Okie doke -- there are a couple of "issues" --
There are ALWAYS at least a couple of issues!
The first... You remember this? The super cool factory dust shield... Turns out that it needs a tiny bit more space beyond the relief I already gave it. When snugging the bearings, there was zero room between sloppy and locked. Once I removed the dust shield, the bearings can be snugged per the manual. So, that means that dust shield drags a bit.. man, it must be super close to fitting!
The plan for this is to slightly relieve the dust shield itself, then relieve the flange on the backs of the hubs a bit more... Not worried, it's past the bearing, so its not load bearing, and I only need 10 thousandths or so more room!
The second issue is that one of the two hubs has about 5 thousandths runout at the outer edge of the face. If my memory is moderately correct, I think Esteban said it should be closer to one or two thousandths. Not too difficult, chuck it up in the four-jaw, square it up and clean up the face and cut that relief. The big challenge is getting the hub squared up and concentric in the lathe. It has six faces so it would fit a three jaw chuck well, but those aren't adjustable to fine tune it to concentric. That's what the four jaw is for... But six sides on the hub vs a 4 jaw chuck means it's grabbing on two smooth surfaces and two lumpy, tapered surfaces. I fought and fought, but could not get it a close as I needed. I mean, I knocked that thing about forever and just could not get it into spec in all directions. Ugh!
So, plan B, turn it between centers. This is well known to be the best way to precision turn... So, all I need is an arbor!
I ran... well drove... down to the metal reseller and grabbed two feet of 2.375" diameter mild steel.. I really only need 8", but that 25 pound chunk was in their scrap pile so it's a bit cheaper per pound
(and it leaves me enough material to try again if I screw it up). On the four jaw, I turned one end down to 2" diameter to fit in my largest lathe dog
(or should I saw lathe dawg?), then center drilled both ends. Here it is on centers, ready to work!
First, I turned it down the full length to the shoulder to match the ID of the inner bearing (I measured the spindle diameters), then turned the first half down to the ID of the outer bearing. Once the bearings slide on (snugly of course), we're ready to go!
So the hub will sit on it just like the axle shaft, so any work I do on it will be perfectly concentric with the bearing races and axle shaft! Hopefully the runout will be down in the ten-thousandths range! I still need to make a clamp to press the bearings tightly to the hub. I'm not going to mess with threading it. Rather, I plan to make a split-collar that I can slide on the clamp down to hold it in place.
Here's the new arbor wearing it's dawg
And the arbor undressed!
I'll label and keep this arbor around in case I ever decide to do another patrol front disk conversion! It will make it way easier!
Once the color is ready, I'll assemble it on the arbor and turn the relief on the back -- I should have made the shoulder a bit wider -- maybe a half inch or so to make it easier to get tooling into it... too late now!
Obviously the last challenge is that the hub won't spin with the lathe since it will have bearings between the arbor and hub. There are two small threaded holes in the face. I plan to put a long screw into it so it will leverage against the dog itself for the drive. But this won't work when working on the back, so the bearing retaining collar will have a threaded hole that I will leave a long bolt in, then leave a long bolt in one of the hub hole to work as the drive.
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