Re: 24" Custom Frame - 1st Design

Andrew, the bearing holders on your frame look fine, except for one
thing:
Make SURE they have retaining lips on each side. If you can't get them
on each side, then make the retaining lip on the outside. This is
really important. I have ridden frames without these libs, and when
powering up hill the frame will slide off the bearing.

The 10mm thick steel plate for the top of the crown is excessive. I
would reccomend around 3-4mm. even better, try 2.5mm with a gusset that
goes all the way under the crown (instead of triangles on the sides),
like on the 2004 KH model.

As for the fork legs, just borrow a KH frame and take the specs off
that.

Miyata seatposts suck. I've bent one, and that's enough for me. Get a
thomson and a rail adapter if you care about your unicycle. As for
diameter, go with 27.2mm ideally. If not, 25.4 is a good size. Whatever
you do, avoid 22.2mm. It's a uselessly small size.

You define the thickness of the tube's walls as "wall thickness". Thus,
internal diameter (ID) + 2(wall thickness) = outside diameter. This
applies to ovalized tubing aswell.

I've been trying to use metric for your sake, but when it comes to wall
thicknesses, i can't do that. I don't have a conception for a fraction
of a millimeter, so you'll want a calculator for this part. 1 inch =
25.399mm, but you can round to 25.4mm. So, anyways, i'd use a 0.065"
wall thickness, although you could go with a bit less, maybe 0.055, but
I wouldn't go less. You don't want too thin walls because the frame
will be as easy to dent as a soda can,regardless of its strength.

If you go with a 27.2mm ID seattube, you could go with 0.050" wall
thickness, at least. I wouldn't go less, for the reasons highlited
above.

Another reason to go with a lardger dia. seatpost/seattube is because
it will mean a larger surface area to be welded to the crown, which
will mean more stiffness, something to be concerned about in this crown
design (because this crown has a very thin attachment plane for the
seattube).

One last thing to note: You can do this with trig, or just play around
with it. The flange for the top of the crown (that 10mm thick plate you
called out) must be long enough (front-back) that when it is tilted
forward at a 30* angle, the seattube will fit on the top of it, with
some room to weld. if it's too short, the seattube will run off the
edge, and be ugly. The same goes for the plate and the forklegs. What
I'm getting at is the specs of these parts are more interconnected than
they seem.

--
gerblefranklin

http://gallery.unicyclist.com/Trials-Muni

Nick's main man.

"I love freedom dearly, ideally, in theory, but in reality we're not
there yet--Not nearly."--Cold Duck Complex
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wow, this is an OLD thread.

I love how stuff gets resurrected by accident sometimes.

--
Fuego

"Get off my Property before you sue me!"
-Morons everywhere.

"Wow, I think it's clear that gimp does a much better job of saving
gifs than mspaint."
-Phlegm
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Hahaha, yeah. Thanks for all the tips Bevan, but that frame design is
-very -out-dated. I will keep them in mind though.

See my main custom frame thread for an update if you're interested.

Andrew

--
andrew_carter

...well that's what i think anyway.
*'unicycling tips and tutorials' (http://www.unicycle.2ya.com) |
'my photos and videos' (http://gallery.unicyclist.com/andrew) |
'\\"dancing about architecture\\"'
(http://www.dancingaboutarchitecture.com.au)* (coming soon...)
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Oops. Well played by me🙄 .

--
gerblefranklin

http://gallery.unicyclist.com/Trials-Muni

Nick's main man.

"I love freedom dearly, ideally, in theory, but in reality we're not
there yet--Not nearly."--Cold Duck Complex
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