Optimal bowl grain orientation?

[Sean Hughto]

I've turned maybe 20 bowls at this point, mostly from wood that was either green or not fully dry. Sometimes I've gone the rough out mode, and other times gone straight to final, but in either case threats of warping and cracking exist. My question is whether there is a conventional wisdom developed by expereinced sorts as to whether a bowl has a better chance of resisting cracks or warps in less undesirable ways if one orients the grain so that the bottom of the bowl is deeper into the heartwood and rim is toward the outside fo the tree or vice versa?? Thanks in advance for any thoughts and experiences.

Often there is a tendency to want to make the base at the outside because that allows the largest bowl when the radius of the tree chops off the edges of the blank. My limit expereince so far is that orienting the bowl the other way - bottom in the heartwood - is superior when possible, but I could be wrong.

[Dennis Ford]

I make bowls oriented all sorts of ways. When you have small logs to work with, the options are limited. With bigger logs, more choices. I think having heartwood at the base and sapwood at the rim looks better than the other way around for woods that have a lot of color contrast. You are likely correct about the tendency for cracking but that can be controlled with even thickness and careful drying so it is less important to me. I am not saying all cracks can be prevented, it happens. I prefer to design for appearance and attempt to prevent cracking, then if it cracks too bad toss it. Turning to final thickness while wet will eliminate most cracking problems if the design is compatible with warpage.

[Kyle Iwamoto]

Getting the pith out is one (not the only one) of the major sources of cracks. I try to cut the blank through the pith, or, on the smaller blanks, so that the tenon is on the pith and gets cut away.
I personally like the bottom of the bowl inside also. But it's not always the case, sometimes I like the bottom on the outside. That gives that cool circular heartwood at the rim. It all depends on how I feel at the moment of that first cut. Sometimes I do end grain too. In other words, I don't think there is a "best" way to orient a bowl.

[steven carter]

Sean,

One thing I have learned has more to do with how the log is split into the two halves. If the pith is in the center of the log then it really doesn't matter much, but often the pith is off center. When this is the case you usually have a log with two different growth ring patterns. The growth rings on the side nearest the pith are usually closer together, and the rings on the other side farther apart. I get less cracking if I cut the log in half so that the close rings are in one half and the loose rings in the other half. If you end up with a log with half close rings and half loose rings, my experience is that checking is more likely. I think if you pay attention to how you half the log, you will have better luck.

Steve

[Wally Dickerman]

With the bottom of the bowl oriented in the heartwood, near the pith, you will get a smaller bowl but the grain pattern will nearly always be more attractive.

Wally