Finally, something to report. The bare frame to fill the door opening is in place and tacked together. It looks like this:
I realize that this doesn't look like much, but that's because you can't imagine how difficult it was to figure out the approach and get ready to do it. No — wait — most of you folks have done conversion work, so you do know how long some apparently simple things can take. Anyway, her is yours truly feeling smug about finally getting this bit of work into concrete form:
The problem was that this assembly needs to be removable. I have to remove it to finish it, I might need to remove it to get large furnishings into the bus (you never know), and if we're ever teeboned on the right side, being able to remove this assembly will make repair possible without starting from scratch. Keep in mind that I'm attaching a mild steel door frame to an aluminum body. Can't merely weld it in place.
The opening in the bus body had a type of tee nut slot on both sides and the top. Looks like this:
The opening in this slot is 13/16" wide. I put time into researching sources for tee nuts this wide. I finally found some that I thought would work on the McMaster Carr web site. Spent a considerable amount for 11 of the little beasties. The ones I ordered were actually for a 3/4" slot, but I figured they would be wide enough, and the 13/16" nuts were outrageously expensive. Besides, they required a 3/4" bolt. The ones I got use a 5/8" bolt, and I knew even that would be overkill.
When my tee nuts arrived, I was dismayed to find that they were too deep to fit my slots. They require 7/16" clearance, and my slots only provide 3/8". They are too hard to machine with a high speed mill (don't ask), and it would have taken many hours with a grinder to make them fit. Besides, they would still require 5/8" bolts, and I figured out that the size of the bolt heads would interfere with the rest of the structure.
The original door mechanism was held at the bottom of the slots with tempered aluminum nuts that look like the bottom one in this photo:
I figure they might be proprietary for Gillig. I could not find a source, and I had no tempered aluminum to work with. I did, however, have some 3/8" thick mild steel. I ended up making eleven nuts for the project. It involved much grinding, boring, tapping and finishing, but you know the drill. (Pun intended.) Here are a few shots of the process:
This is the way the first one looked on trial fit:
The next problem was challenging. I knew that I wanted to make the outer frame of 2x2x1/8" angle iron. I could have merely bolted these pieces to the sides and top of the opening with my new tee nuts and the 5/16" bolts that fit them. I could even have removed such an assembly. The problem would have been getting it back in place. Once the frame was welded together and the bolts were removed, it would be impossible to get the bolts back into the tee nuts. I suppose the nuts might have been glued in place for future removal of the assembly, but this did not seem like a good idea to me.
The solution I finally devised was to make brackets to secure a 3x1/8" base plate to the top and both sides. The angle could then be welded to these base places, and the brackets would allow the entire assembly to be unbolted without disturbing the tee nuts. The brackets look like this:
The additional layer of steel welded on the end is to compensate for the thickness of the heads of the bolts that hold the tee nuts in place. Here is a bracket bolted in place:
I put four of these on each side, and three on the top. Here is a base plate bolted in place:
Here is a shot of the framing clamped in place before welding:
You can see in the last photo that the bus sides have an angle that is not apparent until you place a long straight edge along the door opening. Time will tell if I am able to match the steel skin panel to this angled frame and the straight door jam. The jams are also made of 2x2x1/8" angle.
And that's how we got to the first photo in today's post. Here's a little number I picked up recently to aid the conversion and other areas of my life:
In case you can't tell, it's a drill press, milling machine and metal lathe combo. The lathe will turn a 14" circle, but I will have to add a separate cross slide to get anywhere close to that much clearance. It's Chinese, but still a pretty sweet tool.
To give you an idea of how busy I've been, this new Rheem demand water heater has been sitting in the bus unopened for more than two weeks. I got it out today so I could show you a pic. It will mount in the area above the engine where the air handler used to me. These are supposed to be terrific:
That's all for now. I believe I have all the steel to complete the door. I have to go out of town for a couple days, but hopefully more door pics are only a few days away. In the meanwhile, everyone be well and keep up the good work.