Ok, so where to get a slug that will be of decent enough quality to machine what I am envisioning?? My buddy Russ has a friend with a machine shop that has bins of drops (cutoffs) and said he was going down there to get something and he would check to see what he had that we might be able to use. He found an unmarked slug in a bin of 4140 and 4142 drops, so it should be one or the other which would machine easily, but have good strength. Well, it turns out to be something completely different. Russ found this out after beginning the machining process. The material coming off of the slug was like a coiled up razor blade and would not break!! After some investigation, he determined that it is annealed 4340 spring steel. Way overkill for what we need, but it's what we have. He managed to find a feed setting that would break the material coming off into about 4-5 inch pieces (he was getting 4-5 FOOT long pieces of razor blades coming off of it). The material composition did not lend itself well to a nice surface, but it isn't going to be seen, so I don't care. This is what we ended up with: (no pics of it being machined, but here is one of the bolt circle being drilled)
If you look closely at this pic, you can see the one dimension I gave him to start with (one inch):
The threads are 30mm 1.5 left hand threads. They turned out better than the ones on the stock hub. This pic shows the 1/4" hardened pins that Russ added for more insurance in alignment and strength:
Another angle:
We decided to go with the pulley for the long hub so the spacer could mount directly to the hub and have a nice shoulder for strength. Here is a test fit on the motor:
Looks sweet. Let's try the fan now:
It fits good with good clearance to the radiator (pic does not show this well) and 3/16-1/4" between the fan and the oil fill, water pump and crank pulley. Now for a shroud:
It fits good. Not quite half-in half-out, But I'm calling it good enough at this point. I did all of my test fitting with the stock viscous clutch because it is less cumbersome that the Horton that has a leash (Harness) that seems to always be in the way when working with it. The clearance between the clutch and the radiator is great enough that it will clear the Horton fine.
So there you have it. One bishin' piece of engineering to solve a strange problem. Many thanks go out to Russ for his perseverance and skill in turning an otherwise generic slug of metal into spiral razor blades and a hub that alleviates a major roadblock on my path. Thanks again!!