A sharp tongue is the only edge tool that grows keener with constant use.
For the first filing, I like to take the handle off so I can re-finish it and also it allows me to clean up the blade. For this blade I had to file the wrecked teeth right off and start fresh, which actually takes less time than you would think. I stayed with the original setting of 12 tpi. I did find on the net a print out of lines that lets you sight different lines, that is to say sheets with 12 tpi, another sheet with 8 tpi etc.
Here are the lines. Just set it just behind the blade and file right on the line. I do a light scoring all the way down the blade so that when I get filing I can keep a rhythm going. Just file until you see a small flat on the top of each tooth. I will go more into my method of filing in a later post but I will say keep the flats as long as you can. Another thing I do is shut off the overhead lights and have only a swing lamp shining behind across the flats. This is critical.
Like I said, I will go into greater detail later, but the way I file a blade that is in pretty bad shape, one with misshapen teeth and different heights, is I sharpen right to left, heel to toe (handle to tip) first filing. Leave the flats, all you want to do is reduce then by half. I should have said that you must first joint the tops of the teeth to bring them all even, this is what gives you that flats. So anyway, joint and sharpen from right to left, heel to toe, cutting the flats in half. Then flip the saw around and file back the other way, left to right, still heel to toe, this time filing to shiny flats right off.
When you get to the end, turn the saw back around, and re-joint it lightly, very lightly. I then set the teeth, and joint again once. Now with the heel at your right, file lightly, to the toe, flip around and do the last filing, left to right, again heel to toe. This last one should take off the last glimpse of shiny flats and leave a saw that is sticky sharp.
These are the dovetails I cut with this saw, not bad for a big panel saw. Usually dovetails should be sharpened as a rip, or a modified rip, but this crosscut did ok.