Rake and Rip saws…

The first time I got my hands on a proper rip saw was, unfortunately,  a bitter-sweet experience.

It was sweet because it was the first moment of the rest of my woodworking life….like a door had been opened to a place that was fun, fulfilling, and free from the threat of lung cancer and systematic dismemberment. But it was bitter because I was frustrated with the performance of the saw….and just so you know, the saw wasn’t from Home Depot or Ace Hardware. The saw was a vintage Disston D-8 with a thumbhole from the classic 1896 to 1917 era…we’re talking about the greatest rip saw ever made by human hands. And it was professionally sharpened by a well-respected saw guru. So what was the problem?

Well, the saw was gorgeous, perfectly tuned, sharp as English wit, but to my inexperienced hands, every time I stroked the saw through wood, it was not a pleasant experience. The teeth felt like they were sticking in the wood…and like I had to push really hard to get them to cut. I could feel the moment each tooth sheared a chunk of fibers from the board, and that feeling reverberated from the teeth, to the saw plate, to the tote, to my palm, and up my arm to my shoulder. It was jittery and rough and un-nerving. And I was pissed.

What the hell?!?!? This was not the zen like experience I had read about in the pages of books and magazines…this was a hands on demonstration of why people started the asinine folk art craze of painting on hand saws instead of using them!!!

Well, like most things in life, it turns out knowledge really is power. And in this case, the knowledge I didn’t have about rip saws was disempowering me to use them. What I quickly learned was that hand saws, much UNLIKE powered saws, require an intimate knowledge of their form and function to use properly.

Any toothless caveman can go to Home Despot, buy a $99 table saw, plug it in, and be ripping white oak all day long like he was Norm Abrams. But to do so with a hand rip saw requires knowledge of the physiology of wood, body mechanics, and saw tooth geometry.

So which one was I missing?…..the one about saw tooth geometry, and in this case, that was the most critical absence. You see, what I did not yet understand about rip saw teeth was the fundamentals of tooth rake. And the rake was what was making this saw cut like a jack hammer.

Rake, or “pitch” as it also is traditionally called, (not to be confused with the common, modern designation of pitch meaning tooth spacing) is the measure in degrees that the face of each cutting tooth is rotated back from 90 degrees relative to the tooth line. The illustration below (from Disston and Sons “Lumberman Handbook”, 1907) demonstrates two different rakes….

In the first image is shown a saw with 0 (zero) degrees of rake. The face of each tooth is 90 degrees to the tooth line, and in effect not raked forward (like Japanese saws) and not raked backward.

In the second image is shown a saw with 12 (twelve) degrees of rake, meaning that the face of each tooth is rotated back 12 degrees from vertical (90 degrees from the tooth line).

So, what’s this have to do with how a saw cuts? Lots. And lots. And….well, you get the idea. Which is this: the greater the teeth are raked back from vertical, the less resistance the teeth encounter as they cut the wood. So teeth with zero rake–meaning the cutting faces of each tooth are 90 degrees from the tooth line–will cut more aggressively and meet with more resistance than teeth that are raked 5 degrees back from vertical (relative to the toothline). Make sense? Good.

I should also point out that the more teeth are raked back, the less aggressively they cut. So before you go and file 25 degrees of rake into all your rip saws, you should know that by doing so, you’re effectively turning them into giant bread knives. Not good for wood!

So, can you guess how much rake was on the teeth on that fortuitous first D-8?

Zero degrees. And if you’re paying attention at home, you now know that means that the face of each cutting tooth was 90 degrees from the tooth line…just like in the first illustration above.

And that’s why my first nice rip saw–though perfectly tuned and filed with a precision that would make even ole Henry Disston proud–made me want to call the guy I sold my table saw to and beg him to sell it back to me!!!!! But I didn’t give up. In stead, I started filing my own saws and here’s what I figured out…

The reality that I discovered about rip saws, is that there’s a sweet spot relating to the rake of the teeth. And by that, I mean you have to strike a balance between relaxing the rake to cut smoothly, and still have it be aggressive enough to actually do some work. For me, that sweet spot is about 5 degrees of negative rake for most saws with 6 or 7 points per inch, and about 5 to 10 degrees for more course toothed saws. You can play with the range of rakes, but anything much past 10 and you start to lose a lot of performance from your saw.

The other important point to mention here is that I work mostly with hard woods, and hard woods are the ones that respond nicely to a little relaxing in the rake department. If all I was ripping was white pine and even a little poplar, I’d probably be okay with zero rake rip saws. But the truth is, I work a lot with white oak, maple, cherry, locust, walnut, etc….some very hard woods. And believe me….a little relaxed rake goes a looooooonnngggg way. Those 5 little degrees that each tooth is swept back turn them into sweet little stanley #80 scraper blades….very nice! As opposed to zero rake teeth, which act more like a dull scrub plane iron on end grain. Ch-ch-ch-ch-chattering teeth anyone???

And just in case you’re curious, here’s some pics to illustrate…

First, is a 5 and 1/2 point saw with zero rake…given the tooth spacing and rake of this saw, I can comfortable rip pine, fir and poplar…

And here’s one of my favorite rip saws….a Wenzloff 5 point with 10 degrees of negative rake….and she is a sweet ripper! This is the saw that I used to make TheBigRip. Mike Wenzloff, smart guy that he is, recommended this rake and damn if he wasn’t right as rain. 🙂 I use this saw to do all of my heavy ripping…anything 8/4 and up in white oak and the like….

So, that’s the skinny on rip saws and rake. I encourage you to pick up a few and check out the rake, start filing and never stop trying new things.

I have to remind myself every day that this slippery slope of hand tool work is littered with unsolved mysteries and long-lost skills begging to be rediscovered.

Here’s to the next revelation!

-Matt 🙂

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Published in: on March 10, 2011 at 9:05 pm  Comments (17)  

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17 CommentsLeave a comment

  1. Very enlightening! I’m still waiting for my eBay win to get to me (they’re in customs lockd

    • Darn iPhone. I was saying … lockdown).
      When they arrive, I’ll put that info to good use 🙂

      • Hi Mike
        Glad you enjoyed the post…thanks for the support!
        -Matt

  2. Hi Matt,

    let me addanother point of view. When a sawyer gets a well sharpened saw for the first time he isn’t used to it. He is used to these semy dull small toothed junk he got from BORG. To “saw” with this junk he had to press the teeth in the wood. I he gives the same amount of downward pressure to a well sharpenend D8 it is to much. The saw gets too aggressive. I saw your arms, I think, that could have hapened to you. 🙂

    The D8 has a quite high hang of the blade. Adam Cherubini tells, that this was invented to be able to saw with a dull saw because it the sawyers couldn’t sharpen their saws on the jobe site. So if it is sharpened well a sawyer will have to saw with less downward pressure.

    But for this high hang a more relaxed hang angle is prbably the best.

    Cheers
    PEdder

    • Pedder
      A very true insight…thank you for your thoughts. I agree that hang has a lot to do with how the saw cuts, and I have read Adam’s perspective’s on this and have emailed with him regarding the change in the hang of saws startd by the introduction of the D-8.

      Interestingly enough, that’s why I now only use saws with a traditional hang….I don’t like D-8s or saws with a let in handle. I like the #7s, 9s and 12s and older british saws with a more perpendicular hang to the tooth line.

      -Matt

  3. Hey Matt,

    I’m sure you’re already seen this, but perhaps others have not. Your experience matches a section of the Saw Filing Primer over on vintage saws. Apparently Disston was using 8 degrees of rake as a standard, due to it being easier to start and easier to use for the inexperienced.

    I’d also echo what PEdder said about pressure. I just finished ripping a 8′ section of 12/4 poplar with a 5 1/2 PPI D8, and I found that at the start I was using WAY too much pressure. Using a lighter touch let me use the full saw plate and go faster with less effort. I also moved the slab up onto a 34″ bench and used the overhand grip Schwarz demonstrates for about half the plank. It really is remarkably less tiring, and I found it easier to keep the saw plumb.

    • Hi Ben
      Thanks for the comment….and I agree…proper technique is a big part of sawing well.

      -Matt

  4. Very informative post, Matt; thanks.

    The best part is that I can now see the need for at least 6 rip saws to maximize efficiency in soft and hard woods ranging from, say, 1/2″ to 4″ in thickness. Of course that really means at least 12 – 1 each ready to go and 6 or more at various points in the sharpening queue. I really don’t have a saw problem after all.

    • Excellent! Neither do I! 😉
      Matt

  5. Great post Matt. One day you should gather up your blogs and turn it into a book.

    yaakov….

    • thanks Yaakov….but first, I think I have to finish your saw! ;)-Matt

  6. Of course! I consider myself a professional level sharpener when it comes to knives, plane irons, axes, etc, but I’m still pretty new to saw sharpening. I picked up a cheap Disston panel saw last week and sharpened it up rip, and I was a bit underwhelmed. I had forgot to take into account the rake, and because I eyeball everything, it never occurred to me to measure it. I just did measure, and it’s coming in at about 17 degrees, which based on using it for the last week I think is way too relaxed for a 10 point saw. It cuts well enough, but way too slowly. I’ll have to do something about that.

    Thanks for bringing this to my attention and sharing your experiences!

  7. I always enjoyed the making and fixing of things more than the ownership or use of them.
    In time sharp saws lose their appeal. The real joy is in finding another one to sharpen.

  8. great explanation Matt, thanks for bringing it out to light

  9. Matt,

    If I’m following you correctly your Wenzlhoff has 10 degree rake toward the toe of the saw. But in your close up with the square it looks like 10 degrees toward the heel. Am I getting your positive and negative rake directions backwards?

    • Yup…you’ve got it backwards…western saws have negative rake because they are raked back towards the heel of the saw. So, my Wenzloff has the teeth raked 10 degrees from vertical toward the heel.
      -Matt

  10. Matt,
    I enjoyed your post. Your story reminds me of a recent experience of using a staircase saw to cuts sliding dovetails in the seats of two board chairs. I was making slots for battens to hold the chair legs. I tried using a brand new German made saw and it had 0 degree rake and couldn’t cut despite my best efforts.
    Once I took a file to it and gave it some negative
    rake it helped tremendously. Like you I think the world of Mike Wenzloff and his saws as well as his helpfulness. Mike has been helpful to me in numerous instances and recently in helping me make an 18th Century frame saw that is 3 foot long and used for making veneer.
    Blessings on your endeavors.
    Jim


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