Making Lumber From Logs – How To
Making Lumber From Logs – How To
Lumber milling how-to; step-by-step from logs to lumber for your projects
Making lumber for yourself, a key piece of which is lumber milling, might be the solution you seek. Perhaps you have acquired some logs; the power company might have been clearing their lines, trees were toppled in the woods by high winds or a tree was threatening your home or other structure, the fruits or nuts were a problem, you are clearing property for a new home, or you are purposefully felling trees for a project. Regardless, the point is that you now have a potentially valuable commodity on your hands. What is to be done to realize that value? Lumber milling might be the answer, and that is the subject of this post. I'll assume that you don't have an Alaskan chainsaw mill tucked away in your garage, or a portable bandsaw mill out in the barn, though even if you do this post might be of service to you.
Lumber Milling Overview: Step By Step
Step 1: Log Preparation
Cut the logs to length
The length is based on your lumber needs. If you are looking for 8 ft long stock, cut the logs to 9 ft to allow for potential loss at the ends due to checking (i.e. cracking). Most Alaskan chainsaw mill set-ups will be able to handle up to 8 to 12 feet in length, our Wood-Mizer Super Hydraulic can handle 20 feet You will want to cut to consistent lengths so as to facilitate ease of stacking the lumber later; as an example you can plan to have a stack for 9 foot boards, and another stack for 11 foot boards, and so on.
Remove Branch Butts
Cut off branch butts as close the bark on the main stem (trunk) as possible; this makes for easier movement of the logs to the mill, and easier/faster log handling on the mill.
Select a location for the log pile and lumber milling
Unless you have heavy equipment, it's important to set yourself up for success from the start; logs are themselves heavy and difficult to move far by hand. Our truck and trailer combination is just under 50 ft in length, and the mill loads on the driver's side. These details become important, so if in doubt, you may want to call your lumber mill or portable sawmill service near you to clarify the situation. And as I tell all of our customers, short of a site visit pictures are the next best thing.
Get the logs off the ground if possible
Ground contact will result in faster decomposition of the logs and therefore less usable lumber. Unless you have milling organized in the very near future, cut some 3 or 4 inch diameter poles, or use some 4x4's to create space between the logs and the ground. This also makes for easier movement of the logs to the mill.
Clean the logs of mud, gravel, sand, and the like
This is a detail, but one your Sawyer will thank you for. As logs are skidded (i.e. dragged) across your property, the bark will pick up and hold all sorts of debris. This debris will at worst damage a blade or chain beyond repair, and at best it will shorten the life of the blade or chain. You can broom clean them, hose them off, use a pressure washer or compressed air; taking all necessary safety precautions of course.
Paint the Ends of the Logs
After being cut to length, the logs will dry through the ends faster than they will dry through the bark; this will cause unnecessary checking, i.e. cracking, in the ends of the logs, potentially costing the customer usable lumber. The industry standard for this application is a product called AnchorSeal, but in a pinch latex paint will do. Also consider using different colors for different species of wood; once the logs have been milled it can be difficult to differentiate one species from the other and the color-coding is helpful.
Step 2: Stacking and Drying Rough Cut Green Lumber
Let me say at the outset that drying of lumber is a science unto itself. Having said that though, there are some "rules of thumb" that will provide a useful starting point for our efforts. Most customers will begin with air drying the green lumber, and this is beneficial for at least a couple of reasons: 1) air drying has the lowest capital costs, 2) air drying helps to conserve wood, and thereby the timber resource, by reducing loss of product from drying degrade in a kiln, and 3) it's environmentally friendly in that it reduces the need to burn fuels for energy to dry lumber in a kiln, conserving those fuels and reducing environmental pollutants. Assuming time allows, it most often makes sense to air dry lumber exclusively if practical, depending on the future use of the lumber, or in preparation for final drying in a kiln. For our purposes we will look at the steps required to air dry either in preparation for kiln drying or as a standalone process.
Lumber Sorting
To facilitate stacking and drying, sort the lumber coming off the lumber mill by thickness, species, and length. Sorting by thickness is key, especially if you have kiln drying in mind; drying time increases at a rate of approximately the thickness raised to the 1.5 power. This means that 2-in. thick lumber will require about three times as long to lose a given amount of moisture than will 1-in. thick lumber. Quarter sawn lumber has unique properties that make in valuable in a number of applications, it does however require longer drying times. Check out our post on how quartersawn lumber is made.
Locate the Lumber Drying Stack
Avoid locating the stack near a body of water, be that a lake, pond, river or stream; such a location will slow the drying process. If you have access to heavy equipment it can be much easier to move a pile built near the milling location to the drying location. Good air flow is required to achieve the shortest possible drying times, so if the location is outside consider the prevailing winds and orient the long side of the stack perpendicular to the direction the winds will come from.
Build a Foundation
We are really after two things here, adequate support for the lumber pile, and sufficient gap between the boards and surface (ground, slab, etc.) to allow for the necessary air flow below the stack and fork access. Commonly 4x4's or 6x6's are used to form a foundation, pallets are another possibility. I usually suggest that the pile be no more than 4 ft wide, especially if you will be moving it using heavy equipment. The 4x's or 6x's will be in ground contact, so use pressure treated lumber if you expect to reuse the foundation materials. The surface does not need to be perfectly level, but it does need to be as close to perfectly flat as you can make it; the boards will assume the shape of the foundation they are drying on. To support a 4 ft x 8 ft pile, five 4 ft long 4x4's or 6x6's would be required, separated by 2 feet.
Acquire or Make "Stickers"
Stickers separate the courses, or layers, of the stack, allowing for airflow above and below the boards; stickers also carry the load of the pile to the foundation; and stickers near the ends of each course, or layer, may reduce checking, splitting and warping. Typically these are 1x1 or 1x2 material; the length being equal to or slightly greater than the width of the stack. Stickers can be made from the logs being milled, or inexpensive (cheap) 1x material can be purchased from your local Big Box hardware store or lumber yard and cut to length. Stickers that have been thoroughly dried perform better than green stickers made on site. Sticker length is again determined by pile width, so 4 ft for our hypothetical 4x8 ft stack. The stickers should be in vertical alignment with the foundation timbers.
Height of Lumber Stack
If you are using heavy equipment to move the pile the height of the stack will probably be limited by the lift and carry capacity of your equipment. If you are building the stack using manpower the height will be limited by the height at which boards can be placed upon the pile comfortably and safely. If the you will not be moving the stack and you are not putting boards on it manually, then stack height can approach 15 feet. Consider the stability and safety of such a stack.
Provide for a Lumber Stack "Roof"
If you will not be drying the green lumber in a shed or barn, pile (or stack) roofs can protect the lumber while it dries and reduce losses due to cyclic exposure to water and sunshine. For roofing material you can use roofing paper laid directly on the top course of lumber and weighted, exterior grade plywood, sheets of galvanized or aluminum roofing, or some combination of the above. The "roof" should overhang the ends and sides of the lumber drying stack; while still allowing air flow through the ends and sides of the stack. A sloped roof is preferable as the roof will better shed rain water and snowmelt.
Like I said, drying lumber is a science. If you want all of the gory details, check out the 66 page publication "Air Drying of Lumber" from the USDA Forest Service, Forest Products Laboratory.
Step 3: Stay Safe and Get Help
Stay Safe
Without question the most dangerous parts of the lumber milling process are log and lumber handling. Both logs and lumber can be very heavy. Logs in particular can move unexpectedly. You will want to wear appropriate shoes or boots, and gloves. Mind your hands and feet while working around the mill and the log pile. Getting a part of your body between a heavy log or slab (the irresistible force) and the sawmill (the immovable object) is bad news. Stay aware of your surroundings. Optional are eye and hearing protection; I wear both.
Get Help - Log and Lumber Handling
If you hire a Sawyer you won't be paying him minimum wage. Keep him at work milling, which means having in place help with moving logs to the mill and removing and stacking lumber from the mill. On longer jobs general clean-up of off-cuts and sawdust piles is also necessary. When making plain sawn lumber with the Wood-Mizer I can easily keep two to three helpers busy, anything less than two and you will definitely be slowing the process, at a cost of time and money. If necessary and only upon request, we can bring help to your location.
Get Help - Sawmill Service
And finally, get help with the milling. This is of course our bread and butter, so please reach out to us if you are within our service area for more information. In addition to a standout milling service, you will receive all of the coaching you desire in working through the process I've laid out, and to a memorable milling experience. If you will not be working with Primal Woods, please visit my Blog post on the subject of finding and working with a local sawmill service provider in your area.
To see how this all of the preparations mentioned unfold in reality, check out the video below. To organize the work with Primal Woods (see our service area below the video), email john@primalwoods.com, or call 269-222-0101.
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Well informed clients make for better customers. Simple, common sense communication is best. Great job John!