Consistent care and maintenance is necessary to ensure your tool's peak performance for many years to come
If you are like most woodworkers, spending your time doing maintenance on your machinery probably falls to the bottom of your "to do" list. Yet in order to produce quality work, your machinery needs to perform to the best of its capability.
Maintenance boils down to three main categories: keep it clean, calibrated and lubricated. Do these tasks periodically and your machines will provide years of good service.
In this article, we will look closely at the table saw â€” specifically a cabinet saw.
Keep it clean
Keeping your saw clean begins with good dust collection. With the exception of the recently designed SawStop, most cabinet saws are notorious for allowing dust to accumulate in their bases. Good dust collection not only keeps dust away from moving parts in the saw's base, but also makes for happier operators.
If your saw is equipped with an overhead blade guard â€” and it should be by OSHA standards â€” a secondary dust collection source at the guard will further reduce the amount of dust distributed around the saw.
Oftentimes, thin strips will accumulate at the dust port or in the flexible connecting hose, causing sawdust to build up in the base. Periodically check to see that this isn't occurring. Excess dust can also accumulate around the motor, causing heat to build up, potentially shortening the motor's life or even causing it to fail. Most motors today are TEFC (Totally Enclosed Fan Cooled), but that doesn't always prevent dust from working its way into the motor. Periodically vacuum the air intake or used compressed air to blow out the motor.
Aside from problems caused by dust, a saw's surface takes a lot of abuse during use. Resins from wood tend to accumulate, and humidity can cause the top to rust. Periodically treating the top with a surface sealer will inhibit rust and reduce friction, making it much easier to feed wood through the blade. There are a number of commercial spray products designed specifically for this purpose. Look for products that do not contain silicone because they can cause problems with finishing, especially if you use waterborne finishes. If the top has rust on it, use a rust remover and/or abrasives to remove trouble spots. Getting rid of rust as soon as possible will prevent the metal from more serious damage caused by pitting.
Keep it calibrated
This is probably the biggest and most challenging category of items to attend to on a table saw.
First, let's start with the fence. Is it cutting accurately? Are you having problems with the blade healing? Is the blade cutting unevenly? This is caused by the fence not being aligned parallel with the blade. By looking at the saw marks left on the edge of a freshly ripped board, you can usually tell if the fence is angled toward or away from the blade. Ideally, the marks should reveal the blade cutting evenly on the up and down part of the blade's rotation. If the marks reveal the saw is cutting primarily during the upward motion of the blade, then the fence is angled toward the blade. This is least desirable and can often result in kickback. Boards that primarily reveal marks on the down rotation indicate the back of the fence is angled away from the blade.
Some operators prefer to deliberately angle the fence away from the blade to help reduce the chances of kickback. Angling the fence away from the blade a few thousandths of an inch over the length of the fence is generally sufficient. Measuring .005" is best accomplished with a dial indicator. There are a number of companies that sell specialized diagnostic tools for the table saw and other woodworking machinery. While their products often make calibration tasks easier, I recommend purchasing a simple dial indicator and spending your money on a copy of John White's book, "Care & Repair of Shop Machines" (Taunton Press). His book clearly illustrates the most important things to look for on most major shop machinery.
In addition to checking the fence for calibration, other key items include checking the blade's angle to the table, alignment of the throat plate and extension wings with the table's surface, alignment of the splitter or riving knife with the blade (another OSHA-required item), and alignment of the miter gauge slots with the blade. In order to accomplish the last item, the bolts that attach the top to the base must be loosened. At this point, it's probably worth taking the time to remove the top to check and lubricate the saw's trunnions and adjusting gears. If you've never done this before, it may seem like a daunting task, but it's really not a big deal and should be done at least once a year. Remove the blade first, and be sure to get help lifting the cast iron top off.
Removing the top gives easy access to the inner workings of the saw. By taking the tension off the belts, you can check the arbor bearings for excess wear. Check for any play, then rotate the arbor 90 degrees and check again. You can also use a screwdriver to listen for any internal problems. Put the end of the screwdriver on the casting surrounding the arbor bearings and rotate the arbor while resting your ear on the handle of the screwdriver. If the bearings make a clicking sound, the arbor should be pulled and the bearings replaced. With the tension off the motor, check it as well to make sure the pulley rotates freely and that it is aligned with the arbor's pulley. Finally, inspect the belts for wear before retensioning.
Keep it lubricated
The major challenge with lubricating woodworking machinery is that most lubricants attract dust. However, without lubricant, metal-to-metal contact would quickly cause parts to wear. Newer Teflon based lubricants are less sticky and help reduce this fatal attraction.
Most saws do not require having the top removed to lubricate the trunnion assembly, but doing so makes access much easier. Prior to lubricating the worm gears and trunnion surfaces, use a degreaser to remove any existing dirt and grime. Traditionally, White Lithium grease was recommended for lubricating gears and heavy contact surfaces, but I've found newer Dry Moly (Molybdenum) lubricants work better and have less of a tendency to attract dust and dirt. Thinner-penetrating lubricants can be used to grease hard-to-reach areas like the blade raising and tilting rods where they pass through their support bushings.
Monitoring the items mentioned above will ensure your saw is operating at peak performance and will help to keep your saw running trouble-free for years to come.
Keeping a maintenance log is also recommended to record the dates maintenance was performed and which lubricants were used.
Patrick Molzahn is director of the Cabinetmaking & Millwork Program at Madison Area Technical College in Madison, Wis.