Re: Hand saw sharpening question
L. Hanson - N. Idaho
>Here's a part of a thing I'm working on for my website, maybe it will help:
If you are having difficulty starting the cut, here's probably why:
First off, a freshly sharpened saw is harder to start than a dull one. The cutting edge of sharp teeth are going to grab the wood much more than a dull one would. One experience with saws actually looks for this, because if it's not there it's a sign the saw is dull or at least starting to get dull. Practice makes a great deal of difference in being able to start saws easily.
Figure A shows a normal saw at the start of a cut. The corner of the stock being cut protrudes into the teeth, forcing the saw to take too big of a bite. After the saw gets going, the angle is closer to that of the saw, and the teeth can then take light shavings off instead of a big chunk, similar to what you see in Figure B.
To start the cut easier, there are three things to try - first, you can try pull the saw towards you to start the kerf, which will start a shallow cut by breaking through the corner of the board. In Figure B - you can see the reduced angle of both the teeth in the pull direction, and in the stock after the initial cut has been made. What you've done is changed the effective angle of the cut, lessening the bite the teeth need to take.
Pulling the saw can cause a bit of tear-out at the corner. If that's an issue, score the cut first with a utility or marking knife.
A second alternative, shown in Figure C is to can lower the angle of the saw. The lower the angle, the easier the saw will cut. Be careful you don't go too low, as it can be awkward and possibly cause a bit of tear-out.
A third option is to lift about half of the weight of the saw off of the board for the first cut or two. This obviously does not change the cutting angle - what this does is provide a check against your technique. Many times you are simply trying to force the saw too much, putting too much weight behind the cutting motion - which causes the teeth to dig into the wood, making it harder to start the cut.
You can use either any single or combination of these methods to help get the saw started in the cut.
If you've gone through all the steps outlined above and are still having difficulty, you may have the saw sharpened with too steep of a rake angle. You might need to go back and re-sharpen your saw using a less aggressive angle that starts easier. Be warned, easing the rake angle will make the saw easier to start, but at a cost in performance - the saw will not cut as fast. Also, if you just sharpened the saw, it can take a little while, but as the saw begins to dull, it will get easier to start. The razor sharp edges on a freshly sharpened saw don't always last that long, but that doesn't necessarily mean the saw is dull. It may be that a little patience will bring about the results you desire.
Leif
Norsewoodsmith.com