Posts Tagged ‘file’
Sharpening hand saws is intimidating for most people, but there are some readily available options that simplify the process greatly. Here’s a quick overview:
Angles: Before sharpening, you need to determine the angles you want to file into the teeth of your saw. The rake angle is the angle between the face of a saw tooth and an imaginary line perpendicular to the baseline of the saw teeth seen when viewing a saw from the side. It is generally 12 to 15 degrees on a crosscut saw and 0 to 8 degrees on a rip saw. You also need to control the fleam angle, the angle that is filed across the face of the teeth, creating a knife edge that slices wood fibers when cutting. On crosscut saws fleam typically ranges from 15 to 25 degrees, rip saws typically have little to no fleam. (read Understanding Western Handsaws for more info)
Control: Once you know the angles you want to create, holding a file consistently and accurately for dozens of teeth in a row is tough. Fortunately, there are several options available to you that make saw sharpening fairly straightforward.
Option one is to make your own file guide. I picked this up from Ron Herman’s DVD and it works great. I made my guide out of some scrap cherry in about 15 minutes. The pictures will help explain the details, but the idea is to hold the file handle in your dominant hand and the file guide (with the tip of the file buried in it) in your off hand. Hold the file level and the edge of the file guide perpendicular to the saw plate. If you can do this, the guide will control the rake and fleam angles for you, it’s easier than it sounds. (You may notice my guide is using a 30 deg rake and fleam angle, this is fairly steep for both but it was deliberate for this saw. You typically want something closer to the angles listed above.)
So this guide works well in a pinch, but if you have several saws to sharpen you’ll quickly realize you need a new file guide for every angle combination you want… this may only mean making 2 or 3 guides, but for others it would mean making many more. So for all your file guiding needs there are a couple adjustable file guides you can purchase. A reasonably priced option was recently released from Veritas and functions along the same principles as the wooden block, but you’ll notice a variety of angle combinations and file sizes can be accommodated with this single device. A second option from Blackburn Tools gives you the same functionality, but in a much classier package and at a premium price.
I have not purchased a file guide from Veritas or Blackburn so far, but I have more sharpening on the horizon so I intend to shortly. Hopefully this gives you the confidence to pick up a saw (preferably a cheap one that you won’t mind practicing on) and get sharpening. It’s really very simple and Ron’s DVD, as well as various free videos from youtube and Lie-Nielsen, will provide you with all the information you need.