vince pitelka on mon 23 sep 02
I just viewed the Jolyon Hofsted article on making a $75 electric wheel on
the CM website, and I must say I am a little appalled. I see so many things
wrong with this design, and with the incredible vagueness of the
instructions. I am wondering if ANYONE has ever built one successfully.
Anyone out there using a Hofsted power wheel on a regular basis?
I cannot see any way that a clamp-on electrical plug could possibly serve as
the drive member for such a wheel. It would not be centered to begin with,
and such electrical plugs are not made from the kind of hard friction rubber
you need for such a drive member. The Hofsted wheel is made from a car rim
poured full of plaster, and that is suppose to give it the weight to work
properly. The wheel bearings would certainly be smooth running, but
consider that an electric/kick wheel has a very heavy flywheel, and once you
bring it up to speed with the motor, it keeps working for quite a while.
With the Hofsted design, almost as soon as you quit applying motor power and
start throwing, the wheel would slow down QUICK.
Hofsted presents this design as a variable speed wheel, but that is a false
assertion, because the motor only has one speed, and the only way the speed
is variable is that you can initially speed the wheel up as much as you want
using the motor drive, but as I said, as soon as you start throwing, it will
slow down QUICK. Without the true flywheel momentum of a true electric/kick
wheel, you would need to be using the power drive almost constantly, and
would continually be fighting with the speed of the wheel. Even if you used
a commercial rubber drive member, made for an electric/kick wheel, in this
application it would wear out very quickly.
This wheel seems to me to be a real Rube Goldberg. I wonder if Hofsted ever
tested the design before writing about it? Again, has anyone out there ever
built this wheel, and how did it work?
Thanks and best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
John Baymore on tue 24 sep 02
Vince,
I haven't seen the article you mention..... but the comment below leads m=
e
to a thought......
The Hofsted wheel is made from a car rim
poured full of plaster, and that is suppose to give it the weight to work=
properly. The wheel bearings would certainly be smooth running, but
consider that an electric/kick wheel has a very heavy flywheel, and once
you
bring it up to speed with the motor, it keeps working for quite a while.
With the Hofsted design, almost as soon as you quit applying motor power
and
start throwing, the wheel would slow down QUICK.
If you've ever tried a Korean / Japanese style kickwheel........ they hav=
e
very little momentum. They =
require constant kicking while throwing. With each "kick" (often actuall=
y
a pull backward with the foot..... not a kick away) they speed up and the=
n
immediately slow down. They are made almost totally from wood... so the
"flywheel"
really is very light. The thick wood wheelhead is almost as much mass as=
the flywheel you kick .
So the car rim full of plaster probably supplies a somewhat similar "feel=
"
as to how fast it slows down when
not actually powered. So if this type of wheel is something that you are=
used to using and like...... the lack of =
momentum when compared to a "western style" kickwheel may not be looked a=
t
as unusual.
If this is not basically intended as a motorized kickwheel design........=
.
but some sort of power-only wheel........ then the general premise sounds=
a
bit flawed.
Your comments about a electrical plug acting as a power transfer device
have intrigued me..... and I guess I'll have to go look at this particula=
r
design. Knowing your background........ if you are skeptical about it
working.... my guess is that you are correct. Sounds like it might
work...... for about 5 minutes .
Best,
..............................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JohnBaymore.com
JBaymore@compuserve.com
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