Note: Earlier this morning, I hit "Post Reply" - accidentally - before I had completely written this post, so I quickly deleted it. For those of you who may have received notification of a new post that wasn't there, I apologize!
I didn't take time to post yesterday, so I'm starting today off with a post on yesterday's activity. Yesterday was one of those days in the shop where I "do a lot of stuff," but at the end of the day, only one checkbox gets checked. However, there was a lot of activity going back over three years to check that box, so it was very satisfying to finally be able to check it! Hang on, 'cuz I'm startin' at the beginning. It was a long process for me, and it's gonna be a long story for y'all to read!
The checkbox I checked yesterday was getting my diff covers completed. Sounds simple. So how did this become a three-year process? Well, I bought my LJ during COVID, and many of the parts were backordered for long periods. I had been reading this forum while looking for an LJ to purchase and putting a build plan together, starting in early 2021. The LJ was purchased in June 2021, and I started acquiring parts at that time. I had discovered the Barnett diff covers through the forum, and as
I reported in Mr. Blaine's long Barnett cover thread from that time period, it took four months to get a set of covers, and they were built on old, rusty covers because Dana stopped supplying new covers to T and J for a while. The guys at T and J gave me the option of waiting indefinitely for new covers, but I didn't care if they were used, so I accepted the used ones.
Anyway, I had the covers powder-coated and thought I was done. Then, after they sat on the floor for a good while, I decided to hard surface them - throwing more money out the window (my powder coater does fabulous work, but he's in high demand, and his prices reflect that.) It was my experience in the civil design/construction world since I left motorsports, along with a
post from Mr. Blaine in the same Barnett cover thread, that combined to put the hard surface idea in my head.
I knew that laying down a bunch of beads on stamped steel part was going to create a high potential for warping before I started. I set the welder up on the cold side of the settings spectrum, used a rosebud to preheat the cover, and welded and paused frequently to limit heat in the covers. Unfortunately, despite my best efforts, the covers warped enough that I wasn't confident I could get them to seal to the housing. So, I put them back on the floor for over a year since I didn't need them, yet.
During that year, I read up on flame straightening. Flame straightening is a black art used to straighten bent steel structures. There's even a manual put out by the Federal Highway Administration,
FHWA-HIF-23-003. I was aware of flame straightening due to my civil work these days, but I'd never seen it done. I decided to try it. I tried to use a cutting tip to concentrate the heat energy in areas where I wanted to bend the cover. What I learned was that you can't learn to flame straighten quickly. The guys that do it on large structures do it as apprentices for years before they are allowed to be in charge of the task. I don't have years to practice this, so I decided to try a different technique.
After those efforts failed, I bought a big slab of steel and drilled and tapped to bolt the covers down. Here's that slab:
After bolting the cover down, I used a rosebud to get the gap areas red hot and then used a clamp to try to push it flat and hold it there while very slowly cooling it (I piled on a big welding blanket and let it sit.) Those attempts were mostly futile. I started with gaps of 60 to 80 thousandths of an inch (about 1/16"), and I may have reduced them by 10 to 20 thousandths after my efforts. The problem I ran into was that I just couldn't get and keep enough of the cover red hot to use that technique. Again, the covers went back on the floor for months while I pondered my next move in the back of my mind while working on other stuff.
Regular readers of this build thread may recall the issue I had when I paid a local machinist to countersink my transfer case skid's mounting holes for flat head screws. The short version of the much longer story (that started with a tease at the
end of this post) is that I specified a 90° countersink angle, but ended up with 82° countersinks. My machinist owed me a favor from this screw-up, so earlier this week, I saw those diff covers on the floor and decided to drop them off with him to see if he could re-surface them for me. At the end of that same day, I got a call from his wife, who runs the office, saying that they were done, and there was no charge. Nice! I picked the covers up Friday.
And that brings the story up to yesterday morning. I needed to prep them for paint because the surface I was dealing with was a combination of rusting steel-in-the-white, burned powder-coating, and intact powder-coating. Prepping them took most of the morning. I used a coarse wire wheel on an angle grinder, a small wire wheel on a Dotco pencil grinder recommended in the New Tool Day thread by
@Mike_H (thanks for the tip - it's much better than my M12 rotary tool), followed by over an hour in the bead blaster. Then, I shot them with primer and top coat. Here they are finally done:
Wow. This post is a crazy long way to say, "yesterday, I painted my diff covers."
But those diff covers may never even see use on my LJ. I was able to find two of those high-fill-point, thick Dana covers on eBay a few months ago, and when I get to it, I plan to come up with an AR400 or AR500 skid plate design that will bolt to a Dana cover, similar to the skid on Currie's Dana 60 axle. I had SendCutSend make me a 1/2" thick collar that I can use to fixture the cover to that big slab during welding:
That skid design is just an idea for now, so stay tuned to see where it goes (hopefully not in the dumpster).