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Old 11-02-2012, 07:26 AM   #20
Donkey Hotey
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Joined: Aug 2005
Location: 20 Mule Team Trail (Palmdale, Ca)
Oddometer: 10,351
Quote:
Originally Posted by Roadracer_Al View Post
If it's a rear, shaft drive hub, the thing is going to be 8", maybe 10" in diameter.... i.e. not a nice svelte front hub. At www.speedymetals.com, a 10" diameter, 7" long hunk of aluminum costs $326 plus shipping. And most of it is going into recycling.

And, there are the drive splines to consider... that's time on a wire EDM, or possibly a custom broach, or if you can find someone who still has one with a really big work envelope, a shaper. Two are expensive and one is uncommon.

My original suggestion might sound like a lot of work, but it's actually massively easier to drill the holes in the new flanges while they are flat on the table than trying to drill spoke holes in a one-piece hub.
It's a cush-drive hub. He's not making drive splines, it's just 5 or 6 holes for the drive pins to engage some rubber donuts.

As for billet cost, yeah, if you go straight to the metal shop and ask for a cut bar, it runs that much but, he's not in production and only needs a single remnant. Bar-end remnants that big are plentiful and $2/pound and under (I've got some similar sized blocks laying around here right now). As you said, most of it will end up in chips anyway. Metal places don't have many people who have equipment to chew up that volume of chips, who will waste their time looking for a remnant that big; they have to sell 'em cheap.

The flanges you suggest would still have to come from some hella-big pieces of material. None of my spoke wheels have anything close to flat flanges with straight pulls to the rim. In fact, every spoke hole is compound-angle drilled. No matter whether it was a custom hub or custom flanges, the spoke drilling job would still be a setup nightmare (on a Bridgeport) or become 5-axis parts.

After that nightmare ended, somebody would still have to machine the cast hub with no guarantees that it isn't going to be a porous mess, not suitable for welding. He wouldn't be getting away from expensive or time-consuming machining and--in fact--it would be multiple parts that would have to all carefully fit together (more time consuming to manufacture).

He's not going to do any of this because the hub would cost more than the whole motorcycle is worth but, I couldn't figure out where you came up with multiple pieces somehow being easier or less expensive.

Yours IS a novel approach and could get the job done but, in the end, it won't be cheaper or easier.
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