About That Wall Thickness / Shrinkage Thing
You've got this freshly cut half of a short log that you want to turn into a bowl. You know it's going to shrink as it dries - very little ALONG THE GRAIN, more between the growth rings - and will shrink most ACROSSED THE GRAIN. And you also probably know that unless you do something to reduce or prevent it, your turned green bowl will warp all over hell - and/or - CRACK / SPLIT / SELF DESTRUCT - as it dries.
You've got two basic choices as to how to orient you bowl within the logette blank.
Your turned from a logette bowl WILL change dimensions as it dries - and keep changing dimensions once "dry" as the temperature and humidity of its home changes. What follows will, based on Bowl A, hopefully explain why - in which direction - and how much and discuss things you can do to minimize shrinkage affects.
1. An overview of what happens as a turned "green" bowl dries and some terms to learn
Same basic bowl - turned in two different woods
2. Radial and Tangential Shrinkage Percents and what the latter does to your bowl as it dries.
3. Lets look at Tangential Shrinkage in terms of specific numbers.
4. And now let's look at Radial Shrinkage
5. Let's look at Radial Shrinkage with some actual numbers.
LINKS
Woodbin's Wood Shrinkage Table (I hope to put this info in an Excel spreadsheet to make it easier to search and sort)
If you have questions, comments or suggestions for improving this stuff PLEASE e-mail me