The Bandsaw - Canadian Woodworking Magazine

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The Bandsaw



SAFETY TIP
The bandsaw is one of the safest machines designed to cut wood. Because the blade moves downward into the table, there is no tendency to lift up your workpiece, so kickback is non-existent. Compared to the tablesaw, mitre saw and radial arm saw, the bandsaw is supreme for safety. A few precautions are nevertheless important, since any cutting machine can result in injury.
 
1. Set the blade support assembly just ⅛” or less above your workpiece. This prevents your fingers from getting into the blade area.

2. Use extreme caution when your fingers are close to the blade. The table throat insert, which is the round metal plate your blade goes through, should be considered a safety zone. You rarely need to put your fingers within that area at all. If you do, use a push stick.

3. Be careful at the end of a cut when the blade exits your workpiece. People sometimes get injured at this point, not realizing that the blade is about to become fully exposed. Even if you are an inch away from exiting, you could suddenly reach a softer (less dense) area of wood, which allows you to lunge forward at greater than normal speed. Exercise extreme caution at the end of your cut or use a push stick.
 
PRECISION TIP
A bandsaw rarely leaves a super smooth finish, so you are usually going to joint, plane or sand the cut to get a finish-quality surface. However, there are still a few issues that are important for accurate results.
 
For example, your cuts should be 90 degrees to the bandsaw table. Assuming your blade tension is set correctly, the cutting angle is determined by how the table is set relative to the blade. The table tilts to make angled cuts, but it must be 90 degrees to the blade most of the time. Do this by setting your blade guide assembly as high as possible, exposing a long portion of the blade. Then, set a square against the flat part of the blade (not the teeth) and table. You can loosen the table locking knobs underneath and tap the table into perfect alignment. Check this adjustment before important cuts.
 
Your blade should also be 90 degrees to the table at its back edge. Check this by placing your square along the back of the blade and the table. You will also know how accurately your blade is set by watching the blade exit the back end of your workpiece, particularly on a very thick piece. Assuming the back end of your workpiece is cut 90 degrees to its surface, the blade should exit evenly from top to bottom. This isn’t so important for most cuts, but can be crucial for other operations. Every time you need to stop a cut at a certain place, such as while cutting the cheeks of a tenon, the cut must stop 90 degrees to the surface.
 
The back of your blade should be very close to 90 degrees to the table already, as this is part of the original design of the machine. If it is off a bit, you can tweak it by changing the tracking of the blade. There will be a tracking adjustment knob at the top of the saw. Adjusting it slightly moves the blade closer to the front or back of the two wheels, which changes the vertical angle of the blade. Unplug the machine and adjust the tracking by turning the wheels by hand.
 
Finally, the thrust bearings located just behind the blade, both above and below the table, should be set very close to the back of the blade. Ideally, they will not turn when the bandsaw is running, but should start to turn the second you start cutting. The recommended distance is usually the thickness of a piece of paper. If the gap is too large, there will be no support directly behind the blade as you cut. The result is a flexing blade that can never cut exactly 90 degrees to the table.
 
QUALITY TIP
As mentioned above, a bandsaw rarely leaves a smooth surface. But there are different degrees of roughness. For fast cuts, where quality of cut is unimportant, use a skip toothed blade or hook toothed blade. Both have larger gullets between teeth than a standard tooth configuration, giving a faster but rougher cut.
 
If quality of cut is most important, as when cutting joinery, a standard toothed blade is ideal. It has smaller gullets and a 0 degree hook angle. It might bog down in thick lumber, but gives the best quality cut.
 
There is a lot of talk about resawing on the bandsaw and getting a good quality cut. Keep in mind that the finished surface will never be smooth enough to use straight off the saw. Usually jointing or planing is the next step, so you should be aiming for an accurate 90 degree cut with reasonable speed. A hook toothed blade is best, but a skip toothed one works well too. And although wide blades like ¾” are usually recommended, I find that most 14” bandsaws (the most common size) are underpowered to handle a wide blade in 6” thick hardwood. Using good blade tension and a sharp blade, I find that even a ¼” or ⅜” wide blade does a great job.
 
That takes us to one final point. Each time you change your blade, you have to reset the blade guides, thrust bearings, tracking, etc. for optimum results. Due to the time consuming nature of these adjustments, it’s best to choose one blade that can handle most operations. You’ll find a ¼” skip toothed blade in my saw most of the time and it handles anything from tight curves in thin stock to resawing 6” thick hard maple. Most of my joinery is handled using other machines, so I’m looking for efficiency and accuracy, but not so much surface quality. Other machines take over to refine the surface afterwards.
 
Next issue Hendrik gives three tips on using your drill press.



Hendrik Varju
HENDRIK VARJU is a fine furniture designer/builder who provides woodworking instruction and private seminars near Acton, Ontario.
(519) 853-2027
www.passionforwood.com