Removing the Evidence

[Jack Tyree]

I recently watched a well known turner's demonstration video on you tube. He stated during his demonstration that one of the things that made a piece look amateurish or poorly executed was leaving evidence of how the piece was held while turned, or done.
I am a somewhat new turner with no "formal" training classes or schooling. I use a Oneway 12/24 and a Talon chuck to turn bowls. I have always left the tenon/foot or recess on the bottom and thought nothing of it. There are usually not much in the way of marks except the small lines where the contact is. Until I watched the video. Now I'm not so sure anymore. Is this really that tacky? What is the preferred method used for reversing a bowl to remove the foot or recess?
Thanks in advance for your ideas.

[Jeff Nicol]

Jack, There are many ways to turn the bowl around and rechuck it. The old stand by is the jam chuck to hold the bowl between centers and finish the bottom then take away the tail stock and finish off the little nub left, or just carve and sand it away. Then you could use a friction drive to do the same thing. You could use the big cole type jaws to hold the bowl and use the tailstock again until you are almost done then finish the little nub again in the same manner as stated above. You could set up a vacuum system and use vacuum chucks to do the same thing just with vacuum instead of friction. There is also the donut style chuck that some people use, that does the job too. So like I said there are many!

Jam Chuck
Friction drive
Cole jaws
Vacuum chuck
Donut chuck
Longworth chuck

Good luck and do some research on each one and you will figure out the one that works best for you. Most of the time cost is the only thing that is different in the end.

Jeff

[Steve Schlumpf]

Jack - to me it is just a natural progression when starting out turning. When I turned my first bowls I was so happy to finally get it off the lathe in one piece that I didn't dare try to figure out a way to remove the tenon or recess. After a little more turning time - and less attachment to the completed bowls - I learned that you can use a jam chuck, Cole Jaws for the Talon chuck, a Donut chuck, a Longworth chuck and also a vacuum chuck.

There is lots of info on this forum on all these methods and even a current thread about jam chucks. Read up a little on them and figure out which method you would like to try and we will help you get there.

Ask as many questions as you can and remember - most of us here are self taught - so have figured out many different ways to accomplish the same tasks!

[Bob Hamilton]

Hi, Jack:
There are quite a few ways to reverse the piece for removing the tenon. Most of them involve using the tailstock to support the piece while removing all but the small stub where the tailstock point is and then removing the piece from the lathe, sawing off the stub and paring it flush with a bench chisel.

Perhaps the easiest is a jam chuck or friction drive. Nomenclature is a bit iffy, since different people call different things by the same name. The simplest friction drive is just a stub of wood mounted on the headstock in some fashion like on a faceplate or held in a chuck. The face of the stub is very roughly shaped to seat against the inside bottom of the bowl, like this:

http://bobhamswwing.com/Articles/No%20Chuck%20Bowl/No%20chuck%20bowl/100_8981-640.jpg

For this type of mounting where the drive is going to be against a surface of the bowl which is already finished it is a good idea to pad the face of the stub with a folded up shop towel or a piece of foam rubber or something before slipping the bowl over it and using the tailstock to apply pressure against the friction drive. In this picture you can see the corners of the folded shop towel I used peeking out around the rim of the bowl:

http://bobhamswwing.com/Articles/No%20Chuck%20Bowl/No%20chuck%20bowl/100_8984-640.jpg

You can turn away most of the tenon and reduce the section where the tailstock is by tapering it:

http://bobhamswwing.com/Articles/No%20Chuck%20Bowl/No%20chuck%20bowl/100_8993-640.jpg

Once you have sanded and detailed the base to your satisfaction you would remove it from the lathe and saw off the little stub and pare it flush.

Another sort of friction drive is just a large disk with a foam facing glued to it that the entire rim of the bowl can seat against. The rest of the procedure remains the same.

http://bobhamswwing.com/Articles/No%20Chuck%20Bowl/No%20chuck%20bowl/100_8994-640.jpg

http://bobhamswwing.com/Articles/No%20Chuck%20Bowl/No%20chuck%20bowl/100_8998-640.jpg

A more refined option is a donut chuck, which is a large disk for the rim of the bowl to seat against and a second disk with a hole cut in the center. The workpiece is sandwiched between the two disks with its base protruding through the hole so it is available to be completely worked without the tailstock getting in the way. Carriage bolts and wingnuts at the rims of the two disks hold them in alignment and exert pressure to keep the workpiece from moving. I don't have a picture of a donut chuck handy, but a google search will turn up scads of them.

The ultimate method is to use a vacuum chuck. The bowl is held against the chuck by air pressure when a vacuum is drawn through the headstock spindle from inside the chuck. The big pink disk in the previous picture is actually one of my vacuum chucks. The rim of the bowl seals against the foam facing of the disk and a vacuum is drawn through the hole in the middle, allowing the entire outside surface of the bowl to be worked.

Good Luck!
Bob

[Judy Kingery]

Hi Jack,

You've got great answers - one other variable not mentioned so far might be when you leave a foot on purpose; such as perhaps carve say three little ball feet out of the tenon and remove the rest. I've done it several ways: remove the tenon entirely, or leave a foot on purpose, or accidently break an intended foot off the tenon so take it down to a flat bottom with rings. It's fun to explore a number of ways of doing it and the guys have given you great suggestions!

Jude

[Jack Tyree]

Thanks for the input. I have a set of the small flat jaws for the Talon chuck, and am going to try to turn a set of donut jaws for them. Would yellow pine be strong enough? I have some 2 X 12 pieces left over I could use.
I just couldn't see in my mind's eye how you could use them without losing your true center and making the bottom look worse than with the recess. I would love to have a vacuum chuck set up and that is high on my wish list, but they are very expensive and are down the road a ways.

[Wilbur Pan]

I recently watched a well known turner's demonstration video on you tube. He stated during his demonstration that one of the things that made a piece look amateurish or poorly executed was leaving evidence of how the piece was held while turned, or done.

I always thought this was an odd train of thought. If I look at the bottom of a bowl, and don't find a dovetailed recess, then I immediately know the turner reversed the bowl and turned away the tenon or recess he/she used to hold the bowl. So there's no secrets there. ;)

For me, I use a face plate that I've attached a piece of scrap wood to, turn a shallow recess to fit the rim of the bowl, and use a ton of blue painter's tape to hold the bowl on (actually, 8 long strips arranged so that they overlap to form an octagon around the bottom of the bowl), and a little bit of tailstock support if needed. Then I turn away my tenon.

[Jack Tyree]

Bob, I watched your new videos this morning and I liked your donut chuck setup and thought about making one tomorrow, but now that I see your other idea with the foam, I think I like that idea better. I can see how you would keep your center better without making a mess of things. It also looks like you could get a decent finish on most of the bottom before removing the nub. Thanks again for the inspirations, and also a great tutorial video.

[Bob Hamilton]

Jack, the easiest way to get it re-centered is to plan ahead and make a dimple in the bottom of the tenon with your tail center before you ever turn it around to hollow out the bowl.

A donut chuck is a different animal than the kind of custom wooden jaws mounted on flat jaws that I was using in my video. The custom jaws would work okay for small to medium size bowls but you have to be realistic in your expectations. Wood is not strong enough to allow too much overhang from the flat jaws. I wouldn't go any more than about 10" in diameter for wooden jaws and then keep the speed low to minimize the forces acting on them.

I have noticed just lately that some people are beginning to refer to Cole jaws as flat jaws, so just to be sure we are talking about the same things, these are what I call flat jaws:

http://www.oneway.ca/chucks/accessories/flat_jaws.htm

Nova calls their large jaws Cole jaws and Oneway calls theirs Jumbo jaws:

http://www.oneway.ca/chucks/accessories/jumbo_jaws.htm

The Cole or Jumbo jaws are purpose made for gripping bowls by their rim for working the bottoms.

Take care

Bob

[Thom Sturgill]

Since you seem concerned about aligning the piece when you reverse it, I would like to make a comment. If you used a screw chuck to start with, then when you turn your tenon, before you unmount the piece, make a small hole in the center of the tenon. That will line up the tailstock when you reverse after doing the inside. If you start between centers, you will already have a spot to center with.

More expensively, they sell morris tapers that will screw into the back of the chuck so that you spin the chuck off the headstock, insert the MT and mount it on tailstock. Then clamp the piece down and remove the chuck. I found this works well to center on the vacuum chuck.

[Jack Tyree]

OK, now I understand. I saw the donut chuck and that's not what I was thinking about making (at least not for reversing bowls). I saw one used for segmented HF's and I think they are the berries for them and intend to try that when I get a little more experience. What I was going to do was use a piece of 2 X 12 cut into quarters and installed on the Oneway flat jaws I have, and then turn in the appropriate size recess to hold the rim of the bowl. Only problem was that it involved so much assembly and disassembly to install the jaws and then install the wood and visa versa, if you get my drift.
I think the a flat disc on an extra face plate with the foam makes the most sense for the size bowls I usually make. It seems like the least amount of fussing.

[Toney Robertson]

I recently watched a well known turner's demonstration video on you tube. He stated during his demonstration that one of the things that made a piece look amateurish or poorly executed was leaving evidence of how the piece was held while turned, or done.

I have heard the same thing but I am like you in that I don't get it. Unless you put a sign on the bottom telling how you chucked it with arrows pointing to the recess/tenon 99% of the people are not going to have a CLUE as to how it was done.

I almost always use a recess and most of the time it is no more than 1/8" of an inch deep so the dovetail is not obvious especially to the untrained eye. Therefore, almost all of the people are going to think that the recess is a design element NOT a way to hold it on the lathe. As a matter of fact, most people would have a hard time believing that such a small recess is how it was mounted.

IMO turning off the recess is like turning thin, more for the sake of other turners than for the buying public.

Just my .02 and that is about all it is worth!!! :D

Toney

[Jack Tyree]

Toney, I think you are right and I like your opinion. My wife thinks I'm OC for even worrying about it, she say's they look fine, and they don't wobble like my tables. Thanks for the opinion and your right on about the thin thing too.

[Ken Fitzgerald]

Jack,

Recesses....I wouldn't worry about.

Tenons on the other hand, IMHO, should be removed but that is just my personal taste and opinion.

On my turnings HFs and bowls I use a donut chuck.

[Reed Gray]

I am another who uses a recess and doesn't turn it off. My bowls are warped and almost none of them will sit flat. No one seems to mind. They say, "Oh! it is so organic!" For me it is an extra production step, and would add to cost, and I couldn't sell them for any more money. If put side by side, the cheaper ones will sell first (color, figure size and shape being similar). The people who are most interested in how the bottom was turned off, are other turners, and there are only a limited number of options. No mysteries. There are no marks in my recesses because when turning, the recess matches the chuck jaws almost exactly. A little lemon juice will remove any metal stains. For sanding out the bowls, I use extended small jaws because the recess will have moved enough that the jaws used the first time won't work. No marks again, because very little pressure is needed to sand. You can decorate the inside of the recess if you wish, but for me, I just sand it (power sander and small mandril) and apply oil. I would turn a tenon off.
robo hippy

[Robert McGowen]

I guess it comes down to personal taste. I would have to agree with the video, as I always finish off the bottom of a bowl or vase. I think that it just looks "finished". Once I built the ole' Schlumpf Special vacuum chuck setup, it is so easy to do, I just HAVE to do it! :D

[ROY DICK]

I use the recee and wrap the jaws with blue masking tape. No need to tighten the chuck very much.

Roy

[Roger Wilson]

As for tenons, if you leave a solid tenon, it isn't as elegant as it could be.

If you remove the center, leaving a ring you've got a perfectly acceptable foot for the bowl. It raises the bowl up a little off the surface.

You can also carve away all but three mini-feet on that ring tenon and that too is fine.

It's really all an artistic judgement.

If you goto AAW's gallery and look at all the bowls you'll see lots of them are deliberately left with tenons of varying heights.

[Daniel Winsor]

If you do decide to turn off the tenon or recess, don't leave the bottom of the bowl flat. As the wood moves, your bowl will start to wobble when sitting down. Make an ever so slightly concave surface on the bottom of the bowl and then you'll have a stable bowl, as long as you didn't turn it green. Even if the wood moves a little, it will still sit flat. I've found that properly dried wood doesn't move enough after turning to make it wobble if I've made that concave recess.

Dan

[Kaptan J.W. Meek]

If you do decide to turn off the tenon or recess, don't leave the bottom of the bowl flat. Make an ever so slightly concave surface on the bottom of the bowl and then you'll have a stable bowl,... I've found that properly dried wood doesn't move enough after turning to make it wobble if I've made that concave recess.

EXACTLY! you just beat me to it.. The first book on turning I read was by Richard Raffin (spelling?) It was in his book, "The best pieces show no evidence of how they were ever mounted on the lathe" ... I really took this to heart. It bothers me just as much as anyone else.. My FATHER says I'm OC because it bothers me. I use a friction drive now, but I'm working on a donut chuck.

[lynn smith]

I like having the foot that is created by leaving the tenon and smoothing out the bottom, it also makes a nice place for the signature.
i still need to finish sanding the bottoms on these two bowls.