What’s Wrong With the “Standard” Set of Chisels?

Shannon Rogers interviewed me a few weeks ago and in the interview I mentioned my disdain for certain chisel sizes. Specifically, I said that students who come to woodworking classes armed with the standard set of 1/4″, 1/2″, 3/4″ and 1″ have four chisels all of which are the wrong size. OK, that’s a bit of hyperbole. But how much, exactly? Several listeners have asked for more detail about this, including Shannon, and I thought it might be helpful to type my thoughts on the subject here. You probably shouldn’t be surprised to learn I’ve given the subject a lot of thought. Lacking power tools, I rely on chisels heavily.

Many many students are chopping dovetails in woodworking classes. And unfortunately, woodworkers have placed an anachronistic value on what they call “London Pattern” dovetails. More about that some other time. When working a narrow range of thickness of wood, with a narrow range of dovetail angles, the resulting chisel width required is also limited. For 1/2″ stock, and depending on your chisel’s pattern, it’s possible 1/4″ may be slightly too big to get a really narrow pin. Honestly, this isn’t too big a deal. I’ve long advocated sizing your dovetails to your chisel. It may be that the 1/4″ chisel is one of the more useful sizes in your set of four. I have what Benjamin Seaton would call a 1/4″ “bare,” meaning a chisel slightly under 1/4″.  I have found this tool helpful.

For 3/4″ stock, like that used in many or most classes, you really want a 5/16″ chisel.  A 1/4″ chisel is too small and a 1/2″ chisel is much too large. At the very least, a 3/8″ chisel is helpful. In general, when chopping dovetails, I find having a few chisels of around 1/4″ (both oversized and undersized) and a few of around 1/2″ is helpful.

So what are my recommendations for a set of chisels? I think Lie-Nielsen had the right idea in offering a set of four as 1/4″, 3/8″, 1/2″, and 5/8″. That make a lot of sense to me. But I think it would be great to have 3/16″, 5/16″, 7/16″ and 9/16″.  In many ways, I think I’d like those more. Again, if you are following me, it has to do with what you actually need in real-world use. Not surprisingly, we encounter a fairly narrow range of joint sizes based on our stock size.

In addition to that is the concept I call “The Cooperative Workshop.”  In this concept, I’ve discussed the need for tools to help each other, chisels matching plows, mortisers, dado planes etc., and for plow irons and mortisers to be one-third of standard stock thicknesses. For this reason, I struggle to recommend metric chisels like the oft-recommended Hirsch firmers.

Hirsch chisels are available in a range of (metric) sizes. I’ve seen (and purchased) a 2mm, (completely worthless tool), 6mm (a reasonable 1/4″ bare), 10mm (too big to be a usable 3/8″ but too small to be a usable 1/2″ bare), 12mm (a reasonable 1/2″ bare) 16mm (very close to 5/8″ and helpful. Let’s call it 5/8″ full), 20mm (too big for 3/4″ dados, wider than most stock) and 26mm (larger than 1″ and can be useful but otherwise holds no real advantage over a 1″ tool). Metric chisels can be a good source of off-sizes (full and bare is the 18th-century lingo for slightly more than and slightly less than), but I certainly could never live with them as a “standard” set of chisel. Most egregious are the sellers who list metric tools only in approximate inch “equivalents.” I guess this isn’t so bad when selling carving tools. Otherwise, list the metric sizes. Americans really can divide by 25.4.

My much-maligned set of four (1/4″, 1/2″,3/4″, and 1″) also presupposes that the chisels in that set are in some way related. They often share design features including handle shapes and sizes but especially blade shapes (patterns) which I feel are inappropriate. My “Chisel Physics” (my term for my understanding of how chisels ACTUALLY work as opposed to how we THINK they work) suggests that in use, the 1/4″ chisel is nothing whatsoever like the 3/4″, let alone the 1″ tool. In use, the pressure you can apply to wood is very different depending on the width of chisel you hold. This causes the wood to behave differently and results in a different user experience.

I advocate that chisels be sharpened, certainly in accordance with their function, but also with respect to their size. Small chisels, 1/4″ and under, are essentially punches. A sharpened nail will likely hold its edge as well as any given 1/8″ chisel. And virtually any bevel angle will work (including 90°  bevel angles) for many jobs.  I find 1/2″ chisels to be particularly sensitive to bevel angles. These dovetail workhorses see a great deal of use and are the toughest to sharpen correctly. Large chisels, 3/4″ and above, offer so little pressure for most jobs that they can be ground back, with fairly low bevel angles.

Now just to head off my Australian friends at the pass, my sense of chisel physics assumes the use of Eastern U.S. cabinet woods: cherry, walnut, tulip poplar, cedar, and – though it’s not local – mahogany. Interestingly, the toughest wood on my chisels is pine. If you’ve followed my logic so far, you instantly know why. The hard/soft rings of pine, especially quartered pine (the use of which I advocate), poses a unique problem for an edge tool. Pressure is concentrated discreetly, instead of spread evenly across the cutting edge. And I believe that the hard parts in pine are pretty darned hard compared to other woods (like those previously mentioned), but I don’t know that for sure.

So the moral of the story is, when it comes to chisels, size matters.

Adam

11 thoughts on “What’s Wrong With the “Standard” Set of Chisels?

  1. Texchappy

    As a green new woodworker (as I am), how would you go about finding chisels in the sizes you mentioned? Is vintage the only way to go? If so, is there things to look for?

  2. David Keller

    Adam – One more aspect of “modern” vs. traditional chisel design might be worth addressing – thickness. I’ve a lot of antiques, including some that were definitely hand-forged. But even the drop-forged ones from the early and mid 19th century are far thinner than today’s chisels.

    I offer as examples Lie-Nielsen’s socket chisels and Blue Spruce ToolWorkks bench chisels. Tom and David’s tools are wonderfully made, inexpensive for what they are, and have mettalurgy to die for. Yet, both (and all others by other makers, as far as I’m aware) are too thick. Typically, the metal of the chisel is about 1/4″ in depth, and that’s about 1/8″ too much. The extra steel may well make the chisels suitable for wailing on them with a railroad spike mallet, but it makes them ungainly in use in the cabinet shop. Even 3/32nds thick would be welcome.

    If you have any pull with a tool maker, encouraging them to produce something thin would be very helpful.

  3. David Keller

    “Being from Australia, the chisels are used counter from how I would normally apply one. Holding the chisel handle in one hand, firmly against the wood to be cut, I would hit the cutting edge with my mallet. Time after time, all I achieved was to dent the wood, chew up the mallet and dull the chisel edge.”

    Ha! I wonder how many got that joke…..

  4. xMike

    Well, rats!
    I have not one but two sets of chisels in the (now) vile size format. I use one set as a firmer set and one as a paring set, thus solving part of the “won’t hold an edge” problem.
    Thought I was soooo clever. But now…..
    A 1/8″ chisel? Hummmmm. Hey, here’s a big nail!
    Gotta rethink this chisel thing – one thing’s for sure – I won’t ever lust after a “set” of chisels from Lee-Valley again. Sorry Canada.

  5. Adam CherubiniAdam Cherubini Post author

    Period woodworkers typically had firmer chisels in 1/8″ increments from 1/8″ to 1″ and period accounts indicate they hade large numbers of chisels. Most of us have neither.

    Many of my friends who have many chisels often have many of the same sort of chisel, which is probably not typical of period craftsmen.

    I don’t want to leave anyone with the impression that I think it’s importnat to have a chisel that measures .250000″. The point of the blog is that you may well need a 3/8″ chisel and you may even need something inbetween 1/4″ and 3/8″, plus something smaller than 1/4″.

    1/4″, 1/2″, 3/4″, and 1″ aren’t really going to cut it. In my opinion, depending on the sort of work you do, it may not even be a good place to start.

  6. Jonas Jensen

    Maybe a standard set of chisels today is developed to suit DIY project around the house, more than building period furniture.
    That could explain why so many students come equipped with a set which is not too useful.

    I have to second Gary, the I too don’t measure my chisels before using them, but I think that I mostly use my 10 mm, 12 mm, 25 mm, 30 mm and 37 mm, (3/8″, 1/2″, 1″, 11/4″, 11/2″).
    They seem to do for my uses. I try to make some shaker style furniture, but only based on the looks, I follow my own design, so I am not sure if that can be called period furniture.
    Brgds
    Jonas

  7. Gary Roberts

    In all seriousness, I doubt that 19th C chisel makers and woodworkers felt the need for micrometer precision. To set a mortise gauge, you adjust the gauge points to the chisel you are using and then mark the stock. There is no need for a chisel of a precise dimension.

    To be honest, I really have no idea what sizes the various chisels I use are. When selecting one, I eyeball what I need.

    The manufacturer had to designate sizes for the market, else how could people know what to buy or the manufacturer know what to make? It’s like dado planes. Every now and then you come across an oddball size. Planemakers advertised special orders so I am sure at times someone needed a particular plane for a large project. Or that someone was simply very obsessive about measurements and demanded precision.

  8. Gary Roberts

    Adam

    I agree with you on the subject of Australian woods and chisels. I purchased a nice set of Australian made chisels and I have to say, they were impossible to use. No matter how I sharpened them, how hard or soft I malletted them, the cutting edge broke and the wood was unharmed save for some denting. I have a suspicion the problem resided in my technique.

    Being from Australia, the chisels are used counter from how I would normally apply one. Holding the chisel handle in one hand, firmly against the wood to be cut, I would hit the cutting edge with my mallet. Time after time, all I achieved was to dent the wood, chew up the mallet and dull the chisel edge. Clearly, Australian chisels are made to be used on wood native to Australia and not from New England.

  9. millcrek

    Adam, Over the years I have collected and used a lot of old chisels. I especially like old Buck and D.R. Barton. I have found that most of the old chisels are 1/8, 1/4, 1/2 etc. in name only, they very both + and – in width, however the old catalogs list them as inch sizes. Often on the auction site you will see old chisels listed in 32nds. Do you believe these variations in width are user modifications, manufactured in on purpose or just accidental.

    1. Adam CherubiniAdam Cherubini Post author

      I too have seen variations in chisel width. I think there are a number of factors at play. One is hand forging. My guess is few of the tools we encounter as antiques are truly hand forged. Most are drop forged.

      Grinding was done by hand for a very long time in Sheffield. Grinders (people not machines) were capable of tremendous precision, but they tended to be precise about things other than width. The draft angle on the sides of a mortise chisel are often very precisely ground. Width of mortisers is often quite good as well.

      Many chisels actually tapered in width, narrower towards the bolster. That can introduce small (minute) variations in width as the tool is shortened thru use. 1/32″ is quite a large difference from nominal if you think about it. I’d have to audit my chisels to see how much they vary. I would expect at least .010 off nominal (which is significant for many operations you or I would perform).

      Adam

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