Rechucking bowls

[Don Meyer]

I am basicly a new bie to bowl turning. As of now I have been making a recess in the bottom of my bowls for the chuck jaws to expand into. I am asking for suggestions on how to rechuck the bowls if I start to make tenons for the chuck to hold onto.

 

[Joe Greiner]

Lock four turners in a room without access to toilet facilities, and you'll still get at least 8 ways to chuck and re-chuck bowls.

The simplest way I've found for forming tenons is to first turn the blank between centers, turning the tenon at the tailstock end.

But, which re-chucking are you concerned about? To turn the inside? Or to finish the bottom?

 

[KurtB]

Rechucking

Don, assuming you have turned the outside of the bowl, turned it around and chucked it to turn the inside, you now need to rechuck it to finish the bottom. Right?

A waste block in the chuck with a recess for the bowl edge and the tailstock brought up to secure would probably be your first place to start. Or, you can turn a waste block that matches the inside of the bowl. You could also put a piece of mouse pad over the chuck jaws and place the bowl against the pad and bring up the tailstock. These methods require you to turn the bottom down to a small cone point, which you then cut off.

An alternate method, depending on the shape of your bowl is to use cole jaws with the small rubber bumpers to hold the piece, either on the outside of the bowl or on the inside. This has the advantage of allowing you to work on the bottom without the tailstock in the way. Another method is to use a vacuum chuck, which would also allow complete access to the bottom. Hope this answers your question.🙂

 

[MichaelMouse]

You're doing it right, why change?😀

I like an innie, too. Actually two innies. I use a pin chuck, or pin jaws on a smaller piece, for initial mounting and turn between centers for round and better balance. I then then snug the jaws and make the mortise. When I reverse to mount, I use the Forstner hole for centering and hold on the tapered nose of my live center. Leaving the pillar in means I can drop the Forstner down to make it circular after the piece dries. I mount on the pin, true and round the mortise, same as I did for green wood. Nice, because the holes get smaller when drying, and you just remove enough wood to get back to your optimum grip size.

http://i35.photobucket.com/albums/d160/GoodOnesGone/Method-One.jpg
http://i35.photobucket.com/albums/d160/GoodOnesGone/Method-Two.jpg
http://i35.photobucket.com/albums/d160/GoodOnesGone/Method-3.jpg

Those using tenons have to remember to cut them over the optimum size for the jaws, because they will shrink. Leave a nice center-finding dimple for later and, if you think of it, leave the pillar on the opposite end. Then you can round your counterbore, mount between centers and turn easily after it dries.

If you use a coring tool or don't want the safety and simplicity of a pillar, you can shim your open bowl face down on the drillpress table and use a hole saw to cut your tenon round. Make sure the center bit is minimally exposed to avoid surprises.

Or any of the other suggestions.

 

[Don Meyer]

Thanks

Thanks guys for taking the time to reply to my questions. I am basically interested in turning off the tenon on the bottom of the bowl after forming the inside of the bowl. You have given me some great iddeas to mull over while I practice. Thanks again for your help.

 

[Joe Greiner]

I skipped the Cole jaws, and went directly to a couple DIY Longworth chucks for bottom finishing. There are tons of hits on the Internet for plans and procedures. Google is your friend.

But for a while at first, I used a plywood disk mounted on a faceplate. Turn a groove to mate with the bowl rim. Mount the bowl with tailstock assist for centering, and wrap tape (duct, masking, filament strongest) across the exterior reaching the back of the disk. Release the tailstock just before completion, or sooner as you gain confidence. Re-cut grooves when needed, and replace the disks eventually. There's a longer discussion in "Lathes and Turning Techniques - The Best of Fine Fine Woodworking," page 111, by Betty Scarpino. ISBN 1-56158-021-X

I still use the tape on the Longworths for insurance. One orbiting satellite is quite enough.

 

[hughie]

The simplest way I've found for forming tenons is to first turn the blank between centers, turning the tenon at the tailstock end.

Thats pretty well the way I go about it, screw chuck and tailstock live centre.Turning the tenon at the tailstock end and finish the base off at the end with my Longworth chuck

 

[Bill Travelstead]

...how to rechuck the bowls if I start to make tenons for the chuck to hold onto.

A donut chuck is another option and easier to make then the longworth. Bill Grumbine shows one in use on one of his DVD's.

Here's two articles that show how:

http://syzygypens.com/blog/2009/02/22/donut-chuck/

http://www.nealaddy.org/node/42

Here is a pdf by John Lucas that shows ALL the options:

http://www.cumberlandwoodturners.com/tips/Methods%20and%20Jigs%20for%20Reverse%20Turning%20Bowls.pdf

 

[john lucas]

Thanks Bill. I was going to post the directions to that PDF. I tried to cover all the different ways of reverse turning a bowl.

 

[jongibbs]

I know that Joe said that there were as many methods as there are turners, but did anyone mention wooden chuck jaws?

I have made a donut chuck which I find is great for off-centre rechucking, but I mostly use wooden jaws in my Axminster chuck.

I make my wood jaws from a thick MDF sandwich with as big a diameter as I think I'll need. They're usually 3 x 18mm sheets glued together with PU glue. I can then easily resize them if necessary with a small 1/4" step to fit either inside or outside the bowl rim I'm working on.

I hope this helps
Jon Gibbs

 

[waltben]

Although I sometimes use bowl jaws to finish a bottom, I almost exclusively use vacuum chucking. I've four different size drum-like vacuum chucks and have only very seldom had a piece that I couldn't use one of them on.

 

[Odie]

Although I sometimes use bowl jaws to finish a bottom, I almost exclusively use vacuum chucking. I've four different size drum-like vacuum chucks and have only very seldom had a piece that I couldn't use one of them on.

Waltben.......

Isn't it a bit difficult getting the bottom exactly "square" with the rest of the turning, when using a vacuum chuck?

OOC

 

[john lucas]

There are several ways to chuck a bowl using a vacuum chuck and keep it true. If I started the bowl between centers there will be a little centering nub. I can just bring up the tailstock and push the bowl onto the vacuum chuck and it's aligned.
If I had to remove the centering nub or started the work some other way I have 2 ways to center it using the tailstock. One is a #2 morse taper with my lathe spindle threads on the other end. This is sold by www.bestwoodtools.com. It fits in the tailstock and you screw the faceplate or chuck onto this with the bowl still in place. Push it up to the vacuum chuck and it's aligned. Turn on the vacuum, remove the chuck and your ready to go.
The other method is the same but uses the Oneway live tailcenter or the Powermatic/jet copy of the same. Buy the Oneway threaded adaptor that fits on the tailscenter and has your lathes threads. This works the same way as the bestwoodtools center except the center is live. I still remove it before actually turning. The only downside to this is you have to find the little rod that locks the live center in place to be able to screw the adaptor on or to install or remove the chuck.
I believe I have those two adaptors pictured in the PDF listed on our club website.

 

[waltben]

I start with a relatively low vacuum (around 5 inches of mercury by the gauge) and bump the piece with my hand to get it centered. This seldom takes more than a few minutes unless the wood has moved and I've got to find a compromise spot. When it's where I want it, I close the bypass valve and finish turning - usually starting with a 3/8" bowl gouge or scraper and light cuts. My Surplus Center Gast pump will pull about 20", and that's more than enough to keep something in place.

 

[Odie]

I do not have, nor have ever had the opportunity to use or observe a vacuum chuck being used.......so, all my thoughts on it are theoretical. I do use the OW mega-jumbo jaws, and they work well for me. The only drawback to the MJJs is they sometimes require me to design bowls that are easily adaptable to that method of holding the bowl for turning the foot. Most of the time, this really doesn't present any real problem for me, but occasionally it does.

With the four slots for variable gripping, many times I can get away with turning the foot on a natural edge bowl......but, there is a certain amount of design limitation for doing this.......it's do-able, but I can sure see the advantage of a vacuum chuck for this application. (I have the plans for making the "Grumbine chuck", but haven't gotten around to doing that yet!)

If I had to remove the centering nub or started the work some other way I have 2 ways to center it using the tailstock. One is a #2 morse taper with my lathe spindle threads on the other end. This is sold by www.bestwoodtools.com. It fits in the tailstock and you screw the faceplate or chuck onto this with the bowl still in place. Push it up to the vacuum chuck and it's aligned. Turn on the vacuum, remove the chuck and your ready to go.


The other method is the same but uses the Oneway live tailcenter or the Powermatic/jet copy of the same. Buy the Oneway threaded adaptor that fits on the tailscenter and has your lathes threads. This works the same way as the bestwoodtools center except the center is live. I still remove it before actually turning. The only downside to this is you have to find the little rod that locks the live center in place to be able to screw the adaptor on or to install or remove the chuck.

John......

Thanks for your input. These two methods you mention ,using a specialized adaptor that has your spindle threads plus #2 morse taper in the tail stock hadn't occurred to me. Thanks for letting me know about that. I wonder if those adaptors might be usable for the Grumbine chuck method? At first thought, it might require chucking and unchucking while one section of the Grumbine chuck is in place......but seems like it could be done.......?

I start with a relatively low vacuum (around 5 inches of mercury by the gauge) and bump the piece with my hand to get it centered. This seldom takes more than a few minutes unless the wood has moved and I've got to find a compromise spot. When it's where I want it, I close the bypass valve and finish turning - usually starting with a 3/8" bowl gouge or scraper and light cuts. My Surplus Center Gast pump will pull about 20", and that's more than enough to keep something in place.

Waltben......

This is the way I had imagined it to be.....pretty much a method of trial and error, until you get it right. I'll bet it can be frustrating at times.......but, I suppose it all depends on how close the match is to your expectations.......or requirements.

Thanks for the input, gentlemen......

OOC

 

[waltben]

This is the way I had imagined it to be.....pretty much a method of trial and error, until you get it right. I'll bet it can be frustrating at times.......but, I suppose it all depends on how close the match is to your expectations.......or requirements.
OOC

I believe you think this is much harder than it actually is. How about trying to turn a bottom with jaws after the rim has warped so that no matter what you do it'll be off axis? I've seen that happen to others several times, but as I posted, I can find a compromise spot with a vacuum rig that you can't with bowl jaws. Without that situation, I've still not had to spend more than a few minutes centering a piece - certainly less time than changing jaw sets on a chuck.

 

[john lucas]

I do a fair number of bowl turnings at events around town. On those days I don't carry all the stuff with me. Just a chuck, a rubber sink stopper, and a live center with a longer point. Once I've turned the bowl I put the rubber sink stopper over the chuck and then bring the tailcenter up to the point that was left after turning between centers. Then I turn the bottom using mostly the bowl gouge.
I have special tool I made that has a crook to the left. It's like a bent ornament hollowing tool except the tip is square and bent to the left. this lets me clean up the shape of the inside of the foot.
Then I take a detail spindle gouge and cut most of the little tenon that's left until I'm too nervous about it breaking off. I slow the lathe down, reduce the pressure on the tailcenter and then push on the bottom of the bowl with the spindle gouge bevel abd very slowly advance the tool until I cut off the tenon.

 

[Joe Greiner]

I believe you think this is much harder than it actually is. How about trying to turn a bottom with jaws after the rim has warped so that no matter what you do it'll be off axis? I've seen that happen to others several times, but as I posted, I can find a compromise spot with a vacuum rig that you can't with bowl jaws. Without that situation, I've still not had to spend more than a few minutes centering a piece - certainly less time than changing jaw sets on a chuck.

Amen to that. A few minutes of micro-adjustment with a precision rubber mallet should be sufficient.

Also, have a squint here: http://www.aawforum.org/vbforum/showthread.php?t=5668&highlight=bottom

 

[MichaelMouse]

I just avoid all of the above by leaving the mortise, suitably sanded, in the finished piece. As I said originally, you're already doing things right, just do them to completion. http://i35.photobucket.com/albums/d160/GoodOnesGone/Fudge-Dish.jpg Or similar.

 

[john lucas]

But if you don't want a mortise but would rather have a thin rim for a foot or perhaps carve away part of the foot so you have 3 or 4 seperate feet, then you have to do it our way.
Not saying a mortise is bad, I do that on almost all of my platters and occasionally on a bowl. It's just nice to have other options.

 

[Odie]

I believe you think this is much harder than it actually is. How about trying to turn a bottom with jaws after the rim has warped so that no matter what you do it'll be off axis? I've seen that happen to others several times, but as I posted, I can find a compromise spot with a vacuum rig that you can't with bowl jaws. Without that situation, I've still not had to spend more than a few minutes centering a piece - certainly less time than changing jaw sets on a chuck.

You could be right, waltben.....never tried a vacuum chuck, so at this point, my imagination is my only way of judging how it would be.......

....not sure a vacuum chuck is a method I will wish to pursue, though.

OOC

 

[Dave Ogren]

Don,

I am probably newer than you are (51 bowls to date). Why would you want to change what you are doing ? When I started I read a lot of posts and decided what I was going to do. My lathe does not have a tailstock so everything goes onto a faceplate, I have a 3",8" and 10". The 8" is the most commonly one used. I turn the outside then the foot, cut a recess 2 5/8" and the O.D. is done. Put the chuck on the machine, chuck in the recess, and hollow out the interior to less than 5% wall thickness of the dia. Dry, Sand and Finish. It seems to me that this saves a lot of time etc. Am I missing something ?? Thanks for all your help. Keep up the great threads.

Dave

 

[MichaelMouse]

Don, it's called "style," or should be. You've got yours, and the fuss and fancy folks have theirs. Wouldn't let it worry me a lot. Haven't ever had someone other than a turner mention the bottom as a part of the bowl. Don't see a lot of it unless you spill the contents, after all.

Sort of like turning thin, it's something turners think shows a level of skill, when it mostly shows a lack of utility to the prospective buyer.

 

[Malcolm Smith]

Older turned bowls often had a very plain bottom. Clearly a lot of them were cut flat with a saw. The newer lathes, chucks etc make it much easier to put a fancy bottom on a bowl. It's really a personal choice which way you go,

Malcolm Smith.

 

[waltben]

About bottoms: I turn decor pieces, not museum pieces and not salad bowls. They're of high figured woods and usually of different forms, but I very, very seldom try to show off my turning abilities on the 'top' part. I began getting creative on the bottom or foot, when I felt I should be giving a buyer something extra. What reinforced my thinking was when I attended Totally Turning in Albany, NY a few years ago, and Stewart Batty lifted up someone else's piece and commented on how he liked to see a 'surprise' underneath a clean form. That pushed me into doing what I attempt to do today.

 

[Jake Debski]

About bottoms:............................................... What reinforced my thinking was when I attended Totally Turning in Albany, NY a few years ago, and Stewart Batty lifted up someone else's piece and commented on how he liked to see a 'surprise' underneath a clean form. That pushed me into doing what I attempt to do today.

Walt, I recently turned a small bowl from yellow heart, attractive color but otherwise bland. After adding a textured blackwood disk in a recess cut in the tennon I thought it was quite pleasing, to turnover this bowl and find the contrasting bottom. Unfortunately almost to a man/woman, at the show and tell table of our monthly meeting, the comment was "went to thin on the bottom eh."🙁 I plan on continuing the practice because I like the result. 😀

 

[Gretch Flo]

Thin bottoms.

Like I did last week!!!!!!! Now I know --I did it on purpose!!!!!😉 Gretch

 

[Vaughn]

Personally, I prefer a simple concave bottom, but I don't really like the looks of a sharp-edged dovetail recess on the bottom of a finished bowl. Especially if the jaw marks are still visible. The times I've used a recess, I've turned most of it away when finishing the piece. But that's just personal preference.

...Sort of like turning thin, it's something turners think shows a level of skill, when it mostly shows a lack of utility to the prospective buyer.

I don't necessarily go as thin as a lot of turners, but utility is about the farthest thing from my mind when I make and sell most pieces. I guess that makes me a 'fuss and fancy' folk. And for the record, I don't really care about how others perceive my skill level. It's the end result that matters, IMHO.

 

[Odie]

And for the record, I don't really care about how others perceive my skill level.

Exactly! YOU, and how you perceive your own work are the ONLY one that matters.

Whether you view Vaughn's comment as advice, philosophy, or just arrogance, he's come to a realization that anyone who wishes to make woodturning an expression of individuality and soul.......will have to understand.

I, for one, am glad to see you make that comment, Vaughn. At one time, in the distant past, I made the same comment......and there were those who didn't particularly like what I said......but, I feel they just don't understand what you do.

ooc

 

[Jake Debski]

............................. And for the record, I don't really care about how others perceive my skill level. It's the end result that matters, IMHO.

Yup! Well put.