two point vs three point bowl steady......

[Odie]

I have a Oneway bowl steady, and have been happy with it. It works, and absolutely does reduce bowl oscillations, or vibrations during turning.

Many of my bowls are thin wall, a structural condition that contributes significantly to oscillation, and I've been asking myself if my attempts to stabilize the revolving bowl could be better.....?

Now.....here's my initial thinking on this: The Oneway stabilizes the bowl from two points, and since they are not opposed geometrically, the pressure is generally from one side of the bowl, to the other.

There are several three-point bowl steady rests on the market, and if the three points are separated by 120 degrees each........well, wouldn't the result mean that the pressure applied to the bowl would be equally distributed from the outside to the center?

If that is so, then couldn't it theoretically be suggested that a three point set-up would give an added stabilizing effect, over a two point jig?

It is obvious that there is significantly less "free space" with the three point, over the two point rest.......

For those of you who have "hands on" experience with both methods, I'd be especially interested in your evaluations........but, all comments are certainly welcome.

One additional comment/enquiry: If three wheels are better than two (and, this has not been established as yet).......then what about four, five, six wheels, etc.? Is there a point where diminishing returns, or no returns will be had at all?

Long before the current crop of bowl steadys were available to us, turners used their hands on the opposite side of the bowl wall they were removing wood. I've done this, and it works, but I have reservations about the safety aspects of using your hands/fingers in direct contact with the spinning wood......especially for thin wall. I've always had a great fear of a bowl self destructing when my hands were in contact with it. The mental image of that happening isn't very pretty at all!

ooc

 

[john lucas]

Odie When I turn thin bowls they tend to warp so a steady would not work. I turn them down a few inches at a time to final thickness. This way I never have to go back to the area that warps. Consequently vibration is not a problem. Well actually it is sometimes if the piece warps enough to set up vibration but since it's out of round I don't think a steady would work. I do occasionally steady the outside with my fingers on really thin pieces that tend to chatter.
I have only used a 3 wheel steady so I can't answer your question.

 

[Odie]

Odie When I turn thin bowls they tend to warp so a steady would not work. I turn them down a few inches at a time to final thickness. This way I never have to go back to the area that warps. Consequently vibration is not a problem. Well actually it is sometimes if the piece warps enough to set up vibration but since it's out of round I don't think a steady would work. I do occasionally steady the outside with my fingers on really thin pieces that tend to chatter.
I have only used a 3 wheel steady so I can't answer your question.

Question, John:

Is your steady intended for bowls, or a spindle steady? Brand?

As do you, I also use wood yet to be removed for support as I work my way to the bottom of the bowl. My experiences have been different than yours, because I do require some method of dampening the vibrations. It's possible that the thinness of the walls has something to do with it.

Thanks for your comments.....

ooc

 

[john lucas]

Odie It's large enough to do 12" hollow vessels. It has enough adjustment to do spindles. It shimmy's a little. I made it out of wood with inline skate wheels. If I make another one it will be out of steel or at least thicker wood. I used plywood but I think I should use a thicker glue up. It works, just flex's a little when I use it.

 

[Joe Greiner]

Odie, the way you have it set up is intended to provide support at the cutting location, where it's needed. The link you cited on another thread has it on the other side, which makes no sense to me.

I made a four-wheel steady, so that the upper part could be separated for a piece that needed many re-settings. It's still not as rigid as some of the commercial or DIY rigs with three wheels, and it sometimes needs adjustment, but that "weakness" reduces the damage it might do to the work.

I don't think adding more wheels provides an advantage, and might even make matters worse. I always form a circular track for the wheels (turned between centers) before using the steady. I don't recall using it on any bowls.

 

[MichaelMouse]

I've the Oneway, and as long as it holds the portion under the tool steady, I'm happy. What happens on the other side has never been of particular interest, and I have not seen any negative effect. The rest pushes any incipient warp back into line so I can maintain a constant thickness all the way around, and that's why I can do the final fairing/paring cuts from rim to button. If you still have yours converted to exert only spring pressure, you won't get full benefit of the first, and may be forced to exert some pressure against the bevel to get the second. Which pressure can also distort the shape of the thinnest pieces as you work them, reducing the benefit from the first.

Before I had him I used to wrap or tape the outside of the piece to minimize flex. It wouldn't help with thicker rim at the endgrain, but it took the rattle out. Since I cut long, narrow, and with full support from a rest, I was able to keep the tool cutting while only leaning on the bevel.

Takes only one finger to stop a tuning fork tine, right?

 

[Odie]

Odie, the way you have it set up is intended to provide support at the cutting location, where it's needed. The link you cited on another thread has it on the other side, which makes no sense to me.

I made a four-wheel steady, so that the upper part could be separated for a piece that needed many re-settings. It's still not as rigid as some of the commercial or DIY rigs with three wheels, and it sometimes needs adjustment, but that "weakness" reduces the damage it might do to the work.

I don't think adding more wheels provides an advantage, and might even make matters worse. I always form a circular track for the wheels (turned between centers) before using the steady. I don't recall using it on any bowls.

Mornin Joe......

Yes, that's exactly what I'm thinking, too. The Oneway provides support at the precise location your tool is working, and I can tell you from experience that it works. Now, can it be improved by adding wheels?.......that's what I can't say, and the real purpose of this thread.

Funny you should mention the link I posted to point out a "disorganized" shop. In that link, that person used his Oneway on the back side. I have done that, and there is merit to it, but only because the Oneway obstructs clearance for tools working on the outside surface. In that case, putting it on the back side is better than nothing, but to position the Oneway on the correct side is better for sure.

I tend to agree that adding many wheels probably won't add to the dampening effect, but I'm not convinced that three isn't better than two, and I gave my thoughts on that previously. On the same thinking, I'm not so sure than four wheels are better than three, either. This is because I'm not convinced that two sets of diametrically opposed wheels is better than three wheels separated by 120 degrees. (This, I don't know, and am only guessing at.)

ooc

I've the Oneway, and as long as it holds the portion under the tool steady, I'm happy. What happens on the other side has never been of particular interest, and I have not seen any negative effect. The rest pushes any incipient warp back into line so I can maintain a constant thickness all the way around, and that's why I can do the final fairing/paring cuts from rim to button. If you still have yours converted to exert only spring pressure, you won't get full benefit of the first, and may be forced to exert some pressure against the bevel to get the second. Which pressure can also distort the shape of the thinnest pieces as you work them, reducing the benefit from the first.

Before I had him I used to wrap or tape the outside of the piece to minimize flex. It wouldn't help with thicker rim at the endgrain, but it took the rattle out. Since I cut long, narrow, and with full support from a rest, I was able to keep the tool cutting while only leaning on the bevel.

Takes only one finger to stop a tuning fork tine, right?

Howdy MM.....

The incipient warp does enter the perspective in total, but I'm mainly concerned with oscillation, or as in your tuning fork example......"resonating" might be a good word for it. This isn't something that is much of a problem with bowls that have a substantial wall thickness, but it becomes a player in the scheme of things when doing "thin wall".

With the oscillation, I've a suspicion that a three point set-up might be better than a two point set-up, because the "whip" will have lesser of a chance to occur when there isn't as much free travel before coming in contact with a wheel again. Still, this is only theory on my part, so I may be totally off base in my thinking! 😀

Funny you mentioned the spring I attached to the swing arms on my Oneway bowl steady. (The spring is visible in post #1 of this thread.) Yes, it is still there, and I still use the spring, but probably not more than 5% of the time. Most of the time, I have the swing arms locked in solid. When I do get a bowl that has significant warping, the spring does come in handy. The swing arms are free floating and wheels pressed into the bowl wall against spring pressure. This allows for some "give and take" in how the wheels respond to the revolving bowl. The lathe rpm must be way down for this to work, but it's very useful from time to time. :cool2:

ooc

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PS: If anyone is interested, here's a link to another discussion on this forum recently. It's probably the starting point of why I'm now considering getting a rigid three point bowl steady rest. Yes, they are expensive, but my lathe turning is an important part of what makes me.....me! 😀 I haven't pulled the trigger on this yet, but am seriously thinking about it......

click:

http://www.aawforum.org/vbforum/showthread.php?t=6712

ooc

 

[MichaelMouse]

Yep, the wheel just prior to the cut dampens any movement carried from above, while the wheel below the tool stabilizes it afterward. Thinner the turning, the more likely it is to flex, but I set the wheels so it doesn't happen where I'm working.