| Workshop Tour, Part 2 -- Band Saw Tune-Up |
From "Wood Works"
episode WWK-413 |
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In this segment, David Marks discusses one of the most essential tools for the workshop -- the band saw. He also provides tips on maintaining and tuning this important tool.
Review: The Top Four Essential Tools for the Woodworking Shop
- Planer
- Jointer
- Band saw
- Table saw
The Band Saw: Tune Up and Maintenance The 14-inch band saw (figure A) is one of the most useful tools in David's shop. This is the most common size for this essential tool. The one in David's shop was purchased used 25 years earlier. He added a large platform to make it easier to work with larger pieces of stock. This setup makes it possible to cut small, intricate curves even on larger pieces. Another modification that David added to this tool is a 6-inch riser (figure B) making it possible to cut stock up to 12 inches wide. When purchasing a used band saw, it's a good idea to conduct a thorough tune up immediately after it's purchased. This is a precision cutting tool, so the time spent in fine-tuning is well worth the effort in terms of the quality of the final cuts. Following are - First, replace both bearings (figure C) on the top and bottom wheels.
- Next, balance the wheels. David achieved this by adding wire to the wheels for weight (figure D). This process is similar to balancing the wheels of a tire. Add a little weight at different locations until the rotation is true.
- Check the condition of the tires -- the large rubber band that wraps around the wheel (figure E). If it is worn, dry and cracked, it should be replaced. Use an adhesive that will bind rubber to metal.
- If you replace the tires, you'll need to true them so that they are concentric to the shaft. The tires may have imperfections, and be thicker in some areas than others. As the wheel turns this variation in thickness can effect the blade, causing it to move back and forth. The resulting vibration will produce a rough cut. To prevent this situation, true up the tires by sanding them. David achieves this by means of a truing kit he custom-made (figure F).
- The truing kit is attached to the saw. Sandpaper is attached to an adjustable lever that applies pressure to the wheel as it turns -- sanding the tire concentric to the shaft (figure G). Talcum powder added to the sandpaper surface will prevent rubber dust from sticking back onto the tire.
- Another of David's homemade options is a small wire brush positioned so that it's in contact with the wheel (figure H). This prevents sawdust from collecting on the tire.
- With the wheel balanced and re-tired, the next step is to replace the blade with a new one. Around 60 percent of a good cut can be attributed to the blade. David advises using a high-quality, sharp bimetal blade with 6 teeth per inch and a hook configuration (figure I). A bimetal blade will cut through metal as well as wood.
- Before installing the new blade, clean away the manufacturer's grease using naphtha or paint thinner. To increase the life of the blade, it's advisable to spray it with a dry lubricant. The lubricant will reduce friction, heat and metal fatigue.
- To install the blade, loop it around both tires, and through the guides, making sure that the teeth are facing down.
- Adjust the blade tensioner until the tension spring is nearly compressed (figure J). Use caution, however, because if the tension is too tight, the blade may "walk" off the tire during operation. Strive for a blade deflection of no more than half an inch.
- The tracking adjustment will center the blade in the middle of the wheel (figure K).
- Next, support the thrust bearings so that they support the back of the blade (figure L). You'll need to adjust both the upper and lower thrust bearings.
- Adjust the upper ball-bearing guides. Using a dollar bill as a shim (figure M), tighten the bearing snug against the blade so that the position of the bearings are behind the gullet of the tooth (figure N). Repeat this adjustment on the lower guide bearings.
- Tip: Most band-saws come standard with metal guides. You may want to consider replacing them with wooden ones made from lignum vitae or metal ball-bearing guides like the ones on David's saw. The objective is to reduce friction.
- Once the bearing adjustments are complete, use a silicon carbide stone to grind the back of the blade (figure O), rounding the corners slightly. This is another method of reducing friction and will help prevent drag.
Band Saw: Adjusting for Blade Drift
The final phase of the band-saw tune-up is to adjust for drift. Unlike table saws, band saws possess a nuance called drift. This term refers to the fact that every blade has a tendency to cut slightly in one direction or the other. Fortunately, the drift for a particular blade remains consistent throughout the life of the blade. Therefore, the fence on the band saw can be adjusted slightly to compensate for that angle.
- The first step is to determine the angle of the drift. Use a jointed piece of kiln-dried stock that is 24 inches long by 2 inches thick. Draw a line down the length of the stock 1/8-inch from the jointed edge (figure P).
- Use the band saw to freehand a cut along the line, stopping a third of the way down the length. Set the sliding bevel gauge against the jointed edge and lock in the angle. Continue cutting along the line, occasionally checking the angle with the bevel gauge to confirm the angle of the cut (figure Q).
- Once you've determined the exact angle, adjust the fence on the band saw to that angle. The angle can be adjusted by first loosening the bolts beneath the front of the fence (figure R).
- Once the bolts have been loosened, tap the fence gently until it lines up with the bevel gauge to get the proper adjustment (figure S), then re-tighten the bolts.
- This adjustment should ensure straight cuts -- until you change the blade. Setting the blade to compensate for the drift is the most important step in fine-tuning a band saw. Once the adjustment is set up, you'll be able to slice off thin sheets of veneer with confidence.
Band-Saw Tune-Up Checklist
- Balance the wheel;
- Change the rubber tire;
- True the tire;
- Adjust guides and bearings;
- Grind the back of a new blade;
- Set the fence to adjust for drift
In the segment that follows, David Marks provides expert advice on caring for the most important of tool in the workshop -- the table saw.
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RESOURCES :
Fine Woodworking
A magazine devoted to high-quality craftsmanship in woodworking.
The Taunton Press Inc.
Website: www.taunton.com
The Small Wood Shop (The Best of Fine Woodworking)
Author: Helen Albert (Editor)
Publisher: Taunton Press
ISBN: 1561580619
Woodworking Techniques: Best Methods for Building Furniture from Fine Woodworking
Author: Editors of Fine Woodworking magazine
Publisher: Taunton Press
ISBN: 1561583456
Mastering Woodworking Machines (Fine Woodworking Book)
Author: Mark Duginske
Publisher: Taunton Press
ISBN: 0942391985
David Marks Website
David Marks, DIY's Wood Works host, is a master woodworker. For more information on cut sizes and project details, please contact him via his Website at www.djmarks.com
How to Design and Build Your Ideal Woodshop
Model: 1558704817
Author: Bill Stankus
Popular Woodworking Books
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