Grain orientation in segmented turnings....

[Doug Rasmussen]

Is a certain grain orientation better than others? When viewing the turned object the exposed grain might be end, edge or flat. Does it make a great deal of difference which is used? I can see you might not want to mix grain orientations, or does that work?.

In this video I would term those segments as edge grain. https://www.youtube.com/watch?v=6Yl-qDN1HtI


(https://www.youtube.com/watch?v=6Yl-qDN1HtI)

[John K Jordan]

Is a certain grain orientation better than others? When viewing the turned object the exposed grain might be end, edge or flat. Does it make a great deal of difference which is used? I can see you might not want to mix grain orientations, or does that work?.
In this video I would term those segments as edge grain. https://www.youtube.com/watch?v=6Yl-qDN1HtI
(https://www.youtube.com/watch?v=6Yl-qDN1HtI)

Maybe called side grain? The terms edge or side grain might depend on how the wood is cut from the log, flat sawn, quarter sawn, or something in between. But the orientation of gouge to grain would be essentially identical.

I would just avoid end grain if possible due to the increased chance of tearout. If you like videos, this guy mentions it: https://www.youtube.com/watch?v=ZFWvToGL_9kI

[Pete Marken]

It is best to not mix grain alignment. For segmented construction it seems that side grain works best horizontally. It can be used vertically as spacers between segments but they need to be thin 1/16 or less to avoid erratic wood movement. I have used end grain at times with black palm. This gives a striking appearance. I do agree with John and try to avoid end grain. One of the advantages of segmented turning is not having to deal with end grain.

[Blair Swing]

Purists sometime frown on end grain, although it can make design bands a lot easier to build if you use as usage technique.

Myself I have used both, side grain on field and edge grain on the design band, with some veneer and really thin Baltic birch plywood between the field and design bands to allow a bit of differential movement. Going on 2 years on one piece and nothing you can feel on the outside yet.

As as my skills improved I have always tried to use edge/side whenever possible.

The other big difference though is color, and the edge grain will suck up more finish, or just appear different color than side, even from same board. That can be fine as long as you know it and expect it to happen. Never mix eye and side on the same ring.

[Doug Hepler]

Doug,

In my lexicon, the distinction is between segments (and compound segments) where long grain runs horizontally (right angle to the axis) and staves, where long grain runs vertically (parallel to the axis). Segments are then glued end grain to end grain, but of course when they are laid up into a blank the rings are glued long grain to long grain. Staves are glued long grain to long grain around the vessel.

As previous responses have said, end grain does not show to the inside or outside of the turning in either type of construction except as part of a glued-up feature. For example, just to pick the simplest, you could drill a hole through a segment and then insert a dowel that would produce a circle or elliptical show surface in the segment. It would show end grain and would show darker because it was end grain.

The choice as to radial or tangential grain showing depends on the wood and the pieces you have to work with. Obviously if you have curly maple or whatever you would want that to show. With some woods with prominent grain (zircote, etc or even oak) you can get some great effects as the grain extends around the vessel.

Doug

[Robert Marshall]

I've done some segmented bowls, and I've always used "scraps," leftover pieces of wood, and sometimes plywood, even glue-lam (engineered wood beams). Great way to convert scraps from firewood to finished work.

Leftover boards I usually cut into strips (which are then cut into the segments for the rings), always ripping along the grain to make the strips. One of the nice things about segmented turning is that you are pretty much always cutting with the grain, especially if your rings are 12 or more pieces. Smooth!

Plywood and similar composites can be cut into strips in any direction, since the grain in these composites alternates direction with each layer, perpendicularly.

[Don Jarvie]

If you have thick enough boards you can use the face grain, aka using the tops of the boards if you were making a piece of furniture. Sometimes that grain can can be very interesting.

[John K Jordan]

If you have thick enough boards you can use the face grain, aka using the tops of the boards if you were making a piece of furniture. Sometimes that grain can can be very interesting.

I don't know exactly what you mean by "face grain" or "tops" of the board. To be clear, the orientation of the exposed rings, rays, and figure on the top or wide side of a board depends on how the board is cut from the log. For a given board, the orientation of the figure due to the rings can vary widely. If you look at the end grain of some random boards this is obvious.

I found this picture which nicely shows how boards are cut from a log.

http://s3files.core77.com/blog/images/2013/06/wood-plainsawn-02.jpg

If the board is truly quartersawn as in the middle diagram, if you look at a wide side of a board you are looking at a face cut radially, exposing the ends of the annual rings.

If the board is "plain sawn" or sawn "through-and-through" as in the left diagram below, some of the boards will expose the tangential figure on their widest faces, looking at the rings nearly parallel to the surface. Some will have radial grain exposed, and most will be something in between where the rings intersect the wide face of the board at some angle. Notice how the rings intersect the widest faces of the boards at the top and bottom of the log as compared to the single board in the center.

The right-hand diagram shows a way some sawyers use to maximize the number quartersawn or near-quartersawn boards. But you can see the angles of the rings to the faces of the boards change as you cut further from the center of each quadrant. True quartersawing is not often done since it is wasteful and time consuming.

Quartersawn boards slice the long way through the rays. For boards with prominent rays (oaks, etc) you will see the rays, long and wide and quite distinctive. The rays of some wood (sycamore, cherry, etc) will give an interesting ray fleck pattern when quartersawn. Others are nearly invisible. Boards with the rings exposed at an angle are somewhere in between and don't exhibit the distinctive features of either of the others. The rings will be the closest together on a quartersawn board.

Quartersawn boards are much more stable since the shrinkage rate is more consistent across the board. Those cut like the second, third, etc boards down on the left diagram are prone to cup when drying since the tangential shrinkage rate in most species is higher than the radial shrinkage rate. (The T/R ratio) To make it interesting, boards cut at an angle through the log relative to the pith can also twist as they dry.

When I saw logs I generally either plainsaw or trim boards off four sides until I get the largest square "cant" I can make from the log then saw that cant through-and-through. That's the easiest thing to do and gives me boards fine for my use, mostly around the farm. I do like to cut some thick slabs and set aside the more interesting and clear boards for woodworking and woodturning. Plainsawing is so much quicker and easier than doing it another way, especially for my manual mill.

Just for fun, this is a cedar log I sliced up on my sawmill into 2" thick slabs, plainsawn. These slabs mostly went into shallow bowls and large turned platters and I made a number of the squarish platter/plates shown in the second picture. One piece from this log is shown at the top and the upper left of the three pieces.

343402 343404

The point of all this is you can't assume the grain/figure/ring orientation of a given board without looking carefully at the board or examining the end grain. If the board is indeed thick enough you do have the option to slice segments from the edge or the face or even at some angle to maximize the interesting figure.

For anyone interested in this and much more about wood, my favorite source is the book "Understanding Wood" by R. Bruce Hoadley. I've flat worn my copy out so the cover is falling off.

BTW, when digging through boards at the lumber yard you can almost always find a few great quartersawn boards in every bundle.

JKJ

[Don Jarvie]

John thanks for providing more detail. I had some soft maple that had interesting face grain so I used that for the bowl.