I put a shock ease on a Hawthorne for my build off bike last year, it looks really good IMO.You have nailed all the issues down B808, and have great suggestions, some of which I will follow up with. But the low-mile, original paint frame MUST run a 1" steer tube fork: a 1-1/8 fork will NOT slide through the frame.......
Because we Ratters can be stubborn, I will still try to use the Shelby fork, as I can't envision the Monarch-style springer on the Hawthorn frame.. (which was considered for sure). If it tweaks the fork, so be it, and I will swap it out for the Monarch style springer..
The 20's Hawthorn Flyer frame has a very short "sleeved" head tube, and will ONLY accept a 25.4mm steer tube(1"). Though not a typical mod, I will experiment in true "Rat" form, and attempt to mate the Shelby Shock Ease springer with the Hawthorne straight-bar frame, while adding(welding) disc brake caliper post-type mounts to the left leg of the old springer. Sooooo....in order to follow up and complete my Ratty vision, I have been looking for a women's single pivot springer with a very long steer tube so I can cut it down to fit all the headset mods. These forks are "trussed", or fairly well reinforced and designed to take fore-and-aft forces, and hopefully enough strength so that a disc brake caliper can be mounted on the leg. Since the bike will not be pushed very hard in heavy braking situations,(mostly) I hope I can pull it off without putting myself in too much danger of the disc brake overwhelming(twisting) the old springer legs. I wouldn't normally put a disc brake on a 50's springer, but I am going for it regardless. Must be the rebel ratter in me..
I have an NOS 1" Tange G-master headset with roller bearings (threaded) that I want to fit to the frame. Since the frame is so old, the id of the frames' head tube/headset interface is a weird size, somewhere between a 1' and 1-3/16". The Tange 1" headset is smaller than the head-tube of the frame, so I picked up some headset to frame adapters (1" to 1-1/4") which need to be turned down to exactly fit the 20's frame. Then I can fit the Tange headset into that and use the 1" threaded Shelby fork. I will probably contact CM to help with turning down the adapters to exactly fit the head tube size. Once the fork is fitted into the frame, and the top threaded cup is installed, I will fit the upper truss rod support bracket and headset securing nut. At this point, I can determine how much steer tube I need to clamp the threadless stem to then cut to fit. And then the upper truss rods can be measured, cut, re-threaded and installed.
I considered the quill-to-threadless adapter, but it seemed like overkill, and since the steer tube on the fork is good heavy-gauge steel, I decided to go with an aluminum sleeve that fits over the threads, then clamp the 1-1/8" threadless stem(with sleeve) onto it for a clean look. Clamping the stem with sleeve to a threaded steer tube is a risk for sure, as the threads weaken the fork steer tube where the stem clamps on to, but I am willing to try it. It does make me a bit nervous, as the quill adapter is clearly stronger, so I may go that direction...
This is something I have wanted to do now for some time, so I will give it a go and post the results here in a build thread.
As we know, with old frames and forks, it can be a real challenge getting BB, headset and drivetrain mods to fit. I am a total cool-parts junkie, and love hanging high-end parts on old frames.... It's a Rat thing, and I really like discussions like this, where all options can be let out and vetted!!
Then I dragged the thing around the country, and rode on alot of varying terrain.
In my experience with the shock ease, I don't think adding disc brakes will be a problem for the fork to handle. As you said, you won't be doing any uber heavy riding or braking.
I'm curious to see how it works out.
And I agree about this type of thread, I've learned alot and gotten some good ideas. Now I'm just about ready to build my bike.