Considering First Segmented Turning

Take a look at Kevin Neelley's web site. He provides a lot of good information on how he does his segmented turnings along with software to aid in design/layout for the segments.

Some of my sources

... and my first effort

JD wrote:

I do segmented work and sell my work in a few galleries here in Hawaii. Buying wood gives you the opportunity to get relatively consistent stock, but you can do segmented turning with "found" stock.

If you don't have a planer of some sort, plan on a lot of sanding to prep the wood before and/or after you cut segments from it. It may not be necessary to plane the wood first, but it makes things easier down the road.

I'm sure there are quite a few web sites out there with instructions on how to make segmented vessels, but a few things that may help:

If possible, start with wood of the same moisture content. This does not mean it needs to be kiln dried, but it does need to be dry.

If possible, start with wood that is planed to the same thickness. This will minimize sanding individual rings before gluing them up into the vessel shape.

Begin with a plan. I use simple graph paper to draw the profile of the vessel, then transfer the "measurements" of ring diameters to an excel spreadsheet to compute the actual cut lengths for segments for each ring. You can use one of the programs available online, but if you don't have the concept first, the program won't really do what you want. Some are quite cumbersome to draw the profile, and I can draw a new profile on graph paper and input it to excel in far less time than learning how to make the program work to draw the same sort of curves... (and I've used more than a few graphics programs, including Autocad.)

Plan on a long time to complete a segmented project, at least the first time or two. To be even minimally efficient requires some jigs or precision setups for the angles involved, and getting the jigs or equipment set up takes some time. Once you have the setups, the amount of time per vessel isn't bad, but it's spread over a relatively large amount of calendar time. A 36" tall 11" diameter vase may take less than 40 working hours to execute, but takes nearly 6 weeks due limitations on how many rings I can do at once without waiting for them to dry. Major steps are cut segments, glue into rings, surface rings flat, glue 4-5 rings to project, turn the shape, and repeat until the project is done. Given I have a full time job paying the bills, I have a limited number of hours available each night and weekend. However, in full cycle I can turn the 4 rough rings on the project to size, surface the 4 rings I cut and glued last night and glue them to the project, and then cut segments and glue up 4 new rings and get them into the kiln to dry overnight. Thus, I can move up 4 rings per day until I get to final sanding and finishing. The first segmented vessel I made seemed to take forever, but now, I plan about an hour per ring average for most of my projects, but I have an established process and don't need to set up jigs or equipment any more. Just the difference in making the hold down for the first chop saw was an amazing time saver.

For the vessels I do, I use either 18 or 36 segments per ring. This is a lot, but gives me more flexibility for patterns in the vessel. I have one miter saw set up with a 5 degree angle, (which produces segments for

36 segment rings) and another with a 10 degree angle (which produces segments for an 18 segment ring). Both feature shop-build "micrometer" fences to ensure exact segment length esired is what is cut, and spring loaded hold downs to keep the cut segment in place so I don't have to cut, release the trigger, and wait for the blade to stop before I raise the blade. (Raising the blade while it is spinning will often catch the segment and toss it backwards, denting or damaging it and potentially me if it were to bounce.) Once I got the two chop saws set up with precise angles, I haven't used them for anything else. Given a precise angle and a sharp blade, there should be no reason to sand individual segments before gluing into rings. Simple miter saws are preferred, as the more expensie, sliding miters are not quite as stable in the long run.

Really big hose clamps (188 size at Napa parts store, or other large ones from a commercial pipe supply house) are good for gluing up rings. These will do about 10" diameter, and can be extended with other clamps of the same width. Smaller projects use shorter/smaller clamps.

Try to use woods with the same relative hardness. When you sand, (and to some extent when you turn) the soft segments will sand away more than the hard ones, resulting in a wavy surface instead of a round one.

When you glue up rings, try to keep the grain consistent. Each segment should be cut with grain paralell to length of the segment. When the segments are glued into a ring, you end up with the grain running around the ring. (the glue joints of each ring are end grain joints. They aren't terribly strong, but when the rings are glued together, the parallel grain between rings is extremely strong. Avoid cross grain glue joints if possible, because periodic given moisture changes, the glue joint will eventually fail. Titebond II or a similar glue works just fine. If the segments are cut accurately, you shouldn't have any gaps within a ring, and if you surface the rings flat, you shouldn't have any gaps between rings. I use a 24" disk mounted on my lathe to flatten each ring (typically within a few thousandths of an inch) before gluing the rings to each other. If you want grain to run vertically, you will be doing "stave" work, and will want all grain in the project vertical. Cutting a staved project is much more difficult, especially at first, as you need compound angles on each segment. For this you almost must use a table saw sled (which could also be used to cut segments for regular flat rings).

As you glue the rings to the project, you can get away with bar clamps, but it's a juggling act at best to get them on and the rings concentric to the project base. A press works much better (though takes time to build). An alternate is a bunch of weight. Before I built my press, I'd gotten away with putting a plywood disk over the project and carefully setting a 5 gallon bucket of sand on top when I didn't have clamps that were long enough.

If you are making a vessel with relatively vertical walls, don't glue up more than 4 or 5 rings before you turn them. Two reasons: 1) you probably don't have tools that can reach safely much more deep into a vessel unless you do deep turning already, and 2) any inaccuracy in cutting or gluing will cause the rings to be out of round and/or each ring to be offset, which is compounded the more rings you add at each step. Also, if you don't get the rings surfaced flat, you will also cause it to be off axis compared to what you expect.

Color combinations are a personal thing. Most of my projects use Koa as the base, Alder or Maple, Purpleheart, Padauk, Walnut, Mango, Brazilian Mahogany, Wenge and others as accent colors depending on the design. Use what's available to you for the first one and get more creative as you go along.

Good Luck!

--Rick

I'm no expert, but I've made a few, and they all turned out pretty good.

I like free too- one of my favorite segement projects was made from a box of mesquite cutoffs that a guy sent me for the cost of shipping after he installed a mesquite floor. They were little triangles, but wood doesn't need to be big for segemented turnings.

Try the flooring guys. Otherwise, yes, scrap bins from anywhere that uses hardwood are a gold mine for what you're contemplating. I do more flatwork than turning, so there's always plenty of scrap around for me.

I don't suppose it would have to be, but I don't think I'd personally bother with trying to make a segemented turning out of wet wood. There's a chance it would tear itself apart as it dries, and that's a lot of time to invest for that to happen.

They matter, but if you have a light touch, you should be able to mix whatever you like. The only warning I have for you is that soft white woods like aspen or basswood will pick up color from darker woods when you sand it, and look sort of dirty. Better to use a hard light wood, if you need it to stay bright.

Carpenter's glue is fine. But don't jump the gun- you can usually keep working after it tacks with flat work, but when you spin it on the lathe, you really want to let it set up for 24-48 hours first.

sources

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