A tenon saw and more sharpening fun…

Whenever I undertake a new woodworking project, I find myself needing to take breaks periodically due to spring steel withdrawal. You know what I mean…the ache you get in your loins for a freshly revealed etch and crisply sharpened teeth staring up at you from your vintage Disston saw vise?

No…you don’t get that feeling??? Hhhhmmmm….maybe my wife is right? Well, anyway….

It’s sad, but it seems I can’t go more than a few days without diving into some old saw rehab to bring another long-lost gem back from the brink of the scrap pile.

This week was wrought with said withdrawl….I’ve been knee-deep in my new super saw bench build…ripping, planing, cutting…actual WOOD working so I had to distract myself with some saw time. And boy am I glad I did, because whenever I do, I seem to take leaps forward in my saw sharpening and fettling skills….this week was no different.

I’ve had this war-era Disston #4 back saw sitting in my short till for a few months and I’ve been meaning to retooth it. When I originally bought it back in the spring, it was covered in rust and looking pretty sad with its purely machine shaped handle (you know the ugly ones I’m talking about that Disston insulted us with right before their fall from greatness).

When i first brought her home, I immediately cleaned her up and reshaped the handle. At 16 inches long, she’s a true tenon saw….def hard to find in this vintage.  The teeth however, at 12 points per inch, were peg filed, as is common to find with older saws, and with fleam to boot….not going to fly as a tenon saw at all!

Here she is after a day at my spa…

After cleaning her up, I put her on the shelf with plans of re-toothing her soon, but you know how that goes….summer…fall….and here we are.

So I took her down a couple nights ago, with arms sore from planing white oak, and I decided the time had come for that re-toothing. I was set on 10 points, rip cut (no fleam), and about 7 degrees of negative rake….my favorite recipe for tenon saw teeth.

The first step of course, as she was a 12 point saw, was de-toothing her before I could re-tooth her.

So, over to the grinder we go…and quick work here (a lot faster than filing them all away….aarrrrrggghh!!!!)

I leave just the bottoms of the gullets left and chuck her into the saw vise to take her down to a clean line with a mill file…

You can see I’m skewing the file here just a bit to make a cleaner cut. And the last two strokes I turn the file 90 degrees to the tooth line and draw file it for a really smooth finish.

Next, I mark out the tooth spacing with a fine Sharpie and threaded rod as a guide. You can use lots of little tricks to mark the tooth spacing…I’ve been meaning to try those templates from Lief at Norse Woodsmith…gotta upgrade my process…

To start filing in the teeth, I use a very light touch and take one stroke across the Sharpie mark to simply create a groove for subsequent strokes…no heavy filing here…its quick and easy…

Now that a groove is created at the correct spacing, I can focus on makin’ teeth. I don’t take more than two or three strokes with the file per tooth…you really want to keep your spacing accurate and its best done bit by bit.

A few minutes and a few passes and the teeth are just about shaped…

After the first shaping, I joint the teeth and then perfect the spacing by paying close attention to the gullets and “moving” certain teeth forward of back by accentuating my file stroke to the left or right. This is honestly the trickiest part of filing….it can get real tedious so I take my time.

Here they are all shaped…

Now comes the part where lots of people do different things…some sharpen now, then set, some set them sharpen…and the fight goes on.

I like to first set the teeth, joint them again, and then finish with the sharpening. I think it’s absolutely paramount to joint the teeth after you set them because the setting process changes the presentation of the tooth point to the wood (Mike Wenzloff explains it better than I do). By jointing after setting, you return the tooth point to a true perpendicular to the wood when you saw.

I set with my Stanley 42 on the smallest setting…

Followed by a jointing, the final filing, a light stoning of the set, and voila….she bites wood again!!!!

I chucked some 10/4 white oak into my leg vise and hastily scribed some plumb lines to simulate tenon cheek cuts. She needed just a little more taken off the right (because I file my teeth all from the same side, my saws always steer to the right and need to stone a little more off that side due to the burr) and after that it was like buttah’!!!

The 16 inch saw plate really helps to keep the cuts lined up and with 3 and 5/8 under the back, I can reach serious depth without needing to switch to a panel saw.

Daddy likey!!!!!

With the ache now abated, I can return my focus to the super saw bench in bliss…..aaaahhhhh…all is well in the world once more!

🙂  Matt

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Published in: on December 30, 2010 at 8:24 pm  Comments (13)  

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13 CommentsLeave a comment

  1. Nice work Matt; I’d love to have a saw like this. I think I need to spend some time looking for more saws, my little 12″ carcase saw filed rip doesn’t quite cut it for big tenons.

  2. Thanks Mike. I agree…you will see a world of difference between a carcase saw and a true 16 inch tenon saw….like going from a VW Bug to a Corvette!

    Unfortunately, they’re getting harder to find in the wild in this size.

    I recently came into some great vintage Disston back saw stock and am toying with the idea of making a small batch of 16 inch tenon saws for sale…we’ll see…

    -Matt

  3. Never heard the term ‘peg filed’ could you expand/explain please?

    Thank you,
    Scott

    • Hi Scott

      ‘Peg filed’ means that the face of the tooth and back of the tooth are at the same angle relative to the toothline. This means that the teeth do not have any pronounced forward rake vs. back rake and appear the same whether viewed from the toe or the heel. In essence, the teeth cut on both the forward and return stroke with the same lack of aggresiveness. On a hand saw designed to cut on the push stroke, this is generally a bad thing (especially with a rip saw)….it is really intended for two-man cross cut saws designed for felling and bucking trees so that each mans stroke on oppostie sides of the log does equal work.

      It is very common to find old hand saws with peg filed teeth because they have been resharpened many times without a rake guide. The unguided file stroke quickly settles with the flat of the file parallel with the toothline and the opposing corner of the file in the gullet, thus giving a peg tooth.

      A peg filed hand or back saw will never cut at its best…they are frustrating and annoying to use in my experience.

      Hope that clears things up.
      -Matt

  4. Hi Matt,

    Good work on that young Disston saw. All of those type saws deserve to be reworked, even if in new condition. I often times totally remodel those guys just to get rid of the clunky squared off corners on the handles.

    When retoothing by hand, I do pretty much as you do. Big teeth I grind off on my grinder, then finish the blank edge on my belt sander. For smaller teeth I do it all on the belt sander.

    I like your idea of using a threaded rod for tooth spacing. That’s a good idea. Only problem is, there’s not always a threaded rod with the spacing I want.

    I made a little notching jig using two files spaced apart by about a half inch and held at each end with aluminum bar stock and thumbscrews. The file on the left side is ground smooth. The file on the right files the notch. I clamp a template such as a screw gauge or another saw or what ever has the tooth spacing I want onto the end of the blank saw plate. Using the jig, I file about 5 notches anywhere along the blank edge, then remove the template and then use the 5 notches to continue spacing the rest of the teeth. The smooth file on the left slides in the template while at the same time the file on the right files a notch. This method creates tooth spacing as accurate as the template is and with no slippage and eliminates most of the filing left or right to get the gullets centered. I’m going to rebuild the jig so one of the files is adjustable from left to right so it can be adjusted to match the template teeth directly. Presently, it works off the end of the template and will sometimes not space the teeth the same as the template. This has occurred a couple times to my consternation and surprise. I just recently figured what the problem is. So if you think this is a good idea and decide to make one, be sure to make one of the files adjustable.

    I always set then joint the teeth right after shaping whether rip or crosscut. I then file again. Joint one more time and file one more time. Then lightly joint the sides. I never file without jointing first.

    Who ever thought that peg teeth is a good thing? Thirty degree rake is just stupid.

    Catchalater,
    Marv

    • Thanks Marv!

      I’ve seen pics of your filing jig on Woodnet and remember being quite struck by it…I def would like to make one, as my threaded rod system is certainly wrought with flaws.

      I was just readng Grimshaw this morning and thought about making the little file guide he writes about..its just a piece of steel with a notch that sits in the gullet of a tooth and makes a little fence of sorts for the file to ride against for filing the next tooth.

      Sounds like you and I once again see eye to eye Marv: Peg teeth? Stupid. Boxy Disston totes? Insulting to the hand. Set, joint, file? Ditto.

      🙂
      Matt

  5. You must have the patience of Job.
    yaakov….

  6. Great site. Lots of good advice and photos.

    I’ve only had two saws that needed new teeth cut. One was a nice little dovetail saw with 14 tpi. I was apprehensive to mark them with a Sharpie as my eyes aren’t as young as they used to be and I was worried about the file “skating” off the line.

    My solution was a hacksaw blade. I wend to the hardware store, found a blade with 14 tpi and clamped it to my dovetail saw. Now I had a precise register for the file. Most hacksaw blades have some type of coloring on them when they’re brand new, so I just file until the color files off and I know I’ve reached the right depth.

    Probably not an original idea, but it’s worth noting. It works great, the blade is cheap and once you’re done, you can use it in a hacksaw.

    • Thanks for the comment and support. I know many people like the hacksaw blade method….I’m hesitant to subject file teeth to a hacksaw blade. I can imagine you wear out the file pretty quickly?
      -Matt

  7. Really like your Blog! Maybe you’ve already explained this somewhere but, What is negative rake? Stevie.

    • Hey Stevie
      Thanks for the comment.

      As for negative rake: Imagine a line perpendicular (90 degrees) to the toothline of the saw. Now picture the cutting face of each tooth as parallel with that line (therefore also 90 degrees from the toothline). Any amount that the cutting face of each tooth is angled back from that perpendicular line is considered negative rake. The more a tooth is raked back from perpendicular, the less resistance it offers to the work, and hence the easier the saw strokes in forward thrust. Also, negative raked teeth tend to leave a smoother surface.

      However, the downside is that the more a tooth is negatively raked, the smaller a bite of wood it takes and thusly, the slower it cuts.

      So, deciding on how much rake to file into any given saw becomes a balancing act between ease of thrust, smoothness of finish, and speed of the saw when cutting. I tend to like aggresively raked saws…I do all of my sawing by hand, so I like the work to go quickly. Any roughness in the surface can easily be planed smooth.

      Generally speaking, rip saws have between 0 and 10 degrees of rake, cross cut hand saws have 5 to 25 degrees of rake, and back saws have from 10 to 30 degrees of rake.

      Interestingly enough, Western hand and back saws only have negative rake, so whenever you hear about rake, you can assume its negative rake. However, Japanese hand saws actually have positive rake….the teeth point forward so that they dig in when pulled toward the sawyer.

      On a final note, all of the teeth on a saw do not have to be raked the same. By relaxing the rake of the teeth for the first few inches on a hand saw, you can make it easier to start a kerf, and then file the teeth after those first few inches with less rake to keep the saw cutting aggresively.

      There’s lote more to say about rake….one could teach a whole class on rake!!! 🙂

      Hope this helps…
      -Matt

  8. […] cuts…a 16 inch tenon saw filed 10 points rip. You can read about the re-birth of my new saw here in my last […]

  9. […] Things are really getting exciting now! Cutting tenons this deep and thick in white oak is definitely work, but it is truly a pleasure. I absolutely LOVE my new tenon saw….I couldn’t even imagine sawing these monsters with a 12 inch saw. You can read all about my newest 16 inch spring steel companion here. […]


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