N Yasui on mon 13 aug 12
I've converted my potters wheel into a jigger jolly machine referencing '=
=3D
The=3D20
Potter's Alternative' by Harry Davis and with the assistance of a welder =
=3D
friend.=3D20=3D20
I'm now attempting to turn the jigger chuck, but have been=3D20
unsuccessful. I've attached the diagram provided by 'Mold Making for Cer=
=3D
amics'=3D20
by Donald Frith. Conceptually it seems simple, but in practice ensuring =
=3D
that the=3D20
centre remains centre to turn the jigger moulds true is proving to be imp=
=3D
ossible.
Anyone turned a chuck? Lend some advice? Tips?=3D20
Thanks!
JRodgers on tue 14 aug 12
Michael, care to describe how that works and how you are set up? Sounds
intriguing. Suction cups on the back of the bat maybe?? (;<)
John Rodgers
On 8/14/2012 8:47 PM, Michael Wendt wrote:
> I use vacuum to hold my bats down to the wheel head
pdp1@EARTHLINK.NET on tue 14 aug 12
----- Original Message -----
From: "N Yasui"
> I've converted my potters wheel into a jigger jolly machine referencing
> 'The
> Potter's Alternative' by Harry Davis and with the assistance of a welder
> friend.
> I'm now attempting to turn the jigger chuck, but have been
> unsuccessful.
> I've attached the diagram provided by 'Mold Making for Ceramics'
> by Donald Frith.
No Attatchment or Link seems to be present.
> Conceptually it seems simple, but in practice ensuring that the
> centre remains centre to turn the jigger moulds true is proving to be
> impossible.
How is the Chuck ( Is it a 'Chuck' or a Mold Pattern? ) Blank being held to
the Wheel Head?
Usually a Chuck is what holds something...the Chuck would hold the Molding
Pattern.
> Anyone turned a chuck? Lend some advice? Tips?
> Thanks!
Michael Wendt on tue 14 aug 12
Jiggers and Jolly machines are robust. The culprits with conventional
potter's wheels are:
small diameter shafting for the wheel head.
The formula for plane moment of inertia ( which is one
of the factors that controls how easily something bends)
is:
Ix =3D I y =3D 1/4 pi * r^4
from this you can see that making a shaft 1" in diameter
instead of 3/4" ( the common size on most wheels) makes the shaft 3 times
stiffer!
Bearings on larger shafts can stand more force.
Additionally, wheel heads and frames are made fairly light weight in
anticipation the wheel will need to be moved.
The frame on a jigger is much more rigid so that the tools will not chatter
due to flexure much like a high quality metal lathe which uses extra heavy
bedways, tool posts and related structure to reduce flexure.
I would build a jigger - jolly wheel from scratch with the tooling
structures planned in. Also, the mold cavities would be designed in to be
easy to mount and hold...
I use vacuum to hold my bats down to the wheel head and it makes throwing
way easier since there is zero free play.
Regards,
Michael Wendt
how difficult something
----- Original Message -----
From: "N Yasui"
To:
Sent: Monday, August 13, 2012 5:45 PM
Subject: HOW TO TURN A JIGGER CHUCK
I've converted my potters wheel into a jigger jolly machine referencing 'Th=
e
Potter's Alternative' by Harry Davis and with the assistance of a welder
friend.
I'm now attempting to turn the jigger chuck, but have been
unsuccessful. I've attached the diagram provided by 'Mold Making for
Ceramics'
by Donald Frith. Conceptually it seems simple, but in practice ensuring
that the
centre remains centre to turn the jigger moulds true is proving to be
impossible.
Anyone turned a chuck? Lend some advice? Tips?
Thanks!
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