Hi Skew,
Quote:
Maybe stupid question: When you are filing every other tooth set away from you, are you also filing the back of the tooth toward you at the same time? You emphasized not to flip the saw.
Not a stupid question at all.
This is a question that could require a book to answer.... You'd think the answer should be a simple one, but when we consider all the ramifications the answer entails, there is no simple, short answer, other than to say "yes" and leave it at that and let you file another fifty saws and still end up with different size teeth.
Let me say that 99% of the saws I file are not filed with the rake and fleam angles that I like to use. Talking crosscut saws. So my first pass will be to correct the angles. This often times goes for even a new saw. When I joint the tips of the teeth, they will invariably have some with bigger flats than others and sometimes no flat on some of the teeth. This means that the teeth are not all the same height. Putting it a different way, not all the gullets are the same depth. What we want is for both the same height and the gullets the same depth. Often times when I do that first jointing, every other tooth will have a bigger flat than the alternate teeth. This means they had been filed, leaving "Cows & Calves" or Big tooth, Little Tooth syndrome". Short of reshaping the teeth by filing straight across and filing the teeth to look like rip teeth, I will sometimes reshape the teeth while at the same time, correct the rake and fleam angles. This is where the answer to your question begins..... yes, I will file both the front of the tooth on the right side of the file and the back of the tooth that's on the left side of the file.... but.... if the tooth on the right side of the file has a flat and the tooth on the left side doesn't have a flat, I will file off all of the flat on the tooth that has the flat and will only file the tooth that doesn't have a flat enough to so I'm only filing just to it's tip. However, while doing this, you must maintain your rake angle. Sometimes a tooth will be so far off from what I want, when I file off all of the flat on the one tooth, I haven't filed the other tooth to it's tip. In this case, I leave it and skip the next gullet and file the next tooth. This time, both points on each side of the file might have a flat, one might be bigger than the other. In this case, I'll file half of the flat on both teeth, leaving the other half to be filed when filing in the opposite direction, from left to right. What I have just described is only an example. A poorly filed saw can have teeth with extreme differences. It becomes a judgement call whether to try to fix the existing teeth or do a complete reshaping and start over. If you have a saw that you can sight down the tooth edge length wise and it resembles a small roller coaster, you'll need to reshape the teeth. Reshaping will often times require multiple jointings and filing only the teeth with flats. In these cases, the teeth can be so much different in size, you'll only be filing the tooth with the flat and not the other tooth. Each time you joint, you will be filing more teeth than the prior jointing. Keep jointing and filing until you have flats on all the teeth. When you reshape in this manner, you are filing straight across, and you are maintaining the desired rake angle. So if you are reshaping for crosscut teeth, your rake angle will be 15* which is an angle that most of us filers use. Your last jointing should leave a very small flat on each tooth, less than 1/64".
After reshaping, set the teeth. After setting the teeth, file in the fleam angle. I like to use a 25* fleam angle for most crosscut saws for general purposes. When you file the fleam angle, start at the right and file the tooth set away from you and file every other tooth. When you do this first pass after setting the teeth, file both the front of the tooth bend away from you and the tooth on the left of your file which is the back of the next tooth until you have filed both teeth to a point. When you do this, you are filing all of the flat off of both teeth, the tooth on the right of your file and the tooth to the left of your file and be sure to maintain your rake angle. While you are doing this, the corner of the file is filing the bottom of the gullet, making the gullet deeper.
When you have filed every other tooth from right to left, do not flip the saw. Do not change your rake angle, merely angle the file handle toward the toe end and file the alternate teeth from left to right. At first, the teeth are going to look kind of weird. Now when you file, you will be filing the back of the tooth set away from you that will be on the left side of your file and the front of the next tooth that will be on the right side of your file. Maintain your rake and fleam angles and file each tooth so each tooth is to a point. When you do this, the teeth should be the same height and the gullets the same depth. Do a couple inches of teeth and you will see that they all look the same. Well, they won't be perfect, but pretty close. To get them closer to the same from tooth to tooth, after you have filed all the alternate teeth from left to right, do a very light jointing and make one more pass. Some of the teeth will have small flats while the file will have just barely touch other teeth. When you do this last touch up pass, file off only half of the flat on those teeth that have a flat, starting again on the tooth set away from you and file every other tooth. File the alternating teeth from left to right and file off the other half of the flats.
If you are filing a saw with relatively good teeth that are only dull, all you need to do is a touch up pass.
Do we have a book yet?
