel. Note that the top edge of the clip is even with the top of the platform, not the grate. This allows for a section of grate to match up evenly with the main grate of the platform.

     To fasten the ladder to the floor, weld two angle iron clips, 2" x 2" x 1/4" cut  2" long to the backside of the ladder rails on the bottom. Have these clips drilled with a 5/8" hole in the bottom side of each one. From there it is a matter of drilling a hole in the cement to accept a bolt suitable to fasten the ladder to the cement, and tightening everything down.

   If the ladder is being placed on a metal surface, it can be either bolted or welded in place. I usually fasten the ladder to the platform at the top first with a strong tack weld on each clip. When it is to be fastened to the floor, the ladder will spring enough to allow it to be leveled and bolted down. It can then be welded solid at the top.