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Author Topic: splined 8mm shafts  (Read 1647 times)

zahc

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splined 8mm shafts
« on: December 08, 2015, 10:37:48 PM »
I want to make a miniature bicycle. I can do everything in my garage except the cranks, because they have to be splined to the crank axel and I can make splines. I might be able to make a square spline with files but I am not looking forward to it.

I could use a bolt for the axle, and use common wrenches modded with pinch bolts for the crank arms, but the tolerances are too sloppy.

There must be something I can re purpose from the junk yard.

The shaft can be from 1/4 to 3/4 inch diameter.
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zxcvbob

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Re: splined 8mm shafts
« Reply #1 on: December 08, 2015, 10:46:25 PM »
Does it have to be splined, or can it be square?  (and make it tapered so it snugs up nice and tight.)
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charby

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Re: splined 8mm shafts
« Reply #2 on: December 08, 2015, 10:46:39 PM »
engine valves?

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Brad Johnson

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Re: splined 8mm shafts
« Reply #3 on: December 08, 2015, 10:54:39 PM »
No way to cannibalize the gearset from a multispeed bicycle for the smaller sprockets?

Might also look to an office equipment repair company. Older copy machines were mechanically driver and full of chains, sprockets, and shafts. They might have one laying out back in the dump pile.

Brad
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Nick1911

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Re: splined 8mm shafts
« Reply #4 on: December 08, 2015, 11:33:30 PM »
If it doesn't need to come apart, I'd just weld it solid.
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zahc

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Re: splined 8mm shafts
« Reply #5 on: December 09, 2015, 07:43:11 AM »
I thought of 2 things: it could just be a round shaft with a pinch bolt or flatted for a set screw. How much torque is a 3-year-old going to generate anyway? Maybe it wouldn't slip. Or I could I could just tack weld it and grind the weld if I ever had to replace the bearings or chainwheel.
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Brad Johnson

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Re: splined 8mm shafts
« Reply #6 on: December 09, 2015, 10:08:11 AM »
It's for a kid to ride? I thought this was some kind of model project.

Don't waste your time trying to cobble something together that might work. Just buy one. There are 12" wheel bicycles for young'ns. IIRC they run in the $50-ish range.

Edit to add... I searched "12" wheel bicycle" on Amazon and got more than 200 results ranging from $50 to $200.

Brad
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HeroHog

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Re: splined 8mm shafts
« Reply #7 on: December 09, 2015, 10:37:16 AM »
Quote from: charby on December 08, 2015, 10:46:39 PM
engine valves?



If you pick a sodium filled valve you will be in a world of hurt!
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mtnbkr

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Re: splined 8mm shafts
« Reply #8 on: December 09, 2015, 11:25:28 AM »
Quote from: Brad Johnson on December 09, 2015, 10:08:11 AM
It's for a kid to ride? I thought this was some kind of model project.

Don't waste your time trying to cobble something together that might work. Just buy one. There are 12" wheel bicycles for young'ns. IIRC they run in the $50-ish range.

Edit to add... I searched "12" wheel bicycle" on Amazon and got more than 200 results ranging from $50 to $200.

Brad

This.  Kids outgrow bikes so fast until they hit their teens, it's not worth spending a lot on a bike unless they're dedicated and serious riders (they aren't at 3). 

The best value is good used "bike shop" bikes found on Craigslist and such.

Chris
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zahc

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Re: splined 8mm shafts
« Reply #9 on: December 09, 2015, 12:43:20 PM »
Of course I already know they make kids bikes. But thanks for the suggestion.

It is a hobby/modeling project that may be incidentally rideable.

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Brad Johnson

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Re: splined 8mm shafts
« Reply #10 on: December 09, 2015, 01:13:17 PM »
Motorcycle junk yard. Drive sprockets for 50-100 cc bikes.  Lots of variations. Some splined, some keyed.

Brad
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Nick1911

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Re: splined 8mm shafts
« Reply #11 on: December 09, 2015, 08:38:16 PM »
Unfortunitly, I think the real solution to your problem...



...involves buying a bridgeport.  =D
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charby

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Re: splined 8mm shafts
« Reply #12 on: December 09, 2015, 08:43:31 PM »
Quote from: HeroHog on December 09, 2015, 10:37:16 AM
If you pick a sodium filled valve you will be in a world of hurt!

only if you came in contact with dihydrogen monoxide
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Jim147

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Re: splined 8mm shafts
« Reply #13 on: December 09, 2015, 09:01:01 PM »
What about broaching them? Do you have a press and a heat source?
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zahc

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Re: splined 8mm shafts
« Reply #14 on: December 09, 2015, 09:03:35 PM »
No and no
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