I've used several different methods for reverse chucking of bowls. All seem
to work okay, but some are easier and less time consuming/labor intensive
than others. I don't have Adjusta-Jaws (Cole jaws) for my Vicmarc chuck,
but am considering getting a set.

What is your preferred method for reverse chucking? And why?

TIA,
Max

Hello,

I use three main methods to reverse chuck bowls and platters. 1.) Jumbo jaws
outfitted with sacrificial wooden faces. 2.) Large 3" to 4" thick round wood
sections attached to a faceplate and 3.) Extended friction cylinder chucks.
I've yet to jump on the vacuum bandwagon, as I rarely encounter a form that
cannot be easily rechucked with one of the above methods.

1.) I use the wooden jaw modified jumbo jaws the most. I do not use the
plastic knobs for securing bowls. These are the 20" diameter set, outfitted
with 3" thick wooden faces. To rechuck a bowl, the jaws are extended
slightly, a recess is turned in the wooden face that matches the rim of the
bowl. The bowl is then loaded into the recess and the jaws secured. This
works very well and offers near 100% contact with the rim. In addition, no
tailstock support is required with these jaws, so you can completely turn,
sand and finish the piece under power. Very delicate rims can be held this
way without damage. It's easy to add tape to the outside of a bowl, if the
situation warrants this additional precaution as well. Think of this method
as an adjustable friction chuck... :-) I use this method 90% of the time for
my production and artistic work.

2.) This is a standard friction chuck type mounting method. I prefer soft
Maples for the wooden face of the jam/friction chuck. This type is only used
with very small bowls that cannot be mounted in the jumbo jaws. These work
well, but require the tailstock to be used, or they must be taped onto the
face for finish turning. I use this method 5% of the time on production and
artistic pieces.

3.) The extended friction chuck is a cylinder of wood (various lengths) with
a turned dovetail tennon turned on one end and a slight concavity turned on
the other end of the cylinder. This cylinder is mounted in a scroll chuck's
dovetail jaws and secured. The bowl is then inverted over the end of the
cylinder and the tailstock is brought up and secured. This style works well
for natural edge bowls. The end of the cylinder is covered with smooth
leather, or high density foam. The cylinder have been soaked in a thin,
penetrating epoxy to harden the cylinder. The bottom of the bowl is finished
down to a 1/16" tennon and finished off by hand after dismounting. I use
this method 3% of the time on production and artistic pieces.

3A.) A favourite variation of #3 involves the use of ultra high density foam
faces, in lieu of the wooden cylinder. This is the same foam used when they
built the Alaska pipeline to protect the Arctic Tundra. You can run a truck
over this stuff without any damage. Sections of the foam are glued together
and trued up with a slight concavity at the end. The opposite end of the
foam is glued to a wooden keeper, which has a dovetail spigot for securing
it into a scroll chuck. This acts as a basic friction chuck, but it is
non-maring and allows very delicate pieces to be finish turned without fear
of damage or burnishing. I use this method 2% of the time with artistic
pieces.

Good luck to you and best wishes in all of your woodturning endeavours!
--
Better Woodturning and Finishing Through Chemistry...

Steven D. Russell
Eurowood Werks Woodturning Studio
The Woodlands, Texas

Machinery, Tool and Product Testing for the Woodworking and Woodturning
Industries

³Woodturning with Steven D. Russell² Volume #1 CD ROM * Available
Volume #2 CD ROM/DVD Video * Available Soon

On 8/25/04 10:18 AM, in article
.net, "Maxprop"
wrote:

I've used several different methods for reverse chucking of bowls. All seem
to work okay, but some are easier and less time consuming/labor intensive
than others. I don't have Adjusta-Jaws (Cole jaws) for my Vicmarc chuck,
but am considering getting a set.

What is your preferred method for reverse chucking? And why?

TIA,
Max

If you use a recess, you can finish the bottom prior to reversing to hollow.

If you're an outside gripper, you can reverse to jam between a tapered (for
centering) plywood circle and the tailstock, trimming the final tip off with
a curved knife.


"Maxprop" wrote in message
hlink.net...
I've used several different methods for reverse chucking of bowls. All
seem
to work okay, but some are easier and less time consuming/labor intensive
than others. I don't have Adjusta-Jaws (Cole jaws) for my Vicmarc chuck,
but am considering getting a set.

What is your preferred method for reverse chucking? And why?

TIA,
Max

All the methods I know of( except mine, of course) require either turning a
face plate grooved to match the bowl lip or turning an extra amount on the
bottom to match a chuck. What I found in Wood Magazine # 45, Sep 91, p.
84 and stupidly listed in their on-line index as being for plates is this:

I turned one disc to the max diameter my lathe would take. Then turned a
second set of discs, same diameter but different size holes at the center,
padded the hole insides with rubber. Glued a piece of scrap wood to the
bowl bottom, fastened that to a face plate, turned the outside and inside
and finished them. Removed the face plate,then put the bowl on my solid
disc, picked the second disc of appropriate diameter and fastened it with
matching bolts to the base disc, turned away the scrap wood and finished the
bottom. Just finished two today and it works like a charm. If you can find
that wood article, you should read it first. There are probably more
details than I am giving here.

Bob Moody

If you have the Vicmarc chuck, why not make a set of jaws?
http://www.aroundthewoods.com/jaws.shtml
--
God bless and safe turning
Darrell Feltmate
Truro, NS, Canada
http://www.aroundthewoods.com

"Steven D. Russell" wrote in message

Hello,

1.) I use the wooden jaw modified jumbo jaws the most. I do not use the
plastic knobs for securing bowls. These are the 20" diameter set,
outfitted
with 3" thick wooden faces.

What is the configuration of the wooden faces, Steven? Do you just secure
some rectangular strips to the jumbo jaws, or triangular sections, or what?

I hadn't thought of this option--I like the concept.

Max

"Bob Moody" wrote in message

I turned one disc to the max diameter my lathe would take. Then turned a
second set of discs, same diameter but different size holes at the center,
padded the hole insides with rubber. Glued a piece of scrap wood to the
bowl bottom, fastened that to a face plate, turned the outside and inside
and finished them. Removed the face plate,then put the bowl on my solid
disc, picked the second disc of appropriate diameter and fastened it with
matching bolts to the base disc, turned away the scrap wood and finished
the
bottom. Just finished two today and it works like a charm. If you can
find
that wood article, you should read it first. There are probably more
details than I am giving here.

This sounds like the same technique Judy Ditmer describes in her book,
"Basic Bowl Turning." (Schiffler Pub.) I haven't tried it yet, but it seems
like a reasonable method for fabricating a reverse chucking apparatus that
will work with many different bowls of similar diameter.

Max

"Darrell Feltmate" wrote in message
...
If you have the Vicmarc chuck, why not make a set of jaws?
http://www.aroundthewoods.com/jaws.shtml

I'd already checked out your website and noted these jaws before posting my
original inquiry. Having a bit of Scots blood I'm always up for saving a
shilling or two. I've considered buying some jumbo jaws, but will probably
fabricate them from your design. Thanks.

The reason I made this inquiry was to see if you experienced turners used
jumbo jaws for reverse chucking. So far it would appear that a variety of
methods are used.

Max

Max, Usually I reversed the piece and jammed it between a tail center,
narrow enough to expose all the bottom except a tiny nib, and some sort
of driving device that didn't damage the vessel. The bottom was cleaned
up, decorated or not, sanded and later the nib was carved off.

I made a narrow revolving tail center that extended about 2in. from its
bearing. This made the bottom more accessible.

The variations mostly had to do with the driving device that jammed the
vessel against the tail center without damage. Usually this was a simple
wooden cylinder held by the scroll chuck, the other end knobbed and of a
size and shape to fit the cavity bottom. The knob was covered with a
material that would resist slipping yet not score the vessel. Ex. vinyl
sheet, sandpaper, leather, canvas, balloon wrap. I've never used it, but
urethane foam can be molded into a form fitting driving knob.

I threaded different lengths of 5/8 in. CR bar to hold various sized and
shaped knobs. To extend, they could be screwed together like a gun
barrel swab or maybe slipped over a tube like a trombone. I threaded a
dovetailed disc for the spindle ends to fit into. Holding the disc in
the scroll chuck saved the time taken to remove the chuck for a separate
attachment.

I've never used a Cole jaw/scroll chuck set up, but I have used a large
aluminum plate with a foam/vinyl backng to jam a smooth rimmed vessel.
IMO, faceplate clamps, dogs and such are best left to machinists, Also
jamming a vessel's rim into a turned groove on a wood disc was a pita
and not worth the time spent.

I've considered making an 'internal compression chuck' by inserting a
small inflatable ball attached to a shaft and inflating it to fit just
snug enough to drive. Sort of a soccer ball on a stick. I haven't got
roundtuit yet or even thought it through and I probably never will.

The use of a vacuum chuck is self evident, but the details are
complicated and probably should be the subject of an entire thread.

Max, I used the past tense in the nonsense above because I mostly
(87.3%) use a faceplate and sacrifice some wood, which is plentiful in
Fl, That way the blank is firmly held and I don't need to reverse the
piece to finish its bottom.

Arch

Fortiter,


http://community.webtv.net/almcc/MacsMusings

Hello,

The wooden faces are fabricated from solid sections of a soft Maple, or
Poplar and are cut to match the pie shaped pieces of the aluminium jumbo
jaws. The jaw mounting area is cut-out in the wood face to allow attaching
the jaws with the two screws in the chuck body. The jaw faces are 3" thick,
sometimes a bit more and are secured from the rear of the jaws with screws
in the furthermost holes in the centre and the outer edges. These areas are
not typically in the area of the jaws you will be using when turning the rim
recess.

I have used many different methods to rechuck bowls through the years and I
like my wooden face modification the best. When set-up, the rechucking is
fast and accurate. Many times, the rim recesses can be used for several
bowls, if the diameter is the same, or nearly the same. When doing a long
production run of bowls, I can frequently use a turned recess many times
before it needs tweaking.

I have used this as the primary method to rechuck several thousand bowls
over the last few years. It works very well and is very fast. Time is money
in a production studio, so if I keep something around the studio and use
it, it's because it works. I use the large jumbo jaws offered by Vicmarc on
a dedicated chuck for rechucking. When the wooden faces wear out, simply
replace them and you're good to go for a few hundred more bowls. Works for
me... :-) Take care and all the best to you and yours!

--
Better Woodturning and Finishing Through Chemistry...

Steven D. Russell
Eurowood Werks Woodturning Studio
The Woodlands, Texas

Machinery, Tool and Product Testing for the Woodworking and Woodturning
Industries

³Woodturning with Steven D. Russell² Volume #1 CD ROM * Available
Volume #2 CD ROM/DVD Video * Available very soon...

"Arch" wrote in message

Max, I used the past tense in the nonsense above because I mostly
(87.3%) use a faceplate and sacrifice some wood, which is plentiful in
Fl, That way the blank is firmly held and I don't need to reverse the
piece to finish its bottom.

Guess I'm not envisioning this method very well. I'm assuming you're
talking about sacrificial wood at the base, similar to a glue block? So, if
you part the bowl off, don't you need to finish the bottom? I'm so
confused. :-)

Max

Darrell....is there a way that one could mount the wood jaws to the Vicmarc
chuck with the need to remove the jaws. Is there a way to make an adapter
that could be held in the jaws with the wood jaws attached. I hate removing
jaws each time I want to use the wood jaws (mine is made of aluminum).
Sorry I answered this post with a question rather than an answer......Ralph
"Darrell Feltmate" wrote in message
...
If you have the Vicmarc chuck, why not make a set of jaws?
http://www.aroundthewoods.com/jaws.shtml
--
God bless and safe turning
Darrell Feltmate
Truro, NS, Canada
http://www.aroundthewoods.com