bottom of bowl question

Re: bottom of bowl question

John Lucas

>If it's a bowl I can't mount any other way I simply bring up the tailstock and put light pressure to hold it in place and then rotate it by hand to see if it's centered. I move the toolrest up so there is a gap between the foot and tool rest., This makes it easier to see the high spot. Then I move the bowl around until it's centered as good as possible and tighten the tailstock and turn it.

If the bottom is thin I remove the center point and use the cup center. I don't turn the bowl as fast as I usually do. I've turned a lot of bowls like this before I got my vacuum chuck and large jaws, etc. John

Re: bottom of bowl question

DWFII

>John,

Thanks...I see what you are saying. However, the next question is: What do you use at the headstock?

DW

In the High Desert of Central Oregon

Re: bottom of bowl question

George Van in WI

>John, how do you remove the center point from a Oneway live center? I think that is what you have said you use. I dont see any set screw.

Re: bottom of bowl question

Ron in Drums PA

>Do you still have the center mark from the tail stock when you first formed the tenon?

Re: bottom of bowl question

George Van in WI

>Never mind John, I downloaded a manual from the Oneway site. Too simple to be easily understood!

Re: bottom of bowl question

Carole in VA

>Have you tried a jam chuck? Also, if you have Bill Grumbine's video, he shows you how to make a nice little contraption out of plywood to finish off the bottoms of bowls.

Re: bottom of bowl question

DWFII

>Yes, I do.

DW

In the High Desert of Central Oregon

Re: bottom of bowl question

John Lucas

>Most of the time I just stick a piece of closed cell foam over my chuck or a faceplate. It it's a deep bowl I'll use a faceplace with a scrap of wood on it and then put the foam over that.

I use a Nova live center most of the time for this. I have the powermatic copy of the Oneway live center but without having it in my hand I can't remember how to get the center out. Seemsl like there is a long ping you insert into a hole and screw the center off but I can't remember if it has a cup center under it. I don't think so.

Re: bottom of bowl question

Ron in Drums PA

>Can't you use a live center in the tail stock to center the bowl on the chuck before you lock it down?

Re: bottom of bowl question

John K Jordan

>>So what does a person do to finish off

>the bottom of a larger bowl...foot or no foot??

I use the jumbo Cole jaws, but I don't know the maximum diameter. I saw where someone made plywood extensions for the jumbo jaws which would be easy enough to do. I want to make some from aluminum.

I've seen several people make a kind of chuck from a disk of plywood mounted on a face plate. Fasten some means of fastening the bowl such as small blocks of wood cut with one edge inclined to grip the bowl or simple blocks just to keep it from sliding sideways. A friend of mine used this method and taped the bowl to the backplate with strapping tape - very strong. However, I'm sure other tape would work. He also has held bowls with double sided tape but I'd only try that for something with a flat rim.

I saw another design where the bowl was held between a flat backing plate and a ring of MDF. The ring was secured to the backing plate with several carriage bolts. This would be VERY secure. You could make a variety of ring sizes for different bowls.

You can also make a jam chuck from several layers of plywood and/or MDF glued up. Turn the diameter on the lathe.

Another thing I've done just before parting off the bowl from a waste block is partially part off while applying pressure to the inside of the bowl with a cloth-covered block mounted on the tailstock to keep things stable. Turn down the waste block to expose part/most of the bottom, then use a scraper to make a bit of rim on the bottom. Then part off, trim off the stub by hand, then sand. This is easier than it sounds if you sand with a 2" disk in a power sander.

Another method is to part off the bowl bottom from the waste block then use a power sander to sand a concave bottom. This is not as nice as some rim or ring decoration, but it can look kind of nice. The concave bottom keeps the bowl from rocking on a flat surface.

I have another idea I haven't seen done anywhere but I want to try it first myself! I'll post a picture in a month or so.

JKJ in East TN

Re: bottom of bowl question

DWFII

>Ron,

If you mean while working with the Longworth chuck...well, I tried that. But the buttons are so firm that it still won't let the body of the bowl move sideways so that you might "force" it to center. I use a light coloured grease pencil and I hold it briefly against the side of the bowl and then check to see where it's "high." I know the longworth is out of true. It has a screw that holds the outer disk of wood to the back disk. That screw, despite being placed through a previously drilled and supposedly centered hole, isn't itself turning true.

Otherwise the bowl ran perfectly true in my Axminster chuck when it was mounted via the tenon into the dovetail jaws.

I don't have enough experience or perhaps an extensive enough of a shop to do any good with these "home-made" jigs. I think you have to be pretty accurate and...well, there's something to be desired missing in that regard.

DW

In the High Desert of Central Oregon

Re: bottom of bowl question *LINK*

MikeinCapeMay

>Good answers. You can do this as well, see the link:

BTW I also have the Axminster and like it.

Oh yeah, do a search of the BP or WC articls and you'll find one by Mark Kauder for building cole jaws that will work too.


Bowl jig

Re: bottom of bowl question

Mac

>For years before I got a vacuum system I jam chucked the bowl by doing the following:Put an unfinished bowl of smaller diameter in the chuck.True the face of it up,put a piece of router mat between it and the bowl I want to finish turn the bottom on. Bring the live center up into the existing dent in the bowl bottom,turn the lathe on low speed and use a detail gouge and parting tool to make the decorative design in the bowl bottom and then turn the waste piece down to a point ..l<...and break it off,scuff with sandpaper and your done....In fact I just did one this way 10 minutes ago instead of hooking up my vacuum chuck....works great....

Re: bottom of bowl question

Dick Hines

>I guess one day I amy have a vac system but for now I use a jam chuck. I have 2 pieces of MDF board with sheet cork glued on one side and a face plate screwed to the other. Dedicate a face plate to the boards. If you take them off they may not trun up when you replace the face plate.

After I have finished the bowl all but the bottom I use the jam chuck. I bring up the tail stock and center it in the hole I left on the tennon that was in my chuck. YOu can use a cup center but I feel better knowing I have something in the tennon. Then I just turn the foot and work the tennon down to a small nub. Don't try to turn the nub all the way off. May have to chase bowl around the shop. When you get the nub down small enough all you have to do is tap it and it will fall off. Then just sand.

Re: bottom of bowl question *LINK*

Paul Porter in Phoenix, AZ

>I use a jam chuck (a round board held in my chuck) and masking tape. I have several sizes. Turn a grove in the board to fit the rim of the bowl. Protect the rim so how, I use thin high density foam from W-M. Push your tail stock with the live center on the bottom your bowl up against the jam chuck. Rotate the whole thing to make sure you are on center. Rap masking tape across the bowl and jam chuck as tight as you can. Use good tape and use a lot of tape (it's cheap compared to loosing a bowl). Keep the live center against the bowl and turn away the tenon until you have a little nub. Pull the tail stock away, brake or cut of the nub, finish turning and sand. Carefully take the tape off and you are ready to apply the finish.

This is the low tech way to go if you don't have the afore mentioned equipment.

Hope this helps.

~Paul


my web site (I sware I'll update it soon)

bottom of bowl

DWFII

>Thanks everyone...I got some ideas. I'll give some of them a shot.

When you come right down to it even a hobby turner...such as myself...really needs a larger lathe--like a Stubby--and another $5k for tools and accessories.

Then I wouldn't have these problems :D

DW

In the High Desert of Central Oregon

Re: bottom of bowl question

Chris Wenger

>The simplicity of a piece of plywood with a groove cut to fit the rim diameter of the bowl is what I used until I got my Cole Jaws. Strapping Tape a must! Use plenty! I never had a bowl take a flying break for freedom. And it gave unimpaired access to the bottom for a fine finish.

Re: bottom of bowl question

GaryG in MD

>Paul,

I certainly respect both your experience and the need for safety, but I'm curious just the same. If you have the bowl rim fitted into a groove in the chucking board (to center it and hold it laterally) and the tailstock live center brought up tight, why do you need all the tape? Without ever having done it (!) it would seem to me like it would already be fairly secure. (And masking tape isn't known for its strength -- but packing tape certainly is.) Please tell me what I am missing -- as I'll be doing something like this soon. BTW, your SW hollow forms are nothing short of gorgeous. TIA, Gary

Re: bottom of bowl question

Paul Porter in Phoenix, AZ

>The tape is to hold the bowl on the jam chuck for sanding after you move the tail stock out of the way. I wouldn't take a heavy cut with just masking tape holding the bowl. Reenforced tape would probably work better that masking tape, but is a lot more expensive.