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Sharpen a Rip Saw: 1 | Joint and File

Updated: Apr 26

I learned saw sharpening from Mark Harrell. You may know him as the Founder of Bad Axe Tool Works. Not long ago, he handed that company off to his former employees.


Today he's running Saw Sharp, where he restores and sharpens saws for customers as well as teaching woodworkers to do the same for themselves.


Years ago he was kind enough to invite me to demonstrate at one of those seminars. First he taught us to sharpen a back saw and then I got to speak about cutting the BIG joinery needed to make a workbench by hand.


But that's a different blog post.


I'm sharpening a panel saw here. The teeth and files are bigger, but the principles and geometry are basically the same.


Remove the handle

Before you sharpen a saw, you should separate the handle from the plate. If you have split saw nuts, you'll want to take a look at getting the correct driver from a tool maker like Lie-Nielsen. My saw has standard slotted saw nuts so, with a little care, I can use any driver that will fit in the slot.


I also quickly learned that it's easier to pop the female side of the nut out of the handle before you separate the two halves.


Place the saw plate in the Saw Vise

If you missed the making of the Saw Vise, you can find it here.


Mark the teeth

You want to mark the teeth that lean away from you on both sides of the plate. Since the teeth lean in alternating directions, you'll be marking every other tooth and only one side of each tooth will get marked.


Joint the tooth line

This step serves two purposes.


First, it keeps the tooth line straight. This allows you to make a stop cut and know that the cut depth inside the kerf is the same as it is where the saw exits the work.


Second, the flats created by the file give you a guide to file by. They get smaller as you approach "sharp". When they're gone, you know you're done.


The teeth of this saw followed a pretty strong arc. I had a lot of material to remove in the center. More material than I really had time for. In the end, I decided to aim for straighter instead of perfectly straight. Each time I sharpen I'll bring the tooth line a little closer to true.


Protect Yourself

Personal protection is a MUST here. You're going to be making some pretty fine metal swarf as you file.


Fine enough to float in the air.


Long enough to get into your lungs.


And once it gets into your lungs, it doesn't come back out.


So, please, wear a mask.


And be sure to protect your eyes too. If you need to touch your face during this process, stop and thoroughly wash your hands first.


File the teeth

I'm using a 7 inch Slim Taper file for this 5-1/2 TPI saw. Each face of the file should be twice as wide as the back of a tooth. This is because you'll be cutting both the front and back of the tooth with each pass. You don't want there to be any overlap of used surface as you rotate the file from one corner to the next. You can get by with a file that's a little too big, but you'll be putting wear and tear on the entire file if use one that's too small.


As I try to explain this in writing, I'm realizing I may need to make a video.


And maybe some props...


Back to filing.


Wiggle the file into place on the back of a dotted tooth (it should be leaning away from you) and get ready to file.

Mark taught us to use a combination of strokes that went light, heavy, light. The first stroke is all about getting the file in line to match the existing tooth geometry. So it's important to stop and check your work. If you get it wrong, make an adjustment and take another light cut.


Once everything's lined up, you can make a heavier cut and remove the bulk of the material. Follow with a final light cut to polish the the surfaces a bit.


Use the width of the flats from the jointing step as your guide. You will only be filing the back and face of half the teeth with the first pass. You'll have to flip the saw to finish the job. You do, however, change the width of every flat with each cut. So you want to aim for reducing the them to about half their original size. Take less than you think you need if you're not sure.


Once you've finished your first pass down one side of the plate, flip the saw and repeat the process on the other side. This pass should remove almost all the remaining flats on the teeth.


Flip the saw and take a few light cuts where needed on the first face. Then flip it again and repeat the process.


Once the flat on a given tooth is gone, don't touch it again.


This saw required A LOT of jointing. So the flats were pretty wide in the center. I had to be patient. I ended up making three passes on each side.


Clean your files

If you don't have a file card, order one when you order your files. I've got links to both down below the video.


Next Steps

I ran out of time as I was finishing up the filing. There are a few more things I need to do before I can put this saw to work.


I'll cover that in the next post.


 


Appearing in this video:



Items noted with an asterisk (*) are affiliate links. You'll pay the same price and support my work when I receive a small commission from the retailer.



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