Chris Schwarz's Blog

Splitting the Line

Whenever I demonstrate handsawing, someone usually asks this question: “Should you saw right on the knife line or next to your line?”

I answer: “It depends. Usually I split the knife line.”

They usually respond with something like: “Yeah, and I’m a Chinese jet pilot.”

So I show them. And now that we have a cool new macro lens at the magazine, I can show you, too. Above is the shoulder of a dovetail joint I cut this morning. The knife line at the edges was made with a cutting gauge.

I am not showing off. This is easy to do with a sharp saw and a little practice. Not years. Not months. It takes just a couple days, really.

Here’s my advice: Practice. Don’t practice on a real project. (There’s a reason that surgeons practice on cadavers.) Practice on scrap. After a few hours of work you’ll find it easy to follow a line. After a few more you’ll cleave a knife line in twain.

Other sawing advice can be found in my treatise on sawing in the Spring 2008 issue.

– Christopher Schwarz

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17 thoughts on “Splitting the Line

  1. Nathan

    This is a great picture for me to see, as I have wondered if that amount of wood sticking out past the line is a hinderance, i’ve always pared it off before but now I shall see if I get good results without the paring.
    Nathan

  2. Christopher Schwarz

    John,

    It’s a line from one of my favorite movies, "Army of Darkness." Not racist. Promise.

    Chris

  3. John

    Chinese jet pilot – Chris you know better – I think you need to be more generic IE jet pilot or neurosurgeon.

  4. Mike Siemsen

    I think you can learn everything need to know about woodworking in 15 minutes,
    The rest is practice.
    Nice sawing!
    Mike

    "I know you’ve heard it a thousand times before. But it’s true — hard work pays off. If you want to be good, you have to practice, practice, practice. If you don’t love something, then don’t do it."
    Ray Bradbury

    "In theory there’s no difference between theory and practice. In practice there is."
    Yogi Berra

    "Every day you miss Practicing, it will take you one day longer to get good."
    Ben Hogan

    It’s not practice that makes perfect….but perfect practice that makes perfect.
    Cal Ripken Sr.

    It’s all very well in practice, but it will never work in theory.
    French management saying

  5. Samson

    Dick, I’m not sure I understand your question, but if you are asking about the "line" being referred to in the phrase sawing to the line or plitting the line, we mean literally the line created by the blade of a wheel gauge or a marking knife when marking out the joint to be cut. Some may use pencil lines instead, but the meaning is the same: the mark that dilineates waste from work.

  6. Richard Petti

    I’m new to this is there a place that I can look and start to understand what you are all talking about the line? Thanks Dick.

  7. Christopher Schwarz

    Ken,

    One of the benefits of knowing your saw is knowing its set. I position the set of this saw to split the line. I know this sounds all impossible, but it is not (with a little practice).

    Chris

  8. Ken N

    Wait a minute. If you are splitting the knife line, wouldn’t the set of the saw teeth obliterate the knife line? Aren’t you sawing with the teeth of the saw touching the line rather than splitting the line? Just a matter of semantics; your skill in sawing is evident.

  9. Samson

    "I have found that the more you mess with a joint the more likely you will ruin it. The more steps you add to an operation, the more chance that one of them will be faulty."

    Can’t argue with that, as it’s statistically unassailable as a general matter. What it misses, I think, is that it is the relative risk of something going wrong with each particular operation that matters, and not so much the pure number of operations it takes to get to the result. Walking on a diagonal across an intersection comes to mind versus crossing both streets in the cross walk.

    In my experience, learning to pare to a line accurately 100% of the time is a more easily attained skill than sawing to the line perfectly 100% of the time.

    "So I’ll fix the joint if it’s open (as noted in the entry). I like tight joints, too."

    No doubt, but it’s one thing to pare EXTRA from the waste side, and it’s another to ADD material back if you stray into the good side. Sometimes it’s recoverable – say if the length of the stick between tenon shoulders is not crucial and you can just move the shoulder, but other times it means going to the rack for a new piece of wood. And even if it is recoverable, I dare say the fix will take you far longer than any slight paring would have taken on the front side.

    By the way, I worry that it might be hard to tell in written form, but I don’t say any of this aggressively or trying to be smart. If we were standing in your shop, woodworker to woodworker, I’d be saying the same stuff and hopefully in a tone that let you know it was just a good nature disagreement on methods (oh so common among us woodworkers, eh?!).

    Have a good weekend!

  10. Christopher Schwarz

    Wilbur,

    Great idea. You are right that we try to make our surfaces look like they came from an electric router. Not all surfaces need to look like that. You’d be surprised, however, how good some of them look with a little practice.

    Samson,

    Good point. The reason I work from the saw isn’t to be speedy, it’s too be accurate. I have found that the more you mess with a joint the more likely you will ruin it. The more steps you add to an operation, the more chance that one of them will be faulty.

    So I’ll fix the joint if it’s open (as noted in the entry). I like tight joints, too.

    And Mike,

    I do warm up. I do the least critical cuts first — such as the slopes of the tails. By the time I get to the shoulders, I’m on line.

    Chris

  11. Wilbur Pan

    Now that you have that macro lens, I have an idea for an article. It might be worthwhile to do some hand tool operations and show what kind of surface is left by the hand tools that still make for good joinery. I know that for me, a big part of the learning curve that I am still getting over is that I see what a tenon made on a tablesaw looks like, and I try to duplicate it with handsaws and chisels, and I’m just learning that such a degree of precision isn’t completely necessary.

  12. Samson

    One other question: I understand that time is money, so colonial cabinet makers and such would certainly want to work from the saw as much as possible (and it shows in many of the antiques I’ve seen up close where gappy dts are a common sight), but if you are a hobbiest for whom not wasting a rare or expensive board or having flawless visible joinery is more important than a few minutes one way or the other, is there an advantage or reason to aspire to "work from the saw as much as possible"?

  13. Mike N

    You are a true master.

    I can never summon the courage to get that close to my line. I suspect this is because i suck at sawing.

    Do you do any sort of warm-up on scrap before you get going on real stock or is sawing like riding a bike for you? Gary Rogowski has mentioned how he does his "5 minute dovetails" at the start of each shop session.

    Mike

  14. Samson

    Did you cut the long tenon shoulders on the front rail in the post below in the same manner?

    Do you EVER miss by a hair at some portion of the cut? because if I couldn’t do it 100% of the time, I’d rather leave a couple sheets of paper’s thickness as insurance. Paring that amount of waste to a knifed line is quick and sure work. Such points may not matter much for dovetails, but do much more so with tenons.

  15. Dean Jansa

    Nice example of "witness protection." This same idea is useful when using a plane. A panel gauge will leave these witness marks, handy as you get feather edges when you are close to the marks. Visual yield signs.

    -Dean

  16. Christopher Schwarz

    Depends.

    If the joint won’t close, I’ll pare it back. Usually that amount of waste doesn’t cause any problem. It compresses during the interlock.

    I try to work straight from the saw as much as possible. But I am not afraid (or ashamed) to chisel.

    Chris

  17. Chris F

    I’m curious…on the pictured board would you pare the sawn area to bring it level with the knife line? Or is it good enough as it stands?

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