To "tuck" or not to "tuck" - that is the question

[John Keeton]

In a thread I recently posted on a vase form, Prashun Patel inquired about "the tuck" and asked to what was the reference. It seems most folks use that term to refer to creating a slight "tightening of the curve" at the base to create the illusion of lift.

Since most all of the upright/vase forms one sees have a lower curvature that approximates a catenary or parabolic curve, and since there is a difference of preference on how to handle the base of the form, I thought it might be interesting and informative to explore the idea of "the tuck."

This image shows a catenary curve and a parabolic curve, as well as horizontal lines I have drawn in to represent possible points along those curves at which one might "truncate" the form, thereby creating the base. Obviously, the diameter of the piece affects these curves - a wider or more narrow form would produce a curve that would be somewhat different in appearance than these. But, for the purposes of this thread perhaps this image will work.

If one truncates the piece close to the tip, the curvature accelerates into a naturally formed "tuck". If it is truncated higher, there is naturally an absence of tuck. The smaller the base, the more natural "tuck" one achieves.

THE TUCK.jpg

So, to start the discussion, perhaps the following questions migh evoke some response.

Is "tucking" a design consideration for you? Do you like the look? Do you purposefully "tuck" your forms? Do you consider the mathematical or natural curvature in making that decision as to whether to tuck, or at what location? Does the anticipated diameter of the base effect your decision? Are there other considerations not stated above?

Since I have posed the questions, it is only fair I start the discussion. As I have stated previously, I do not care for an ultra small base on a vase form as I do not like the "tipsy" nature of such pieces. I do not care for a "tuck" that is imposed higher on the curve than it would naturally occur.

What say you??

[Tim Rinehart]

Good thread John. I debate this often, and feel like it is sometimes forced on a piece it doesn't fit. I am finishing up a tallish hf with a large opening, and leaving the base a nice size, though a bit smaller than opening. A tucked base didn't suit it IMO, so it's truncated catenary. I think the more important element is the whole flow of the piece, and as the catenary would indicate, some larger feet flow better truncated than forced to tuck.
Will be interesting to see others view on this also, but I agree some pieces lose safe display value if tucking results in an overly tippy form.

[steven carter]

Geez, I guess I missed the meaning of the "tuck". I thought it meant having the very bottom of the form rolled under so the edge of the form doesn't touch the sufface at the bottom edge, but slightly inside. It seems that people talk about generating a shadow line there. On my last HF Jamie Donaldson suggested it maight be an improvement. I have another that I will post soon where I tried to accomplish this. I may have to re-think this.

[Roger Chandler]

In my thinking, the base diameter of the form has to be in proportion to the width and height of the vessel.........a wide form and a tall one at that must have a stable foot, and on something like that, I like the second line from the bottom on your drawing. [the turqoise/blu-ish line]

As a part of the curve, I think a "tuck" is in order for a lot of hollow forms.........I think it gives a finish look rather than a cut off look.......

One can also reverse the tuck by going out from the form with a flared base.......it serves to add stability and is in some instances a design feature that enhances the look of the form.........[a footed vase] and both appeal to me. I agree with you John, that too high on the form just throws everything off......the golden mean, [makes the shoulder too low] and is less pleasing to the eye.

My $0.02 for what it's worth!

[Faust M. Ruggiero]

John,
A line drawing can seem so hard and unforgiving. It seems any curve when drawn to completion will find a bottom. However, we all know no vase will stand on that natural meeting of the curves. To be a purist, you have to suspend a hollow form made to a perfect parabola from a stand like the one you posted a week or so ago. The dilemma is how do we terminate the curves to form a base that works for the intended use of the form we are creating while not betraying our artistic senses. Cutting away the bottom of the form is one way but produces a drastic halt to the curves that some may find detracting from the form. Personally, I avoid the temptation to make a hollow form that you have to glue to a shelf to assure it's existence. I think the way to find a tuck that works may be with a thin chain. I often hang a thin chain on a wall in the shop and widen or narrow it to form a shape I like. Of course, the termination at the base ranges from a point to a blunt curve. Neither will support the piece. To see the shape of the base with a tuck that flows, I pick up the bottom of the chain and raise it a bit. That makes a tuck naturally. Of course, I can adjust the size of the bottom by how far I raise the chain. Then pick a spot and draw a line at the lowest point of the curve to represent the base. I try not to follow too many "rules" about base size. It has to look good to my eye and fit the rest of the form. I use a fragile chain so it allows the small radius required for the tuck.
For me, the tough part is making the finished form match what I have drawn.
faust

[alex carey]

"thats one tuck and one no-tuck"

[Jim Burr]

I'd agree that a .275" base on a 6" form is kinda goofy. On the other hand, the "playdoh-slammed-on-a-counter as a base really takes away from the flow of the curve over all.

[David DeCristoforo]

Gotta agree with Alex... sounds like a Seinfeld episode to me! I'm gonna stick my neck out here and say "it depends". I have limited experience with hollow forms but the ones I like best seem to have at least a softening of the edge at the bottom. Forms that are squared off at the bottom can look truncated, especially if the bottom is fairly wide in relation to the form's height. But there are forms that look better if they are "planted" firmly on the display surface. Hence the "it depends". I have seen forms that have such a heavily "tucked" bottom edge that they look like they will roll over at any moment. The "trend" at this point is to roll the bottom edge. If you look compare Andy DiPetro's forms with those done by Keith Burns, you will have clear illustrations of both "schools of thought". Andy's forms are always heavily rolled at the bottom while Keith's are more "squarish". But it would be hard to argue with either one.

[Dennis Ford]

My preference is to continue the "natural" curve and not "tuck".

[Thom Sturgill]

My tendency is to truncate, and if I feel the form needs some lift, to add a foot in the form of a bead, or rarely to invert the curve and flair it out a little bit. On the other hand, I do not know that my curves are either parabolic or catenary but are what is allowed by the length and width of the timber, and what 'feels' right.

[Rich Greinert]

My preference is to continue the "natural" curve and not "tuck".

+1, this is my preferred method.

[Mike Golka]

Geeeez, the only tucking I'm going to be doing for the 6+ weeks is myself into bed. God I miss my lathe! I think as others have stated it really depends on the piece. I personally try for what looks good to me.

[Deane Allinson]

I don't think about it too much. I look at how the wood pattens start to develop as I remove wood, both inside and out and find a pleasing curve that complements the pattern if there is one. I remove stuff until I see something that I like. I have only been turning a little over a year and have never had any turning go as planned. I react to what I see and what happens. I don't know what a natural curve is in nature, maybe in orbits but that is a little over my head.
Deane

[Hayes Rutherford]

John, I like the way you "take the bull by the horns" when it comes to discussing something and get right to the facts. It wasn't long ago that perfectly acceptable forms could look like they grew right out of the table or even have a slight reverse curve at the base. The internet is at least partly responsible for or has influenced the look of forms of the turners who take part and if the "jury" says your piece is awesome, you might continue in that direction. It wouldn't be hard to determine when the tucked under look started, it surly didn't start during the Ming Dynasty but it has arrived.

So I would say in my own work i have made an effort to avoid ending the bottom at a hard line and don't know if the pictured forms are really tucked or not. These are pretty plain maple or birch, now dry and waiting further attention. One thing is you can't really tell how big the base is so no one can say your base is supposed to be smaller than the opening.

[Jim Underwood]

I think I'd rather have a truncated bottom or.... the dreaded foot... or even a bevel, than to see the kind of rolled under bottom that seems to be the trend right now (as Steven Carter at #3 defined it). In my opinion, the rolled under bottom doesn't make it "float", it makes an otherwise decent curve look bad. If you're going to tuck the bottom under, then the curve should be continuous, and not a change in direction...