Some split

[Yathin Krishnappa]

I was moving around some blanks today and noticed one that seemed to have an amazing twist. It was much more than a twist.

401770

It has probably been that way for years now!? The top picture is another blank from the same group.

[John K Jordan]

I was moving around some blanks today and noticed one that seemed to have an amazing twist. It was much more than a twist.
401770
It has probably been that way for years now!? The top picture is another blank from the same group.

What wood is it? I've had dogwood split like that and holly warp like that. This is holly.

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I noticed when cutting boards on my sawmill the board was more likely to twist if the grain isn't parallel to the axis. But your's doesn't look like that! Hard to tell, is it a combination of twist and bow?

Maybe that was reaction wood with a lot of stress built in. Or could there have been an invisible crack in the end when the blank was cut? Before sealing I like to check green wood for existing cracks across the ends by cutting off and bending a thin slice, removing enough until the crack is gone. This seems to prevent splitting while drying.

JKJ

[Yathin Krishnappa]

What wood is it? I've had dogwood split like that and holly warp like that. This is holly.

John, this is satinwood.

I think you are right about the reaction wood, I did take a closer look now and that seems to be the case.

Out of curiosity, do you know if this would have likely split while turning when it was a bit greener and didn't show any signs of defect?

[John K Jordan]

...Out of curiosity, do you know if this would have likely split while turning when it was a bit greener and didn't show any signs of defect?


If turned green and there was no existing crack it would probably have stayed together, then possibly warped after turning (unless turned into short things). Whether it split or not might depend on how much wood was removed and where, allowing stresses to be relieved.

The stresses after drying can be considerable. Some months ago I was turning a small platter from very dry 2x8 hard maple stock - prepared the blank, mounted on the lathe, then walked across the room to sharpen a couple of tools. I heard a "snick" then a loud "crack" - the blank developed a deep crack about an inch into the end grain. The possible stresses in any wood are the reason I follow the same procedure many use when turning lidded boxes - even if the wood is completely dry and even if rough turned, before finish turning I always leave it on the lathe for a few hours or overnight to allow any internal stresses to relieve. Not much danger in cracking there, but a box base or lid blank that goes out of round after finish turning is pretty much worthless.

Boiling wood
One thing that will stabilize even severe stresses is boil the wood. Boiling used to be very common with woodturners but we don't hear much about it these days. Too bad. The heat from the boiling apparently softens the lignum and allows the internal stresses to be relieved, reducing cracks and warping (which causes cracks)

Some wood blanks are always boiled - I have blanks of madrone burl blanks plain madrone that have all been boiled. Some exotics are boiled - a wood dealer I knew from Peru said they always boiled roughed out bowls eventually sold in the US and elsewhere - boiled in 55-gal drums over wood fires. I got some big green blanks from him and he warned me they would be splinters unless I boiled them.

You can search the net for info about boiling. Some years ago turner Steven Russell was one of my go-to sources for wood and turning information. He had a wonderful article about his research on boiling but his web site no longer exists. A number of people have included Steven's work in their own writings, some on turning club web sites. For example, some PDF files I found with a quick search:

Boiling wood: azwoodturners.org (azwoodturners.org/pages/tips/boiling.pdf)
Boiling wood: eddiecastelin.com (eddiecastelin.com/yahoo_site_admin/assets/docs/Boiling_wood.104103931.pdf)

A search of Sawmill Creek will show some discussion threads.

And fortunately for all of us, the Steven Russell web site is available through the Wayback Machine, the internet archive. Access is VERY slow but it's all there.
https://web.archive.org/web/20170930122830/http://www.woodturningvideosplus.com:80/boiling-green-wood.html

His other articles are also available there - some incredibly valuable stuff!! I am gradually coping the pages to my own system for quick access. If you get time browse some of his articles in the Main Library and the Tips Library. Or at least bookmark the page for later.
https://web.archive.org/web/20171003014045/http://www.woodturningvideosplus.com:80/woodturning-education-articles.html

Much of Steven's stuff is geared towards bowl turning but nearly everything applies to general woodturning.

A list of just a few of Steven's articles, compiled by Gary Guenther:
Air drying with end grain sealer
Paper bag drying
Boiling 1 and 2
Cryogenic tool treatment
Wood stabilization
Dealing with torn grain
Oil finishes -- Reducing color change in light woods
All about wax finishes
Microcrystalline waxes
Buffing
Coloring, burning, metal leaf
Using wood dyes
Super glue tips and tricks

JKJ

[Prashun Patel]

Even that top blank has some run out that may work against it. That's not to say it will split during drying. However, the right side may be weak and not an optimal choice for a tool handle or chair leg.

[Yathin Krishnappa]

Thanks for this wonderful information John.

[Yathin Krishnappa]

Thanks Prashun. I hadn't noticed it! I'll have to take a closer look at the blanks from this batch now. :-)