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More on your knife.

Left handed knife

I hear often of left and right handed knives and how they aid vertical cutting in woodworking. In general that’s not altogether true. It’s a rare phenomenon that one person can use both hands with equal dexterity  and exactness; that is, most of, left or right handed, cannot work using both hands capably with the same measure of accuracy, power and deliberation with our less dominant hand. It is actually far less problematic to adjust the work to task than use a knife or tool with only 10-20% efficiency. Paying $40 or £30 for a specialist knife such as a spear or diamond point knife means you must justify the price—trying to persuade someone that they wasted their money therefore become impossible. That said, there are times when you must use your less dominant hand, but that is quite rare. having said all of that, the benefit of a single knife blade capable of dealing with left and right hand cuts or working from the right and left side of a straight edge with the roll of a thumb has great appeal to the intellect, regardless of whether that works or not.

Inevitably the knife points above must be sharpened like these to gain a viable cutting edge and that is not much of an issue.

Using a sharp knife with my left (non dominant in my case) hand is like stirring my tea with my left hand. I can do it, but it feels awkward—now stirring is one thing. Now, as an experiment, try using a pair of scissors with the “other” hand or, even more difficult, try writing your name that way. Because someone invents something, we don’t have to fit our bodies to make it work.

It’s much easier, quicker, more accurate, controllable and powerful to train the dominant hand to task than the other. That being so, the conventional knife edge with twin bevels on opposite sides forming the same cutting edge enables both left and right-sided cuts with the same hand by simply compensating for the bevel of the knife. Most knives are 10-degrees, so it’s simply a question of tilting slightly as you cut and training your body to what it is naturally disposed to do. (no pun intended).

In woodworking we rarely use the knife for much more than severing the surface grain fibres to a depth of say 2mm or 1/16”. That being so, even if we are out of perpendicular by a further 10-degrees, it is unlikely that it will make any consequential difference or damage.

Almost all of our cuts are made against a straightedge, so as long as we angle the bevel into the straightedge, our surface cut line will show perfectly straight—usually we follow on with subsequent cuts with the chisel or saw—rarely with more knife cuts.

So what’s wrong with diamond or spear-point knives?

Spear-point knives make logical sense, yet in practice I find them awkward to use with left and right hand, which supposedly is the purpose of the design. If they were designed to be used by the two categories of people—left-and right-handed people, the design is perfect, but that is not the case. They are supposed to remove the need for two knives when in reality we never needed two knives to begin with and all of the craftsmen I ever knew never had but one knife. Also, the great assumption n all of this is the assumption that it’s purely a question of training your less dominant hand to use the device, but that’s not true at all, primarily because it is not necessary and therefore it becomes more impractical than practical. I have not met anyone yet who I saw use this knife with anywhere near equal alacrity and switched readily from left to right hand. I have however seen them switch their work to accommodate the dominant hand and arm constantly, which is what we do all day long every day without thinking. Inevitably again, spear point knives I have seen and used owned by other people almost always had the point missing or were corrected by rounding the point to a continuous edge as shown here.

Neat concept, highly impractical for something so intended to be, well, practical.

13 Comments

  1. Dear Paul,
    I own several marking knives and as I start layouts I put all my knives on the bench to see which I would reach for instinctively. Interestingly I always reach for a chip carving knife, just as shown on you drawing which has a bevels on both sides, I never reach for the fancy spear point ones that are called marking knives by the manufacturer. If I force myself to use them they feel uncomfortable and awkward.
    So I completely agree with what you said about knives.
    Norbert

  2. Paul,

    I use a spear-point knife in my dominant (right) hand. I always hold it with the bevel away from the registration surface (straight edge, dovetail pin, etc.). If the registration surface is to the right of the knife, I hold the knife with the bevels to the left. If the registration surface is to the left, I roll the knife 180 degrees but sill use the same hand.

    Chris

    1. I think that as I said in my post, that’s what most people do, but they wont for some reason say so. I just watch to see what people do. Not at all to catch them out, just to see if they do it and if not why not. Answering the ‘why not’ tells me they feel uncomfortable with it. Nuff said.

  3. With the greatest respect, Mr. Sellers, I think you have fallen into a linguistic trap here. I don’t think that ‘left handed’ and ‘right handed’, in the context of the spear point knife have anything to do with the hand one uses. Consider this. Assuming you’re right-handed, though it makes no difference, and you are marking out a dovetail, using the pins or tails you’ve already cut as a guide to marking the tails or pins on the second piece. If your first mark follows the left face of your existing cut piece, you’ll place the flat side of your spear-point against the vertical wall of the pin or tail, so that the cutting edge automatically aligns itself as accurately as possible with the line defined by that vertical wall. When you mark from the right hand side of the pin or tail, you simply rotate the spear point through 180 degrees, keeping it in the same hand, and, again, you have a perfect alignment.

    I do agree that that a rounded point is far more functional than an acute point.

  4. Paul,

    I have tried several different knives and find that I prefer the spear point because I like to use the flat back to register against my straight edge. I do not switch hands to use it left or right I simply roll the knife to register the flat side left or right while still using my dominate hand.

    jdm925

  5. I’m obviously late to the party here, but this is the first time Mr. Sellers has a position I disagree with. I didn’t buy a spear point knife, I made one, actually severa, from a broken chair leg and broken pruning saw (bow saw) blade. Before the spear, I made some lefties and righties and double bevels. I saw the spear design and immediately saw the “practicality”. Indeed it IS a joy to be able to mark on either side of a straight edge with a “roll of the thumb”, or mark the opposite direction when the grain is unfavorable without repositioning or even lifting the knife. I knew the first time I used it that my others would remain in the drawer. It just felt right(no puns here), instantly. It simply works better for me. I don’t have to compensate for anything. You are a master craftsman and know what works for you. But I equate using a double bevel knife(for me) to firing a rifle without sights. Your experience and skill let you use “Kentucky windage” and effectively hit the mark every time. Like many things, I think there is more than one right answer. Now you have slipped to 10,423 great ideas to 10,423 :1. HA! Thanks for what you do. I really enjoy watching you work.

    1. Obviously you have the certainty of dexterity in both hands. That might lead everyone to feel they should have too when in reality it is in fact most unlikely. Spear point knives still have inherent problems you can indeed learn to live with and a few people will master left and right hand use to some measure. I have not met but on or two out of the thousands trained who could work with any degree of accuracy using their non-dom hand. Therefore I don’t recommend spear points.

      1. The parent didn’t say anything about using both hands. The point is that you can register the flat side of the knife against your square regardless of whether you need to cut on the left or right side of your square. No need to switch hands, just flip the knife over, and now the flat side is on the other side of the knife.

        Is it a big deal? No, not really. If you have a double-bevel, you’ll get used to tilting your blade, and if you have a single-bevel, you can usually just flip your square around. But if you think the spear point has something to do with being ambidextrous, you’re completely missing the point of this knife design.

  6. Maybe a different point of view…
    I find it awkward to work perpendicular with my knife.
    My arm, hand, knife-coordination is more convenient/natural compensating the 10° bevel.
    I would compare this with Paul’s sharpening method.
    Dropping your hand while pushing forward(convex bevel) is more natural than keeping the bevel flat(like a sharpening jig).

    Working with my body, not against it, gives me more accurate results.

    Paul talks about his experience(really not little), what works for him and what works for the students in his classes.
    This is what he recommends.

    There are always different approaches to a task, and if you find a method/tool that suits you better, and if it gives the results you strive for, take it.
    I think Paul would be the last to hold you back.

    Just my two cents.
    Jens

  7. I bought a spear point some time ago and if I ever find myself back in the stone age hunting game with a spear, well, perhaps it’ll come in handy. The most I use it for in the shop is occasionally starting a screw hole. That’s about it.

  8. I must say that you have made me reassess the value of my R. Murphy adjustable bench knife. 😀

    I did have a Veritas striking knife, and here is my impression – it should not have been bought! The spear point broke off immediately. I saw the flaws that Mr. Sellers speaks of first hand and fully agree.

    However I note that one British tool manufacturer did make a combination scratch awl/spear point. It had a much lower apex to the blade & was double beveled. Mr. Sellers, what is your opinion on those?

  9. “Spear-point knives make logical sense, yet in practice I find them awkward to use with left and right hand, which supposedly is the purpose of the design.”

    I’m not sure this is the case. As Harry stated above, the knife is used in the dominant hand, same as your double-bevel knife. The purpose of the double edge, single-bevel design is to allow the flat side to be set against the left or right side of a square or rule, or against a wood surface (as when marking pins from tails or vice-versa). Held in the dominant hand, it is simply flipped over to register the flat side against the reference surface. It’s also worth noting that these might not be “poor knives based on engineers who mean well but don’t work wood,” as you stated in another post … I first began to see them from Japanese suppliers in the 1970’s when the Japanese tool craze began, and they are most probably based on the kiridashi marking knife, which has been used by Japanese carpenters for quite a few hundred years.

    1. No matter, they work no better than any other knife type and people often justify the expense and awkwardness, the rounded pointless points and so on simply because they bought and own them. In my view they offer no advantage. I think people should just buy them or any knife simply on the basis of their making an educated stab at it. What I don’t like is that people say they work better when in my view they really do not!

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