Machining a Go Cart Wheel Hub

I'm working on a go cart as a school project with a friend. Our budget
is extremely limited, so we're leaning towards machining our own wheel
hubs. I have a HF minilathe, 1/2" drill press, and a 120v lincoln mig
with c25 and straight argon, so welding aluminum is possible. I'm
wondering what kind of accuracies would be required. Bolts will be at
a 4" circle, tire diameter of 6-8" at a speed of up to 25 mph, I'm
calculating 120 rpm (is that right?). Although this is kind of low,
I'm affraid the heavy radial loads may damage the bearings, especially
with no suspension. I'm confident I can hold 20 thou tolerances with
the setup I have now, but is there anything else I should consider?
I'm using the stock three jaw chuck, with HSS. I have a few boring
bars for the bearing. I don't have a rotary head or cross slide vise,
but have a wiggler.
An example can be found at
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Reply to
Jeremy Samuels
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Why not use the HF wheels? For example,
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?Itemnumber=30900 etc.
Reply to
Richard J Kinch
Go ahead and make the wheels. If they are too wobbly, paint the cart up and sell it to some circus clowns for a funny car. Seriously, with that little equipment and expertise, stick with stock wheels. Try haunting some wrecking yards for parts. Bugs
Reply to
Bugs
Forget about aluminum with the welder you have.
You'll want a lot better than 20 thou tolerance on a bearing housing. You should be able to hold 1 thou with your minilathe over a short distance like the depth of a bearing. Just take it slow, don't get in a hurry, measure often, take more than one pass at a given setting when boring because the bar (and the small lathe) will flex a little until it's only skinning a thou or less.
Reply to
Don Foreman
$20?!! Have you priced out what material costs will be to this yourself? I seriously doubt you can get to less than half, so is your time worth $10(per). And that assumes that you get it right the first time.
I realize you are a poor student, but for a potential $20 savings for probably at least a day of work, I could find other places to employ some "sweat equity". There is a pretty high chance of making some scrap or borderline acceptable part here.
JW
Reply to
jw
Here is Option B:
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JW
Reply to
jw
Jeez, give the kid a break! He has some tools, he probably has access to scrap material for free, and he has time! Note the "rec." in the newsgroup title. This is recreational, and doesn't need to be cost-justified. Sometimes we want to make things because we can, for the pleasure of doing so.
Reply to
Rex B
I totally understand that. Just asking him to think about what is going into this. He implied money was a big deal, sometimes making it yourself isn't the cheapest solution(even with "free" labor).
I'm all for making things, just because you can. Done it myself many times. But he's trying to make a go kart. Not screw around trying to make an adequate wheel hub to get it going.
There are a lot of other places on a go kart I would choose to spend that much effort DIYing than on machining hubs. IMHO.
JW
Reply to
jw
Jeremy -
you might want to check your math on the rotational speed required for an 8" wheel to go 25 mph.
Doesn't matter for the question at hand, but if you use 120 rpm as a target when you figure the gears or chain sprockets you'll be disappointed with the result...
Carla
Reply to
Carla Fong
Good catch. I thought that rpm seemed really low for 25mph. :)
JW
Reply to
jw
Here is some ODs for typical kart size tires.
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--Andy Asberry recommends NewsGuy--
Reply to
Andy Asberry

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