I have posted photos on my web site in the epicyclic hub project of the parts I have finished machining. I’ve got about 30 hours into it now.
These six new photos are the ones at the bottom of the page. There are some managable errors that I have made so far but you’d have to use a micrometer to find them. That’s why I provided these low resolution shots.
Wow… looks pretty cool so far. How much is left?
Very, very exciting! 'Tis like watching Christmas slowly unwraping itself!
Let us all know how the Planetary Snacks taste… 
(inventors privilage)
Christopher
Most of it. I have the two hub halves to make which are somewhat complex but they are aluminum so the machining is pretty easy. I have the ring gear to modify by indexing some holes into it so that’s pretty easy. Tomorrow I’ll make all of the planet gear shafts and the bronze washers and press the planet shafts into the axle. I have the frame tab to make. Multiply that by two for two hub assemblies. Then I get to lace a wheel and build a unicycle.
They taste a bit like cutting oil right now. Sorry, I don’t have enough to share or I would send you a handful.
Harper,
All of these look great! I’m sure a lot of people will want to feel
what it
is like to ride a setup with this.
How about when you are setup to put the holes in the ring gear, adding
about
three times as many holes just to lighten it? It wouldn’t be an
additional
setup.
I’m curious - is there a need for six planetary gears? Why not just use
three? It would save even more weight and some friction. I weigh in at
about 220lb and wouldn’t come close to being able to strip those gears
on
any incline.
In awe,
Doug
“harper” <forum.member@unicyclist.com> wrote in message
news:a2tah5$sel$1@laurel.tc.umn.edu…
> I have posted photos on my web site in the epicyclic hub project of
> the parts I have finished machining. I’ve got about 30 hours into it
> now.
>
> http://www.harper.unicyclist.com/EpicyclicHub.htm
>
> These
> six new photos are the ones at the bottom of the page. There are some
> managable errors that I have made so far but you’d have to use a
> micrometer to find them. That’s why I provided these low resolution
> shots.
>
>
>
>
> –
> harper
> Posted via the Unicyclist Community - http://unicyclist.com/forums
Doug-
I don’t want it to break but I would like to have a big guy like you try to break it when you ride it. It will be interesting to find the weak link. I hope I don’t have it so over-designed that I can’t learn anything from it.
I don’t think I can remove a lot of weight by drilling holes in the ring gear or reducing the number of planets. The planets are pretty tiny already. The shafts are 0.8" long and 0.315" in diameter so they aren’t too huge either.
Right now I think most of the friction is in the big 6908 sealed bearing. The planets free wheel nicely on the shafts.
----- Original Message -----
From: harper <forum.member@unicyclist.com>
Newsgroups: rec.sport.unicycling
To: <rsu@unicycling.org>
Sent: Saturday, January 26, 2002 10:35 AM
Subject: Re: Planetary hub parts
>
>
> Doug-
>
> I don’t want it to break but I would like to have a big
> guy like you try to break it when you ride it. It will be interesting
> to find the weak link. I hope I don’t have it so over-designed that I
> can’t learn anything from it.
>
> I don’t think I can remove a lot of
> weight by drilling holes in the ring gear or reducing the number of
> planets. The planets are pretty tiny already. The shafts are 0.8" long
> and 0.315" in diameter so they aren’t too huge either.
>
> Right now I
> think most of the friction is in the big 6908 sealed bearing. The
> planets free wheel nicely on the shafts.
Harper, what is the pitch of your gears? How many teeth in the sun gear
and how many teeth in the ring gear? How about the width of the teeth?
Do you have needle bearings in the planetary gears or just a bushing
type
bearing? What is the material of the gears and are they heat treated for
hardness, wear?
Lowell
> Doug Massey wrote:
> > How about when you are setup to put the holes in the ring gear,
adding
> > about three times as many holes just to lighten it? It wouldn’t be
an
> > additional setup.
> > I’m curious - is there a need for six planetary gears? Why not
just use
> > three? It would save even more weight and some friction. I weigh
in at
> > about 220lb and wouldn’t come close to being able to strip those
gears
> > on any incline.
>
>
> –
> harper
> Posted via the Unicyclist Community - http://unicyclist.com/forums
>
> rec.sport.unicycling mailing list -
www.unicycling.org/mailman/listinfo/rsu
Lowell-
The pitch is metric, module 1.0
The sun gear has 30 teeth
The ring gear has 60 teeth
The planet gears have 15 teeth each
The gear width is 10mm or .3937"
The planets run directly on the shafts
The gears are unhardened steel, oxide coated
Harper
My thinking on gear ratios involving sun and ring gears is a little
fuzzy
but I think you are using a 1.5 to 1 ratio.
> Lowell-
>
> The pitch is metric, module 1.0
Module 1 is .03937 inches pitch diameter per tooth.
> The sun gear has 30 teeth
That would be 1.1811 inches pitch diameter.
> The ring gear has 60 teeth
That would be 2.3622 inches pitch diameter.
> The planet gears have 15 teeth each
The planet gears would be .59055 pitch diameter.
> The gear width is 10mm or .3937"
Considering the limitations of size in a unicycle wheel hub width
I would consider going a little wider with the gears to gain strength
and longer life, if possible.
> The planets run directly on the shafts
I don’t know what you are using for shafts but what is known as
dowel pins are available fairly cheaply in lots of sizes. They
are smooth ground finished and hard. They are commonly
used to pin die parts together in punch press dies. Very tough
and hard.
> > The gears are unhardened steel, oxide coated
The oxide coating is a start but small gears and other parts
can be sent to a heat treater and have a carbonizing process
that will harden them several thousanths of an inch thick.
That still leaves a non-brittle core of steel for shock strength.
Generally that does not warp them but leaves a surface coating
that needs to be smoothed with liquid hone. That is a stream
of oil with fine abrasive in it that shines the surface some. Lots
of heat treaters can do that for you too.
Just a few thougths I thought I’d pass along, my old company
does make gears of that size, but not the ring gear, and we often
had them hardened for wear. I am not trying to get any business
as I’ve been out of it for some time now.
Lowell
> > Lowell Terry wrote:
> > > Harper, what is the pitch of your gears? How many teeth in the
sun gear
> > > and how many teeth in the ring gear? How about the width of the
teeth?
> > > Do you have needle bearings in the planetary gears or just a
bushing
> > > type bearing? What is the material of the gears and are they
heat
> > > treated for hardness, wear?
> >
> >
> > –
> > harper
> > Posted via the Unicyclist Community - http://unicyclist.com/forums
> >
> > rec.sport.unicycling mailing list -
www.unicycling.org/mailman/listinfo/rsu
The gears are the widest commercially available stock size of an appropriate diameter. The gear width is effectively increased by a factor of six in that there are six planet gears. This is a prototype which may not actually work as I planned. (Wouldn’t that be a shock?) I would hate to have used expensive, hardenable materials. Since the gears had to be modified I couldn’t very well buy hardened ones. The shafts are ground 440 SS 8mm shaft stock. That is why the planet gears freewheel so nicely on it. They are bored to fit an 8mm shaft. Dowel pins are oversized so I would have to turn down a hardened dowel pin or ream out an already precision bore in the planet gears. These are all things considered in the design phase of this project. I am in the construction phase of the project. Costs had to be considered in a one or two off experimental project like this. Some tradeoffs had to be made. I could have saved alot of space by machining my own bearing races onto the shaft and cutting race nuts for loose balls all into hardenable material. This is extremely time and cost intensive and difficult to design as well. Stock ball bearings and stock gears are CHEAP compared to designing captured ball bearings and having gears cut.
Hi Harper -
I’ve been working on a 24" frame design and have made several prototypes. Seems to me that my frame would work pretty well with your hub … I’d be glad to donate a frame along with the appropriate adapter for you to use on your project.
The frame I’ve got is intended for Muni but that shouldn’t matter. I’ve got an Autocad drawing of the existing frame showing your hub installed as well as a concept frame using your hub. The concept might be interesting to you since I think it could eliminate a couple of bearings in the hub.
Let me know if you’re interested and I’ll e-mail you the drawing.
Steve Howard
Steve-
E-mail me the drawing, please. Just send it to my harper@unicyclist.com address. If I can’t extract it from there I will forward it to myself at various other places. Do I need anything special to view the drawing? I can view up to version 14 AutoCAD. Otherwise, a PostScript, .pdf, .jpg, or .gif would do.
Post it if you can so others may view your design. Several tinkerers here like to look at other peoples’ stuff. If it’s a frame for MUni, Scott Bridgman the muniac, scott@muniac.com, will probably be interested.
I already have the frame I plan to use. I built the hub assuming it would be put into a 24" Torker frame which is what I bought for it. Cheap stuff for a prototype again.
Hey there,
I apologize for my ignorance, but the whole point of this is to just change
the gear ratio? Or is there something vitally important I’m missing?
Dustin
Zupancic
“Uni-Pickle”
“Lowell Terry” <yoda@socket.net> wrote in message
news:mailman.1012117835.30992.rsu@unicycling.org…
>
>
> Harper
>
> My thinking on gear ratios involving sun and ring gears is a little fuzzy
> but I think you are using a 1.5 to 1 ratio.
>
> > Lowell-
> >
> > The pitch is metric, module 1.0
>
> Module 1 is .03937 inches pitch diameter per tooth.
>
> > The sun gear has 30 teeth
>
> That would be 1.1811 inches pitch diameter.
>
> > The ring gear has 60 teeth
>
> That would be 2.3622 inches pitch diameter.
>
> > The planet gears have 15 teeth each
>
> The planet gears would be .59055 pitch diameter.
>
> > The gear width is 10mm or .3937"
>
> Considering the limitations of size in a unicycle wheel hub width
> I would consider going a little wider with the gears to gain strength
> and longer life, if possible.
>
> > The planets run directly on the shafts
>
> I don’t know what you are using for shafts but what is known as
> dowel pins are available fairly cheaply in lots of sizes. They
> are smooth ground finished and hard. They are commonly
> used to pin die parts together in punch press dies. Very tough
> and hard.
>
> > > The gears are unhardened steel, oxide coated
>
> The oxide coating is a start but small gears and other parts
> can be sent to a heat treater and have a carbonizing process
> that will harden them several thousanths of an inch thick.
> That still leaves a non-brittle core of steel for shock strength.
> Generally that does not warp them but leaves a surface coating
> that needs to be smoothed with liquid hone. That is a stream
> of oil with fine abrasive in it that shines the surface some. Lots
> of heat treaters can do that for you too.
>
> Just a few thougths I thought I’d pass along, my old company
> does make gears of that size, but not the ring gear, and we often
> had them hardened for wear. I am not trying to get any business
> as I’ve been out of it for some time now.
>
> Lowell
>
> > > Lowell Terry wrote:
> > > > Harper, what is the pitch of your gears? How many teeth in the sun
gear
> > > > and how many teeth in the ring gear? How about the width of the
teeth?
> > > > Do you have needle bearings in the planetary gears or just a
bushing
> > > > type bearing? What is the material of the gears and are they heat
> > > > treated for hardness, wear?
> > >
> > >
> > > –
> > > harper
> > > Posted via the Unicyclist Community - http://unicyclist.com/forums
> > >
> > > rec.sport.unicycling mailing list -
www.unicycling.org/mailman/listinfo/rsu
The whole point that Harper is pursuing is to build a geared hub,
which has a 1.5 to 1 gear ratio as opposed to 1 to 1 as in regular
direct-drive unicycles. I think this is not “just” a change but
something vitally important.
Klaas Bil
On Sun, 27 Jan 2002 19:15:59 GMT, “Zupancic” <zupancic5@home.com>
wrote:
“To trigger/fool/saturate/overload Echelon, the following has been picked automagically from a database:”
“VLF, 64 Vauxhall Cross, Lybia”