Using Chucks for large hollow forms?

[John Sincerbeaux]

Hello all,
Does anyone here use large chucks for turning large hollow forms? Large, as in the 16"+ range

Assuming you have a large lathe and a large chuck, what is the largest HF's you have turned HF's on, or heard of been turned on using a chuck. Vicmarc shows a 20" capability for their 120 chuck. I know faceplates are king for doing large work, but am just curious what guidelines/limits guys use for using chucks.

Thanks

John

[Alan Trout]

It really depends if the hollow form is supported with a rest. It does not take much of a tenon to turn a deep form with at steady rest. I have done 16" with a 2.5" tenon without trouble with my Strong Hold chuck with the vessel supported in a steady rest. A VM120 will work just fine.

Alan

[Steve Schlumpf]

I agree with Alan that using a steady rest makes a huge difference. Also, the experience of the turner makes even more of a difference when turning large forms. If you know how to put metal to wood - without - causing catches, then the amount of tenon used isn't as important as support for the form.

[Faust M. Ruggiero]

David Ellsworth teaches hollow forms with the piece mounted between centers until the outside shape is determined. Then he flattens the bottom and mounts on a faceplate. Of course, you need to design the form allowing the bottom to fall within the screw holes. David teaches with a 6" face plate. I am sure the face plate is wonderful as a learning tool and gives a great sense of confidence, however, I find it restrictive. I still turn the outside shape between centers but now I usually turn a tenon and mount in a chuck. I would not hesitate to use a faceplate if the shape or size of the hollow form demanded it.

[Thom Sturgill]

Lyle Jameison calls the steady rest an engineering solution to a [problem that shouldn't exist. He strongly advocates the use of faceplates.
While I have used the centers to tenon route myself, most of my turnings are much smaller. Nova gives limits for their jaws, and only the powerjaws come close to holding 16".

[Dennis Ford]

Using a chuck is a convenience for me, it saves a little bit of wood and a couple of minutes of mounting time. That is great for a turning that takes 10 - 20 minutes to finish but seems meaningless when talking about a large hollow form. There is nothing wrong with using a chuck if it holds for you but launching a large blank or two will make you re-consider (if you survive). Also a tall hollow hollow form puts a LOT more stress on the mounting than a short piece with the same diameter.

[Joe Meirhaeghe]

I've turned & hollowed 24" dia. 450 plus lb logs with a 2 1/2" to 3" dia. tenon with a 1/4" long dovetail. That said I shape the vessels between centers & ALWAYS us a steady rest for hollowing.
The tenon is just a means to drive the piece when turned this way. It is not supporting the weight of the log it's just used to drive the piece.

[Dwight Rutherford]

I agree with Joe , also turn between centers and use a steady, always.

[robert baccus]

My go to for 100#+ X 22"+ vases is a single screw and 3 " glueblock for all operations including finishing. I always use a steady rest by by oneway. Roughing out is between centers to make a good glueface and square ends. I use great wood for GB and fresh thick CA. Dismounting is by parting tool/saw. Mine are always done on green wood which dictates the CA glue.

[Thom Sturgill]

My go to for 100#+ X 22"+ vases is a single screw and 3 " glueblock for all operations including finishing. I always use a steady rest by by oneway. Roughing out is between centers to make a good glueface and square ends. I use great wood for GB and fresh thick CA. Dismounting is by parting tool/saw. Mine are always done on green wood which dictates the CA glue.

Doesn't the worm screw cause an issue if you want to reverse for sanding? A small faceplate would probably be just as stable.

[Jim Silva]

I played with chucks vs faceplate quite a bit and I have to say that the faceplate is by far the best method of holding a large hollowform. (or medium size for that matter)
I'm a huge chuck proponent form most all other applications but on hollowforms, especially taller ones the faceplate is the only way to go IMO.

I start between centers and I don't use a steady and have significantly more vibration with a proper tenon than when mounted on a plate.

[robert baccus]

Chuck, I power sand mostly but never have backoff's on the single screw when reverse sanding. There is very little torque involved and I tighten the GB on with a big pair of channel locks. The problem with faceplates is putting in screws into green endgrain. I haven't lost a big one yet. Do a scrap/test with CA on the lathe to destruction. The only screws I ever use is on a small faceplate(three 1.5" square head screws) to rough out hollow forms or bowls and make a holding on the bottom. I use mostly glueblocks but dovetails also. Never tenons--I,ve had bad luck grabbing green wood tenons. I don't throw the bowls but knock them out of line--grrr.

[Jake Helmboldt]

So I'm curious to know more from those of you that use a faceplate, specifically regarding what you do to finish the bottom of your HF after it is turned. I launched a medium vase and cracked it as I neared completion hollowing. Joy!

So I've turned the bottoms off of bowls with jamb chucks, etc, but what do you use for HFs to clean up the bottom and eliminate the screw holes?

[John Sincerbeaux]

Thanks guys,
The guy that is mentoring me turns only large hollow forms 20-24" and only uses a 6" faceplate. End grain or face grain and he has never had one come loose/off. He also never uses a steady rest. I ask about chucks because my first HF's will be around the 12" size and I think it would be nice to learn to use chucks up to their safe limits.

[Dennis Ford]

Jake:
I jamb chuck vases a couple different ways.
* turn a cylinder (mounted on a chuck or faceplate) long enough to reach the bottom of the vase and use that to drive the vase between centers.
* turn a disk (mounted on a chuck or faceplate) with a ledge that fits (not tightly) into the opening of the vase, cushion with a paper towel and turn the vase between centers.
Either method requires that you carve off a small nub where the tail-stock was.

John;
Exploring the "safe limits" of a chuck is not a good plan until you have explored other ways of making hollow forms fail.

[robert baccus]

Good advice yeah.

[Thom Sturgill]

So I'm curious to know more from those of you that use a faceplate, specifically regarding what you do to finish the bottom of your HF after it is turned. I launched a medium vase and cracked it as I neared completion hollowing. Joy!

So I've turned the bottoms off of bowls with jamb chucks, etc, but what do you use for HFs to clean up the bottom and eliminate the screw holes?

If the Hollow form comes to a narrow base, the screws could be set to be outside the form. The lower third is not turned until you reverse it. Otherwise you leave wood where the screws are out of the design and part off past them being sure that you ARE past them as they can ruin a tool.

[John Keeton]

Lot of great comments here. As Steve Schlumpf and Joe alluded to, the use of a steady with hollowing changes the dynamics and the chuck then becomes largely a driving mechanism. I don't use faceplates to hollow and don't have any problems, but I also use a steady.

Clearly, without a steady, a faceplate becomes a near necessity for larger forms.

[john taliaferro]

Yes always use a steady when you can , But i have removed it and slowed the speed to finish some large ones . I fit a plug and bring the tail stock back when possible .

[Fred Belknap]

I hardly ever use a faceplate and have turned some rather large bowls, 16+". They are not that tall so I haven't had a problem and I almost always use a tenon with a Stronghold chuck and the largest jaws. I have and use a Oneway steady and can't see that it would help to hold the piece in the chuck as it is only a two point contact steady. It counter acts against the pressure put on the cutting tool very well but doubt it would be much help in the event of a catch, not that I ever get one;). I can see where a three or four point contact steady would support the weight of the turning. Most of my hollowing is limited to less than 8" as I only have the Monster articulating system. I have been thinking about getting a system that I can hollow up to around 16" and am wonder it my set up will have to be adjusted somewhat, like a different steady and a faceplate. The faceplate I have is the one that came with the PM3520B and I think it is only 3".

[Jim Silva]

So I'm curious to know more from those of you that use a faceplate, specifically regarding what you do to finish the bottom of your HF after it is turned. I launched a medium vase and cracked it as I neared completion hollowing. Joy!

So I've turned the bottoms off of bowls with jamb chucks, etc, but what do you use for HFs to clean up the bottom and eliminate the screw holes?

Jake,
I generally pre-drill pilot holes in wood that's prone to cracking (or very wet wood) so that my stainless screws dont' put too much stress into the blank. When I do this I find that I rarely have cracking on the bottoms from the faceplate screws. (Turning poor pieces of wood is another story lol)

Finishing the bottom... I turn most vases and HF's green. I part it off the faceplate so I don't have screw holes to contend with (you have to plan on the depth of your screws). I typically coat the bottom of the vessel with sanding sealer and set it to dry for a week or two. I remount with a jam chuck (cone shaped with a pad usually) and a brad point live center and dress the bottom of the form. I don't re-turn the form itself. Then I just use a very sharp chisel to hand pare the nib from the bottom and sand. It's pretty easy and you shouldn't have any tearout with sharp tools.

Your mileage may vary ;)

Jim