Cutting Logs Into Lumber
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Helpful Information

 

To ensure that you get the most productivity from the sawmill, the wood lot and logs should be prepared properly.

 

Wood lot

A clear location is necessary to set up the sawmill.  The sawmill is 16 ft. long by 12 ft. wide after installing the ramps.  It weighs 2000 lbs.  Setup of the sawmill takes approximately 15 minutes.  The best location is parallel to the logs with the drying or trailer location near the back of the sawmill.

 

Logs

Fresh logs are easier to cut than old, dry logs.  Dirt and bark cause blades to dull prematurely.  Logs must be cleaned before cutting by sweeping them with a stiff bristled broom.  Power washing or cleaning with water can also help as long as it does not push the dirt farther into the bark.  The best condition is when the bark is removed, especially at the point of entry by the blade.  This is easily accomplished with some types of trees but not others.  All limbs will need to be removed before cutting.  All logs should be stacked parallel to each other so they can easily be rolled onto the ramps of the sawmill.  The ends of all logs should be coated to minimize checking.  Use of a commercial sealer like Anchorseal, Paraffin wax, beeswax, or oil based paint work well.  Latex paint is not recommended as being effective. 

 

Sawmill

The sawmill is capable of cutting logs 31 inch in diameter by 15 feet long.  The maximum board width is 24 inches and the minimum thickness is 1/16”.  It cuts using a bandsaw that provides more lumber than circular saw mills due to the thin kerf of the band blade.  Boards can be cut to one inch from the bed of the sawmill.  Ramps and a log loader are equipped to roll the logs onto the mill.  Logs over 31 inches in diameter will need to be cut in half before cutting into boards.  This can typically be accomplished by a tree cutting service.

 

Safety

Safety equipment must be worn when handling and sawing wood.  Gloves and safety shoes are highly recommended when handling logs and boards.  Safety glasses and hearing protection must be worn while the sawmill is in operation.  Use a cant hook to help roll logs.  Always use good posture to prevent back strains.

 

Sawing Methods

The final use of the lumber should be taken into consideration before cutting the logs.  All techniques start by cutting the log into a cube (cant). 

 

Construction

After or when cutting the last side of the cant, the width of the boards are set.  The boards are then cut to the desired thickness until the cant has been completely cut.

 

Plain or Flat

This is the easiest and fastest way to cut lumber.  The width of the boards is determined by the diameter of the log.  The boards are cut to the desired thickness until the cant has been completely cut.  Any boards with growth rings less than 45 degrees are “plain” sawn.  Some quarter sawn lumber will result using this sawing method.

 

Grade

Sawing for grade produces a high quality, high value lumber that has good dimensional stability.  This method also helps to provide stress relief in the log as it is cut.  It is typically performed on hardwoods where the wood is used for furniture, cabinet making, etc.  It is not normal to “cut for grade” when sawing construction lumber.  To cut for grade, 2 or 3 boards are cut from the top of a squared cant.  The cant is then rotated 180 degrees and the same number of boards are sliced off.  The cant is then turned 90 degrees and 2 or 3 boards are taken off.  Another 180 degree turn is performed and an equal number of boards cut.  The cant is rotated to the first side and the procedure is continued until the entire cant has been sawn.  The drawback to this method is that the boards are produced at various widths.

 

Quarter

Quarter sawing is the method used to produce the most stable, highest quality, most valuable lumber.  By definition, lumber with its growth rings oriented at 45°-80° to the face of the board is said to be “quarter sawn”.  If the growth rings are 80°-100° to the face of the board, it is defined as being “fully quarter sawn”.  To quarter saw lumber, the top 1/3 of the log is cut and removed.  The middle 1/3 of the log is cut into boards.  The bottom 1/3 of the log is then rotated 90 degrees and cut into boards.  The top section is then reloaded onto the sawmill and cut into boards in the same manner as the bottom section.

 
 
  

Foreign Objects

Foreign objects such as metal, nails, wire, glass insulators, etc. will ruin a saw blade and create a safety concern.  Any logs that may contain foreign objects will be checked with a metal detector before loading them on the sawmill.  A decision will then need to be made as to whether or not to salvage the log by digging the foreign objects out or setting the logs aside.
 

Air Drying Lumber

Most species of newly felled logs have a moisture content of 60% - 100%.  When lumber is air dried it reduces the moisture content to 12% - 20%.  Shrinkage occurs when moisture content is reduced below 30%.  Therefore, some shrinkage has already occurred when lumber is air dried.  Lumber for interior use (furniture, flooring, trim) must be dried to a moisture content of 6% - 8%.

 

For air drying lumber follow these guidelines:

 

·   Most drying rapidly occurs in the first few days.  It is recommended that you “sticker” the lumber immediately after sawing.  Stickers are small strips of wood about 3/4” square (they can be as wide as 1 1/2”).  Stickers are placed crosswise between layers of lumber to allow air flow between the boards.  The stickers should be about 2 ft. apart.  Take care to line the stickers vertically so there is an even distribution of the weight.  Add rocks or heavy timbers to the top of the stack in order to keep the top layer flat.  Protect the lumber from rain, snow, and sun by covering the top with overlapping slabs (as you would shingles on a roof) or cover the top with a sloping piece of plywood or aspenite.

 

·   Do not cover the pile with plastic sheeting.  This holds in moisture and produces condensation.

 

·   All the boards in the stack should be of the same length.  Short lengths can be pulled to opposite ends of the pile (see the following illustration).

 

·   Stickers should be of the same species or light colored to prevent staining.

 

·   Position lumber stacks to take advantage of prevailing winds.  The air should flow through the sides of the piles.  Separate the stacks by at least 40 inches.

 

·   Keep lumber at least 6 inches off the ground by setting it on spare timbers or blocks.

 

·   End checking can be minimized by coating the ends of the boards with a commercial sealer like Anchorseal, Paraffin wax, beeswax, or oil based paint.

 

·   In general, hardwoods will take twice as long to dry as soft woods.

 

 

Drying Lumber Indoors

After air drying is complete, small amounts of lumber can be dried in your home to bring the moisture content down to 6% - 8%.  The lumber must be stacked in the same manner as outdoors air drying.





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