Author Topic: I made a bicycle hub  (Read 5342 times)

Russ

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I made a bicycle hub
« on: June 28, 2013, 06:50:00 PM »
Pretty self-explanatory. Funemployment while I wait to graduate has led to a couple fun projects over the summer, this being the main focus until now. Hopefully I will finish a rear to match sometime in the next month or so. Pics attached.






« Last Edit: June 28, 2013, 07:06:19 PM by Russ »

Russ

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Re: I made a bicycle hub
« Reply #1 on: June 28, 2013, 06:52:06 PM »
More photos






« Last Edit: June 28, 2013, 07:06:41 PM by Russ »

George_PA

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Re: I made a bicycle hub
« Reply #2 on: June 28, 2013, 07:33:03 PM »
You do nice work.  One thing that is on my mind however is why spend all that effort to replicate a part that can obtained easily. 

For example, the world has thousands of old/used bicycles readily available from places like craigslist cheap; If want two of these parts, you could just take apart an old cheap bike and get them.  Usual if I ever resort to make a customize part out of metal, it is for something that is usually shaped or rare or near impossible to find.

Forgive me if I don't know any better but is this supposed to be a super light-weight version used for racing or something along those lines?

kendallf

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Re: I made a bicycle hub
« Reply #3 on: June 28, 2013, 07:34:47 PM »
Very nice!  Did you do this on a manual lathe and mill, or CNC?  I love machining and took a bunch of classes when our local junior college still had a shop. 

Kriegsspiel

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Re: I made a bicycle hub
« Reply #4 on: June 28, 2013, 07:56:12 PM »
You do nice work.  One thing that is on my mind however is why spend all that effort to replicate a part that can obtained easily. 

For example, the world has thousands of old/used bicycles readily available from places like craigslist cheap; If want two of these parts, you could just take apart an old cheap bike and get them.  Usual if I ever resort to make a customize part out of metal, it is for something that is usually shaped or rare or near impossible to find.

Forgive me if I don't know any better but is this supposed to be a super light-weight version used for racing or something along those lines?

FOR THE LULZ.

I was gonna ask the same as kendalf.  Does OSU have a machine shop?

Russ

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Re: I made a bicycle hub
« Reply #5 on: June 28, 2013, 08:06:23 PM »
You do nice work.  One thing that is on my mind however is why spend all that effort to replicate a part that can obtained easily. 

For example, the world has thousands of old/used bicycles readily available from places like craigslist cheap; If want two of these parts, you could just take apart an old cheap bike and get them.  Usual if I ever resort to make a customize part out of metal, it is for something that is usually shaped or rare or near impossible to find.

Forgive me if I don't know any better but is this supposed to be a super light-weight version used for racing or something along those lines?

Of course I should have expected these questions from MMMForums :)

I made the hub for a few reasons:
-Advance my skills as an engineer and machinist. This project pushed the boundaries of my capabilities and I learned a lot.
-To have something I can show prospective employers to say "hey look what I can do". I'd like to work in product design, so having something I designed and prototyped myself from the ground up is valuable for interviews.
-THE LULZ. Machining is one of my favorite hobbies.
-Yeah, it's also quite lightweight. Not the lightest but pretty damn good. Similar quality hubs run around $150 - $200 new.

Very nice!  Did you do this on a manual lathe and mill, or CNC?  I love machining and took a bunch of classes when our local junior college still had a shop. 
manual. lathe mostly; the only mill work was drilling the spoke holes with a rotary table.

Does OSU have a machine shop?

Several! I worked in my department's student shop up through May. They still let me use the machines even though I'm not taking classes right now, which is very nice.
« Last Edit: June 28, 2013, 10:50:32 PM by Russ »

amha

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Re: I made a bicycle hub
« Reply #6 on: June 28, 2013, 11:15:42 PM »
This is awesome!!!!

Can you tell us more about how you made it? In particular, what's that little notch at the end of the pieces that the axle screws into (the one that goes around the circumference)? Are you actually going to build it up into a wheel? I've never seen a hub with sealed bearings before---is that a thing? (will the lack of adjustability cause problems?)

Sorry if these are too many questions---this is just so, so awesome. (My overly-anal safety-obsessed boss at the bike shop I used to work out would freak out if he knew someone was milling their own hubs without doing years of safety/stress testing...)

You should really post something about this on a real blog somewhere---you've inspired me to Google DIY bike hubs, but all I can find is this guy's one YouTube video: http://www.youtube.com/watch?v=A98ko6owHB8

Russ

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Re: I made a bicycle hub
« Reply #7 on: June 29, 2013, 09:41:49 AM »
Well... as to how I made it, most of the work was really design stuff. First, about 2 weeks of research. I would estimate I have about 50 hours just in reading and watching videos about bike and motorcycle wheels and hubs, including patent searches, finding photos of cutaways usually shown at trade shows, and watching videos from the guy whose link you posted. If you go through the video description there's a link to a much more detailed video of how he made a different hub shell, which was very cool to see. Unfortunately, he only shows how the shell was made, so we don't get any detail on his axle design.

Once you have a good idea on how things are done, try and come up with a way to make it better. What I did, which you can see a little in the attached drawing on this post, was avoid a traditional axle, instead having the bearings rest on the end caps with the compression tube in the middle providing no support besides positioning the inner races and preventing them from twisting. I found out after I finished that this is already in use in a couple commercial designs so the "original ideas" part didn't really work out, but I have some new ideas for next time now :)

So now that you have a picture in your head, make a picture on paper. Get a rough sketch, then hammer out all the dimensions. Start with the standards (e.g. spoke holes are nearly always 2.4mm, or 3/32" because the bike industry has a thing for bastardized metric representations of english sizes), then the dimensions constrained by other parts (e.g. the hub flanges can only be so far apart or else they'll interfere with the fork), then you magically only have a few things left to decide for yourself. Like my dad always says, butter the outside of the toast first and the inside takes care of itself.

Once you have drawings, find a lathe and start cranking handles and there you go!

Cartridge bearings are a thing, but you probably didn't see them in the shop very often because they're not meant to be adjusted or rebuilt. Once they develop slop, they're toast and you replace them with new ones, although a set of cartridge bearings should last at least 10k miles if properly sealed so that's almost a nonissue. Loose ball (aka cup and cone) bearings last longer and are less expensive, but you are restricted to designing hubs around a threaded axle, cups are hard to find on their own, and if you fuck up the cup they are harder to replace.

Safety is an issue, I suppose. I did calculations on spoke tear-out, compression and buckling on both the compression tube and middle section of the hub shell, and shear and compression in the endcaps. The bearing seats in the hub shell are very much overbuilt, so I didn't bother running any analysis. Still though, I've been thinking of making another one for destructive testing :D

Questions are no problem, if you have any more please ask!

« Last Edit: June 29, 2013, 09:46:17 AM by Russ »