10 Tips for Better Precision in your Woodworking
By Luther Shealy
Tip #1: Use Accurate Rulers and Measuring tapes.
You should have at least one high quality, 12-inch steel rule that is thick and finely etched. If you have a high-quality combination square such as a PEC or a Stanley you can use it’s ruler, but I find it more convenient not to remove the ruler from the head of my combination square when I need a ruler so I have a high quality, thick steel ruler from PEC. Use this ruler as your shop standard and make sure all your other measuring tools match it. Check all your rulers and tape measures against this standard. Get rid of the ones that do not measure up.
I find it helps significantly to purchase rulers and tape measures from the same manufacturer. Additionally, I find that tape measures are the most likely to go out of accuracy so check them often. Pay special attention to the hook. It is supposed to move, but it can get worn out over time and move too much.
Tip #2: Use the Right Tool to Measure.
Your steel ruler will give you more accurate results than your tape measure, so use it when you can. For me this means that when measuring anything under 12-inches I reach for my steel ruler. I use my 6-inch steel ruler for measurements less than 6-inches.
I also use ruler stops (I use woodpecker ruler stops but there a lot of others out there) that fit on my steel rulers. I find ruler stops help significantly when taking measurements.
Anything over 12-inches I reach for my tape measure.
Tip #3: Do Not use Rulers
Yes, you heard me do not use a ruler. When you can, show the stock you are going to cut to the work and make your marks on the stock. Using a ruler or a tape measure means you are automatically inducing some error because you must interpolate your reading to the nearest etch line, then translate that onto your stock. Remove all those errors by just marking your stock against your workpiece.
Tip #4: Make sure your Squares are Square.
Squares are absolute necessities for accurate work, but they must be dead on square. Check your squares about every 6 months and anytime you drop your square. Using the factory edge of a piece of plywood or an edge that you know is perfectly straight, hold your square’s reference face against the known straight edge and draw a line along the beam. Then flip the square over and align the beam so it is about a 1/8th inch from the first line and draw a second line down the beam. Carefully examine the two lines, they should be parallel. If not, your square is not square – do not use it.
Tip #5: Mark thinner Pencil lines.
When marking lines with a pencil, not any pencil will do. The most common pencil is the ubiquitous 2H or 2 HB pencils. This are soft lead pencils that leave a thicker line than a harder lead and they quickly wear out leaving an even thicker line. Instead go to an office supply store and get some 5H hard lead pencils. The harder lead sharpens to a finer point and holds that point longer. The line will not be as dark as a 2H but it will be more accurate.
Tip #6: Use a Knife Line Instead of a Pencil
When accuracy really matters put that pencil down and reach for a sharp knife. A knife line is more accurate than a pencil line and you should use them for all joinery cuts. I recommend a double bevel marking knife with a flat back. The flat back is held against your square’s beam while holding the knife in a vertical position. Use several light strokes to establish a line verses one or two stokes with lots of pressure. The knife can wonder with the grain if you use too much pressure.
When possible, I use a wheeled marking gauge instead of a knife. Make sure your marking gauge’s cutter is sharp. One of the biggest issues we see is dull marking gauges. Most marking gauges you buy do not come sharpened; you must sharpen them before use. If you don’t have a sharp cutter instead of a knife line you will get a crushed wood fiber line. (Note: All Rob Cosman Marking gauges are pre-sharpened and ready to use out of the box)
Tip #7: Learn to Use calipers:
Pick a pair of high quality digital or dial calipers and learn to use them. I prefer dial calipers as I hate changing batteries. Using calipers, it is easy to take inside or outside measurements to the nearest half-thousandths of an inch. Calipers will not replace your steel ruler, but when measuring thicknesses or opening size I reach for my calipers.
Tip #8: Use Stop Blocks on your Table and Chop Saw.
Never cut different boards that are supposed to be the same lengths, by marking a line and lining up the cuts individually. If multiple boards are to be the same length, then set a stop block on your fence and cut all your pieces to length using the stop block.
Tip # 9: Use shooting Boards and Table Saw Sleds.
These two devices are a must for any serious woodworker. They turn your table saw and hand plane into precision instruments that give you absolute square cuts. You must make them dead on square, but this is easily achieved by careful construction. On a crosscut table saw sled the fence must be 90 degrees to the saw blade / kerf. I use and recommend William Ng’s “5 cut square method” (Look it up on YouTube). On a shooting board the fence must be square to the plane track. Watch Rob’s YouTube video on how to make his shooting board.
Tip # 10. Start with Square Stock and Marked Reference Edges.
You must start out with dead-on square, flat, and true stock, or whatever error it is out will be introduced into your work. Whether you dimension your stock with machines, hand planes or a combination of both make sure you use your square, winding sticks, and straight edge to make sure your stock is flat, true, and square. (See Rob’s playlist on his YouTube channel which shows you step by step how to achieve this).
