Tornado Bowl - Open segment beginner project for Stomper/SegEasy

[Lloyd Johnson]

Here's a 3D Design PRO and Woodturner PRO design that is a fun project for those just getting started in open segment turnings - especially if you're using the Stomper.



I designed it for the 18-segment plate and have sized the rings so that all segments in the open segment rows can be cut from just two widths of boards - 1" and 5/8". With the tornado pattern, one of every three segments is walnut and the other two are maple. So cut all material for both species at the same saw setting and when you cut your segments, stack two maple and one walnut and cut three segments at a time. I'm just finishing a video that will shows a jig that will simplify this process and make it very safe so keep an eye out for it.

I wouldn't do any turning at all until you've added the final closed segment ring. This will lock all the earlier open segment rows in place. Then turn the inside first, starting at the top ring and working towards the bottom so that you're leaving the bulk of the glue surface area where it can support the upper rings. Turn away the 5/8" centering hole and sand the inside of the bowl. Finally, turn the outside. If you have a live center cone or plate to provide light pressure from the tailstock, the bowl will turn like it is a closed segment bowl.

I've been saving a big chunk of walnut from the Columbus Day storm of 1964 and plan to make a lot of tornado bowls with various patterns for the 50th anniversary of the storm of the century here in the Pacific Northwest. Perhaps you can locate some blowdown of a similar storm from your area. It will increase the interest of the turnings.

You will need to have 3D Design PRO and Woodturner PRO installed to open the attachments.

Enjoy, and Happy New Year!
Lloyd

 

[Bob]

Lloyd, thank you for posting the Tornado Bowl project. I'm ready to do my first open segment project. I've installed the stomper and have the SegEasy plates. Everything seems simple enough until I go to setup for cutting the segments for Row 2. What?? A Miter Angle of 8.12 degrees? I admit to not knowing how to setup either my Kapex nor my tablesaw for 8.12 degrees.

I usually take my board, cut to the proper thickness and width, measure my segment edge length, set the corect miter angle and cut. Any advise on how to set my miter angle would be appreciated.

Thanks.

Bob Loyd

 

[Lloyd Johnson]

Hi Bob,

The thing to remember is that if you're using the 18segment plate, you will always cut all segments at8 degrees. Likewise, if you re using the 24- segment plate the angle is always 5,5 degrees. In the software, set the Auto calc field for open segment gaps to 20% for the 18- seg and 27% for the 24-seg plate and this will give you the correct cutting angles (rounding errors may occur).


I will have some new videos posted soon that will show how I cut segments on both miter and table saws. I think you will find these to be interesting.


BTW, both pâtés have the correct cutting angles engraved onto them so you can always refer to those numbers.


Have fun with your project and I hope you'll post pictures.


Lloyd


Sent from my iPhone. Message is likely to contain ridiculous spellings.

 

[Bob]

Thank you Lloyd. I like that answer. I will post pictures.

Bob

 

[John Payton]

Lloyd,
I have been busy roughing out solid bowls so they could be drying, but now hopefully have a little time to try out my new toys....so I was looking at your 'tornado bowl' for a good beginners project, and ran into the same question as Bob posted about cutting those different angles..but since I always thought (as was in your reply) was that the miter angle would never change (as long as you were using the same number of segments), my mind began wondering as to why the miter angles are changing in the WTP print out...??..and also, looks like the 'vertical spacer' is changing...what is that..??

Oh..and any update on the video your reference as to cutting segments.??

 

[Lloyd Johnson]

Hi John,

When you switch a ring to Open Segment, the Vertical Space either shows you the width of the gap if you have checked the box to let the software automatically calculate the open space based on a percentage, or it is a field that lets you specify the gap if you choose to set the gap manually. The new version of the software makes this a little clearer and also corrects some bugs about when the field is editable or not. That release will be available later this month.

The reason the angle can change from row to row is mostly due to rounding errors. I've also changed the code so that it recalculates after every change that is made and there is a possibility you are seeing one of the instances where that was not the case. As long as you have 20% or 27% for the 18 and 24 segment 'auto calculate' percentages, always cut your angles at 8 degrees or 5.5 degrees, respectively, and you'll be golden.

I mostly finished the videos and then decided that I really needed to target them more towards the beginner and so I am redoing them. Hopefully, it won't be much longer. Since I work as a business consultant full-time, my available time is limited. This working for a living is getting in the way of real important things such as segmenting. :-> I do plan on cutting back as soon as my current project is done in August. Then I plan on doing realtime online video projects where we build projects together and online attendees can ask questions as we go.

Lloyd

 

[Bob]

I've been working on the "tornado bowl" - using the Stomper and the 18-segment plate (my first open segment project). I have two more rings to add to the project but it's time for me to head to the airport to begin a 3-week journey. I'll complete the project after I return. My experience in using white glue:

I tried a couple of white glues (Elmer's & Gorilla's) without success. The Elmer's might have been too old, so I purchased a new container of Gorilla's from a store that has only been open a few months. Each time, many of the segments fell off as I tried to carefully remove the plate.

I then tried Titebond Original and experienced no problems.

So that leaves me wondering why I had the problem with the white glue if others are using it successfully.

 

[Lloyd Johnson]

Hi Bob,

Here is a post from Sawmill Creek that has opinions from a lot of people and they all recommend Titebond, as do I:
http://www.sawmillcreek.org/showthread.php?107968-Titebond-vs-Elmers

I do think the problem with Elmers was most likely the age factor, though. One thing it isn't, though, is white vs. yellow because Titebond is also white with coloring added for marketing purposes, according to a Franklin representative I know.

I use Titebond Original, although I have used II and III with equal success. For multi-generation laminations where I need to make sure that all joints are perfect and properly aligned, I use Titebond Extend which gives more setup time and that has saved my behind more times than I'd like to admit.

Have a great trip and I'll be anxious to see your finished bowl when you return.

Lloyd

 

[John Payton]

Thanks for your reply, Lloyd..seems like everytime I read one of your answers like this, I find it hard to stay at work at this pesky day job, instead of just getting up and going home to make some sawdust...oh well, if all goes right then in 378 days I will join the ranks of those who 'get to play all day'

Anyway, your answer made me realize that there will be times with certain designs that you will want to make the gap wider/smaller...I hadn't even considered that.

Thanks again...will be looking forward to more of your great videos..!!

 

[Chuck]

Good morning Lloyd! Please show this "newbie" the error of my ways. I have just finished glueing up my first open segment project, the tornado bowl, and my mind has become a little more twisted than normal. When you get a moment, will you review the calculations on the cutting summary you posted? There seems to be a disconnect (open segment?) between the cutting summary, the plan and my project. I used the Segment Stomper and the Seg Easy plate to assemble the bowl and I used your longworth chuck to attach the solid row on top. Here are my questions and concerns.

How can row 5 and 6 in the cutting summary have different OD and ID if the board thickness, segment lenghts and board widths are identical? I think I am doing something right as my two rings are identical.

My row 8 with the board thickness, segment edge length and board width listed in the cutting summary has an OD of 7 1/2" and an ID of 5 1/2" compared to your OD 7 1/16" and ID of 5 1/16". This leaves me with only 3/16" glueing surface between row 7 & 8 and leaves a 13/16" overhang. It appears that this ring is going to test my "delicate cutting technique" to the max! This may end up looking more like the aftermath of a tornado than I originally planned, but it has been a good learning experience.

In your intro you indicate that the project can be cut from just two widths of boards - 1" and 5/8", yet the cutting summary shows row 9 to have a 1 3/16" board width. Does this have any bearing on the different dimensions.

Thanks and I look forward to your reply, as I try to learn something new every day.
Chuck

 

[steveintx]

I was just getting ready to finally start this project and had the very same questions that Chuck has or had since he posted in 2013. I look forward to your replies before I start to cut the segments for this piece.

Thanks for your help,
Steve

 

[Lloyd Johnson]

Hi Steve,
With the greatest of confidence, I can assure you that all calculations from Woodturner PRO are correct. The important thing to remember is that the segment edge length (SEL) is the ONLY determining factor about the outside diameter of either an open-segment or a closed segment ring. The width of the board simply determines what the inside diameter will be. The wider the board, the smaller the inside diameter. In open-segment turnings, a 1/16" difference in the SEL will make a noticeable difference in the outside diameters.

One thing to take a look at is your defaults. If you go File > Options, you'll see that you can select between rounding at 1/32", 1/16" and 1/8". For open segment work, I always use either 1/16" or decimal inches. On a first project, you might consider making the rings slightly larger to give you a little more margin of error. It is easy to do this by selecting all the segmented rows by going Ctrl-A to select all the rows and then Shift-click row 1 to remove that row from the row selections. In the right column, click the 'Uniform' button. The data in the calculations windows are for the 'Anchor' row and that row is identified by the row number at the top of the screen. Take a look at the outside diameter and if it is 6-5/8" (for example) and you want to add 1/8" to all rows, type in 6-3/4" in that field and the outside diameters of all selected rows will be increased by 1/8". If you want to decrease the inside diameters as well, deduct the amount you desire from the number shown. Now just follow the instructions on the Summary and cut all the SELs to be exactly as shown.

I always cut extra segments because if any board is not perfectly placed when the cut is made, it will be immediately evident when you put the segments in place. Simply replace it .

Here's a tip about centering the base over the segmented ring that is on the SegEasy Plate. The plunger is not a precision instrument as it is hollow and can be forced out of alignment. Nevertheless, it will work just great for this purpose just by being diligent about the plunge. Once I've plunged a base with one or more rings onto the new ring, I'll check the alignment of the gaps from one side to make sure it is correct. Next, I'll rotate the SegEasy Plate by 180 degrees and check the gaps at that place. If it is not perfect, put pressure on the base at the first location so that it doesn't move and then move the base to align the gaps at the second location. Now turn the entire assembly to look at it from all sides to make sure that the gaps are aligned. This process just takes a few seconds, but having the gaps aligned will be both visually pleasing but will also let you know that your rings are perfectly centered and your turning will be far simpler.

Here's a tip about turning the vessel. DO NOT be in a hurry to do any turning. When you do put the turing on your lathe, it is OK to turn rings as long as you do not touch the last ring you have added. The strength of segmented rings is not guaranteed until another ring (or two) have been added above it so that they are locked in place.

Please let me know if you have any questions on any of this.

Good luck, and have fun. Remember that this is your first bowl and you will have surprises. You will learn from each one of them, though and each new bowl you make will go much faster and have continued better results.

Lloyd

 

[steveintx]

Thank you Lloyd for the response. I went ahead and moved to the latest software and with the file in the new program it showed different segment lengths for the rows. I have turned a few segmented projects so far and I have found that for me heavy duty scrapers have much less chatter and work well for turning the bowl. I did pick up a termite tool but I have not used it enough to form an opinion about it yet. It is so much easier to stack the bowls since I started using the stomper that is for sure.

 

[Lloyd Johnson]

Steve,

Those are very nice turnings and you are certainly on your way.

Everyone will have their own opinions as to what tools to use, and I'll share mine. An open-segment bowl is actually much more sturdy than it appears and the only time I've had a segment come off is when I didn't wait before adding a ring above it. Nevertheless, I do think it needs to be handled more delicately than a closed segment bowl. Therefore, I only use tools that make a shear cut as I think it is less stressful to the bowl to slice the fibers rather than tear them as scrapers often do.

There is an exception to this, though - and that is if a scraper is sharpened correctly, it has a burr and that burr makes shear cuts. The problem is that a burr on a scraper is likely to cut very aggressively and it is not always easy to control the angle of cut like it is with a gouge. A termite or similar tool that has a carbide cutter can either perform a shear cut or a scraping cut, depending on the grind of the cutter. I like the circular ones as they always have a cutting edge that can be quickly rotated to give a fresh cutting surface.

I rotate between gouges and carbide cutters, often grabbing whichever is closest.

Just my $.02. :->

Lloyd

 

[steveintx]

I agree that you have the grind on your scraper correct to get a shear cut. I sharpen them often as I turn and have found I can take some very nice cuts with them. I have the one way tools as well so I too switch between every seems to be making the better cut. The scrapers that I found that I like have at least 3/8" bar stock. The thinner ones I had would catch so I tried these and am happy so far. I will probably get a chance to get an open segment bowl into glue up this weekend. I'll be sure to post a picture of the finished product.

Steve