Re: Fixing a Dovetail Saw
Don McConnell
>Adam Cherubini wrote:
"Strong statements start good discussions and mine has worked as intended!"
Unfortunately, I don't find "the ends justify the means" line of argument to be very compelling. Very often, it amounts to justifying pretty much any kind of behavior/statement - in this case, maligning generations of anglo/american cabinetmakers. Unless, of course, you are prepared to argue that none of them "know how to use a handsaw."
"... My experience has been that old saws with absolutely zero set produce kerfs wider than their blades' thickness (try it yourself everyone). I think this is caused by the natural waviness of hammer straightened saw plates (blades). We must be very careful about comparing these old blades with modern LN or Adria blades which to my eye are excessively straight."
I have tried it, and my experience tells me that the kerf is slightly wider than the gauge of the blade, even on the new saws. If the older saws had any "advantage" in this matter, I believe it more due to the fact that they were often forged and/or ground to a slight taper (i.e. were sligthly thinner at the back than at the edge with the teeth).
"... It could be that the old timers (be they British or otherwise) never truly removed 100% of their set."
Already acknowledged as "residual set."
"... Also, a saw filed but not stoned would pull to one side if its teeth were not filed from alternate sides (or both). It could be the tooth's burr was sufficient set. Keep in mind LN sets 3 mil per side, so even set saws aren't set a lot. So maybe its easy for them to recommend removing set, but I'm not sure we should apply this advice to modern saws."
I would not recommend filing from one side only, except, possibly, for initial defining of teeth when retoothing a saw. Even at that, I *very* lightly stone the sides of the teeth after sharpening. If the "tops," or cutting edges of the teeth are uneven side-to-side, that will also result in a saw which tends to pull to one side. But this isn't just an issue with minimal/zero-set saws. I don't know why you would want to use a saw which didn't tend to cut straight, regardless of the set.
As I said, I have applied this advice to "modern" saws and have been quite satisfied with the results.
"Producing pins and tails which fit straight from the saw has nothing to do with set. As my friend Dean says, you could cut DT's with a chain saw and have them fit. The trick is only sawing to a line- nothing more.
...
"Removing all set to stop you from turning a good start into a terribly bad cut is really quite silly when you think about it. In the same way it guides the good cut, it prevents you from fixing the bad."
As Bugbear has already pointed out, if you are in the position of needing to "fix a bad cut" after it is well underway, then you've already left material where you don't want it, or have removed material which will leave a gap. So, yes, the idea of producing dovetails straight from the saw does have to do with set. Not sure how a chainsaw fits into this discussion, but if your friend can produce passable cabinet grade/scale drawer dovetails with his, then I'll have to take that line of argument a little more seriously.
"But most importantly, it conceals the consistently demonstrated mystery of "long makes straight". To fix a wayward cut or create a straight cut, lay the saw down until the work sees more saw. Very simple. Relying on the kerf to guide your saw is a recipe for frustration. ... "
Not sure how something can be "consistently demonstrated" and a "mystery" at the same time. (??) As previously indicated, the key to cutting dovetails with a minimum/zero set saw is an accurate start. In other words, any "correction" needs to be made at the outset. And it can be, as demonstrated by the Edwardian era "London dovetails". Both angled cuts which define the socket into which the pin will fit are started from the same line/kerf. This is accomplished, when starting the second cut, by registering the saw at the start of the already established kerf, then lightly beginning the second cut while holding the saw at the desired angle (or vertically if you've shifted the drawer side so the second cut is defined by a plumb line). Once started, the saw wants to track the newly established kerf in a predictable and satisfying manner. I only mention it in this context, because I believe it demonstrates the principle of this approach in a fairly dramatic fashion.
I belive starting a cut with the idea that it can always be corrected mid-kerf, and/or can be remedied by paring later, is the recipe for frustration. Yes, I have needed to correct cuts by paring, but I try to keep that to an absolute minimum. Experience informs me that the more paring/fiddling one introduces, the more likely one is to be dissatisfied with the results.
"P.S. I consider it a great honor to be read by Don McConnell. He is without a doubt my all tiime favorite galoot. I mean, anybody know owns an 18" Gabriel backsaw has got to be someone special!"
I genuinely appreciate the kind words, but apologize if I've said anything to lead you to believe that I own an 18" Gabriel backsaw. I have owned an 18" Disston backsaw, so mis-spoke if I said otherwise.
Regards,
Don