First off, I started with making a tool to seat the end of the bar stock I was going to be rolling. I picked up a 3/4" pipe nipple, since I estimated it to be the correct size needed to give the sleeve a 1" ID. If you intend to play along at home, please be aware that you will need a different diameter pipe to achieve that result.
I ground flats on opposite sides of the pipe, then set a point that was vaguely middleish on one of the newly planed faces. This was to mark where the slot was to be cut for my bar stock to seat.
Using a cutoff disc on the die grinder, I carefully ground out a slot that was intended to be uniform and thin enough to only allow the bar stock a snug fit as it passed through. I took my time and periodically tested with a square, deburred end of the bar, and immediately stopped grinding as soon as the needed fit was achieved. With the slot ground out of one of the pipe's flat sides, I drilled to holes clear through the pipe at opposite sides of the slot. The finished result looks like this:
Also needed is piece of angle iron that's several inches longer than the pipe. Set the pipe in the angle iron with the holes centered on the bend in the angle, then drill corresponding holes in the angle iron. This should allow you to bolt the pipe down into the angle recess. I'll have a picture of the assembly further down.
Having finished making my rolling tool, I determined how long a piece of flat bar would be needed by using these dimensions:
- Bushing OD: 1"
- Bar stock (thickness): 1/8"
- Desired sleeve OD: 1-1/4"
(bushing OD + (bar thickness x 2) = an expected ID that will fit the bushing. It won't. More on that later.)
- Mounting tab: arbitrary. Enough to have excess when fitting to underside of vehicle.
- Brake tab: variable. Dependent on squareness of end, how even surface is of bar.
A sleeve with a 1-1/4" OD has a circumference equal to just under 4", so rounding up, I knew I needed at least that much, plus some extra to grab hold of, and a little more to put bolts through when I was done. This is the end result:
Since the grabbing end was variable length, I wasn't able to mark out my 4" length until I set the end of my bar in the pipe and marked exactly where it met the pipe surface. The extra metal up to that mark is my grabbing end (referred to from here as "brake tab") and is sacrificial. It will be broken off once the metal is rolled enough to allow it to be finished into a properly dimensioned sleeve. Here is the stock seated in the tool:
After making the first mark, the additional lengths were added as shown above. The 4" for the sleeve was marked incrementally, since I would be scoring the stock at those points to create relief channels to make the bending easier.
The next picture shows the bar stock in the tool, then chucked into the vise so that I could begin cold bending it.
Once I reached end of travel as shown, I released the vise, then rotated the tool towards me before clamping it back down, like so:
Tightening the vise can allow you to do a fair amount of the bending without much extra effort. This process was repeated until it was no longer practical to keep trying to roll it this way, at which point the assembly was bolted to the angle iron.
From here, you pretty much do the same as with the vise, except instead of tightening vise jaws, you steadily and evenly tighten each bolt until you've reached end of travel. Unbolt, rotate, and repeat until it's not practical to do anymore.
This is about where I was once the point of being impractical was reached. From there, I chucked the assembly into a vise and used a MAPP torch to heat the bar where it began drifting away from the pipe surface. Once the metal was solidly orange in that area, I clamped some vise grips on the free end of the stock and continued curling it.
It's worth noting at this point that the section that will serve as the mounting tab is probably significantly arched. Don't worry about it. That will be flattened out when the final shaping is done.
Curl, heat, bend, etc until you have nearly curled the bar around enough to contact itself. There should be a gap around 1/4" or so. You'll be able to see that the relief cut made for the bending tab is showing signs that the metal is fatigued from being worked, and will break soon.
It appears that my phone didn't want to save the picture of what the stock looks like at this point, but it will more or less look like a numeral '6'. If it looks like a '9', throw it away and start over, or turn it upside down.
From here, you're just going to be closing the gap. Use whatever tools you have available to compress the roughly circle shape into a less roughly circle shape. What you're shooting for is the newly created end that the brake tab broke off from to meet the surface of the bar stock. You want the contact point to be as close to the final mark of the 4" length as possible.
It doesn't matter at this point if it's out of round (it will be). Once that gap is closed, drop a couple tack welds to keep it in place before uncompressing it. Make sure that these are solid tacks, or they'll pop once things are loose.
At this point, you may be thinking that the ID of this proto-sleeve looks a fair bit bigger than 1". That's because it was. I saw early on with with first sleeve that the 3/4" ID pipe nipple wasn't going to give me the results I was after. I rummaged around in Eagle and found a set of shackle bushings for an IH Scout that were large enough to eyeball that they'd fit, so I used those instead.
Now that you have your general shape secured, run a bead down the crevice where the outside surface of the sleeve and the mounting tab meet (or kinda meet, if that's the case, but NOT in the ID of the sleeve, or you're going to be doing a lot of grinding to get the bushings to fit).
With the piece welded together, you can start shaping it. Start by flattening out the mounting tab. This will help round the sleeve out. With the mounting tab flattened out, start hammering or compressing the high points of the sleeve. Use heat if needed. Get it round enough that you have a snug fit for your bushings. This isn't a tight tolerance part. It doesn't have to be pretty. When it reaches the point of clearly functional, you're good to go.
I missed the mark a little with the second piece while I was closing the gap, which left me with a corner edge on the interior surface that interfered with the bushing clearance.
No big deal. I just used a carbide burr in the die grinder to give it the old "port & polish". Here's the resulting pair of hanger sleeve bracket things:
No bolt holes in the mounting tabs yet, since I need to check under the vehicle for best placement. I'll follow up with how I'm making the hanger arms here in a bit.
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