Sawmill Process from Start to Finish & When to Make What Decisions

What Decisions to Make & When

While every tree has its own story to tell, the process build that story is fairly consistent. We will explain this process here, along with what you need to be thinking about at the various stages in the process.

Step 1 - Bucking The Logs

The first step in the process is turning a standing tree into logs. Regardless of whether the tree has fallen in a storm or whether it is being cut down by a tree company, the first decision that must be made is what length to cut the logs to (commonly known as bucking the log). Here are the factors to consider:

Begin with the end in mind. What are you going to use the wood for? If your plan is to build a dinning room table, what is the largest table you can fit in the space. If it is 8 feet, then you don’t need to cut the log at 18 feet. Keep it to 10. On the other end of the spectrum, if you want to turn the wood into shiplap for a 12 foot long room in your house, you could cut the logs at 14 feet. If you just aren’t sure what projects you will use the wood for yet, then you should consider two things. First, where will you store the wood? If its in the basement against a 10 foot long wall, then you might need to cut everything at 9 feet. Second, what size board can you handle? Can you enlist help to move the lumber? A 14 foot long 2×10 piece of white oak can be quite heavy. If you really aren’t sure, then I recommend cutting everything between 9 and 10 feet. That size is easy to handle at every step of the process, including the end.
Limitations of your tree company or the location of the logs. Logs are heavy when they are first cut. Up to 50% of their weight can be from just water trapped in the logs. Some companies have to cut the logs shorter because of the limitations in their equipment. Sometimes the logs are in awkward locations and they can’t move long logs without doing more damage.
Transportation of the logs. The means by which you are moving the logs can limit the length of the logs. Most grapple trucks are limited to 21 feet, and dump trailers can range in size.
We prefer logs no longer than 20 feet. The sawmill’s max capacity is 21 feet.

Step 2 - Transportation

There are a few options here. Sometimes your tree company can take care of the transportation for you. Let them know ahead of time you would like the wood transported to our location and they can build that into the price. They will need to coordinate with us to drop off the logs because we have a log yard located on the property with its own entrance and a different road than our main address. This is the only location than can drop off logs at.

If they can’t transport your logs for whatever reason, we work with a grapple truck company that can come and pick up the logs for you. They do charge for this service, but they are very professional and know just where to place the logs when they get here.

Step 3 - Evaluating the Logs and Cost

At this stage, we measure the length and diameter’s of the logs. Using this information, we can estimate the board feet in each log using the ‘Doyle Log Rule.’ This Rule is a mathematical formula that makes several assumptions about logs in general to estimate the total board feet. With the estimated board feet, we will send you a proposal of the approximate cost. The more information we have, the more accurate our estimate will be. For example, if. you already know how you want us to mill the logs, then we can be more precise on the kiln costs. If you aren’t sure at this stage, that is not a problem at all. We will just make certain assumptions to give you an rough estimate.

We will require a deposit of 50% of the estimate to get things started. The remainder will be due at delivery of the milled and dried wood. Final adjustments to the bill will be made based upon the actual board foot milled as well as the total time the wood is in the kiln based upon its thickness. The board feet are calculated while the wood is still green and a breakdown of everything that was milled will be emailed to you. The wood will, of course, shrink during the drying process.

Step 4 - Milling and Air-Drying

When we have reached this stage, you will have to have made a decision on how the wood is to be milled, because we can only saw the log one time. You can, of course, re-saw the wood on your bandsaw later. That is why we tend to recommend 6/4 and 8/4 lumber if you are unsure what you want to do. This gives you lots of choices. With 8/4 boards, you can re-saw them into two 3/4 boards without too much trouble after jointing and planing the boards one one side.

As the logs are milled, we stack and sticker the lumber and move it to one of our air-drying stations. From there, we wait for the wood to loose its ‘free water.’ There are two kinds of water in wood, free water and bound water. When trees are growing there is water being pulled through the wood from the ground up to the tree’s leaves to assist with transpiration. This water is called free water because it exists in water form and can be removed relatively easily from the wood. Bound water is water that becomes part of the wood fiber itself, and is more difficult to remove. Some species of wood are more than half water in terms of their weight when they’re fresh cut. Oak, on average, weighs 5.4 pounds per board foot when it is wet, and will weigh 3.5 pounds per board foot once it has reached 8% moister content.

Step 5 - Kiln Drying & Sterilization

When wood is dried, the first thing that happens is that the free water evaporates until the lumber drops to what’s called Fiber Saturation. Fiber Saturation is generally reached when the moisture content gets around 28%. At that point, all the free water is gone and only bound water remains. The most economical way to dry any wood is to allow the moister content to get down below 28%. For thicker slabs, we let it air dry down to 22%. Allowing it to air dry over the course of 3-12 months should achieve this moister content (it can be longer for thicker pieces). The 9 month range depends on the weather and the thickness of the wood. We will check the moister content from time to time to see how it is progressing.

By allowing the free water to evaporate naturally, you can nearly cut your drying time in the kiln in half. Our dehumidification kilns can dry 1 inch thick oak from green (right from the sawmill) to 8% in about 35 days (this is an average). You have to add around 35 days for every inch of thickness. So, a three inch thick slab would dry from green to 8% in roughly 105 days. By allowing it to air-dry first, you reduce the kiln time down to 52 days for three inch thick lumber. Sometimes, thick live edge slabs can take longer. Once the wood has reached 28% moister content, we will move it into the kiln as soon as a spot opens up. The kiln will not only finish the drying process, it will also sterilize the wood.

Sterilization is a very important step. Kiln drying itself may eliminate some of the insects, but it won’t eliminate their eggs, which can lay dormant in the wood for long periods of time. To sterilize the wood, we increase the temperature in the kiln to at least 150 degrees after the wood has reached 8-10% moisture content. This temperature pushes the core of the wood up to a temperature of at least 133 degrees, the temperature needed to kill the insect eggs. For one inch thick lumber, we typically keep the temperature at 150 for a day for each inch of thickness.

Step 6 - Pick Up

Once the wood has finished the sterilization cycle, it is ready to be picked up! We typically bundle the wood together for you so that it can be easily loaded onto a trailer for you to take home. We do can deliver the wood back to you for an additional charge, but we do not currently have a consistent delivery schedule. In other words, you might get your lumber faster by picking it up.