|Forum topic by summerfi||posted 04-24-2015 03:42 AM||1875 views||0 times favorited||22 replies|
04-24-2015 03:42 AM
First let me say I’m not trying to be a smart aleck with this topic. I’m simply trying to better understand the process that occurs when we say a wooden tool handle such as a plane tote or a saw handle has “dried out” and needs to be oiled or rehydrated.
On many occasions I’ve heard people say something like, “that handle is all dried out. Better put some boiled linseed oil (BLO) on it.” Not to pick on anyone, but there is currently a LJ thread by a fellow who wants to know how to rehydrate his plane tote. This makes no sense to me for several reasons. First, a living tree has a high moisture content, and it’s not suitable for most uses until we dry the lumber. Kiln drying brings lumber down to, I believe, around 6% moisture content. So why is dry wood good on the one hand and bad on the other? Second, wood will eventually take on the same moisture content as the ambient relative humidity. Not many places have a relative humidity drier than 6%, so in most cases the tool handles in your shop will have a moisture content higher than kiln dried lumber. Third, I have a considerable amount of hardwood lumber that was stored in the attic of my dad’s shop for upwards of 50 years. If any wood can be too dry, this wood should be. Yet it is perfectly good wood and shows no signs of needing to be oiled or hydrated. Fourth, I have many vintage tools in my shop that are 100+ years old. These tools show no indication that their handles are too dry and need some sort of treatment to restore them to wholeness. Fifth, with the exception of some tropical hardwoods, most wood does not naturally have much oil in it. Why would we need to add oil to it?
All that being said, I’ve certainly seen tool handles that have the appearance of being dry. I restore a lot of saws, and I often see old saw handles that have checks in the grain and the wood has a dead, lifeless, bleached out look. These handles are what someone might call “all dried out”, but is that really what has happened to them? I would bet that if you measured the moisture content of these handles, it would match the ambient relative humidity. If these handles aren’t too dry, then what has happened to them? Well, I’m hoping to stimulate some discussion on that so we can all become more knowledgeable. But here is my theory for starters. I think there are at least two things that can contribute to the dry look. One is repeated wetting and drying cycles (expansion and contraction of the grain), such as occurs when tools are left outside in the weather. The other is exposure to sunlight. Imagine two 100 year old tools in the same climate. One’s handle looks perfectly fine after all that time. The other’s handle is checked and lifeless. What has made the difference? It has to be exposure to the environmental elements.
So what do you think about this? Is it a misnomer to say tool handles are dried out? By the way, I never add BLO to wood because IMO it turns wood dark and is a magnet for dirt.
An old “dried out” saw handle (photo from the internet).
An even older saw handle in good condition.
-- Bob, Missoula, MT -- Rocky Mountain Saw Works http://www.rmsaws.com/p/about-us.html