If you're a hobbiest guitar maker, or you're like me, and do it for a living, but build in small quantities, here's why I think you should consider cutting your fret slots with a handsaw as a viable method. The steps listed below will help you to advance your guitar making accuracy, and versatility, without sacrificing 'Wilbur', your beloved piggy bank, to the over inflated market of guitar supply houses.
If you've ever bought fretwire more than once, and if you haven't yet, you will, you might know that the tolerances tend to vary slightly from one manufacturing run to the next. For this reason, I tend to buy fretwire in rather large quantities, at a time, though it never seems large enough, but it is only reasonable, feasible, and cost effective for me to keep so much on hand at any given time. That being what it is, the inevitable always happens - eventually I run out, right as I have a deadline coming down the pike, and am forced to reorder. When that happens, rarely are the spec sizes EXACTLY what they were on the previous run, and that can cause some issues. The main dimension about which I am concerned is the tang width (that is, minus the barbs), and I like to have my fret slots about 0.001" - 0.002" larger than the tang width, but if the tang width changes from run to run, I can't really make my fret slots an absolute width.
Because that is the case, I have abandoned the CNC, or the table saw for cutting fret slots, and have instead turned to my trusty, modified, dovetail saw.
Cutting fret slots on a CNC with a micro end mill is great, but as I mentioned before, I'm a small guitar maker, and having to buy more micro end mills in different diameters as fret tang sizes vary gets expensive, and time consuming, especially when factoring runout into the equation in order to calculate your finished slot width. Not to mention, I seem to have the misfortune of breaking those pricey little end mills a little too often. The table saw is another great method, but with similar drawbacks to those mentioned about the CNC (i.e. Multiple blade kerfs).
The handsaw, and its secrets, and nuances seem to be dying in this day and age. People look at them as an antiquated means of cutting - one used by their grandparents, and great grandparents, or as a means of decoration hung strategically about the shop to herald days gone by (a sad use for what could be functioning useful tools, if you ask me). But the truth is, a handsaw is just as relevant today as it ever was. The reason I love to use a handsaw to cut fret slots is for its ability to quickly and easily morph from one kerf size to another, and back again. It's not quite the flick of a switch, but it's pretty simple once you know what you're doing. The saw I choose to use for sawing fret slots is a relatively inexpensive dovetail saw that I modified to my needs. This saw was made by Crown, and I believe I paid somewhere around $18 USD for it. Since a dovetail saw is actually filed as a rip cut, and cutting a fret slot is technically a cross cut, I refiled its teeth to less aggressive, more cross cut conducive rake.
I did this with a saw sharpening file that can be had for around $5 USD.
A saw sharpening file is actually a 6 sided file, so the small point on each side is able to cut down the bottom of each a valley between the teeth.
The final two tools I used were a ball peen hammer, and a saw set. I've been given several ball peen hammers over the years, so that cost me nothing, though you can pick them up pretty cheap at second hand stores and flea markets, maybe not more than a couple bucks. The saw set cost me around $8 USD at a flea market as I recall, but a new one can be had for around $25.
Once I had refiled the teeth, I hammered out all the set of the teeth. This brought the kerf down to the thickness of the plate, which in this case was 0.02". That is the exact thickness of the tang on my current run of fretwire. While I could leave the slots size-on-size, I find that creates to much of a wedging effect, and induces too much back bow, or more than I like to see, when the frets are installed, and on top of that, a saw with no set is terribly inefficient at clearing the waste material making for slow sawing. So I want to add somewhere in the neighborhood of 0.002" of total set.
To do that I use the saw set, and very gently squeeze. If I measure the kerf as being too wide, some gentle taps from the hammer help to bring it back into place. To check the kerf size, saw a slot, and check it with feeler gauges.
Once you have what you want size wise, you're ready to saw your fret slots.
A little more on the handsaws in question: a western saw is a push cut saw that requires set teeth to work effectively at clearing waste. A Japanese style saw is a pull cut saw that uses two opposing rows of teeth to do the clearing with the teeth set flush to the plate of the saw, and the saw plate is actually tapered in thickness thickest at the edge of the teeth, and thinner at the spine. The set of the teeth on a western saw allows the saw to cut a wider kerf than the saw plate, and allows clearance for the plate to avoid friction. The tapered design of a Japanese style saw plate does the same thing. All of that to say, even though you might see people on luthier's forums saying how much better the Japanese pull saws are than western push saws, you should buy a western style saw as the one I mentioned above. But why?
Here are three good reasons:
•You can easily adjust the set
•They are quicker and easier to sharpen
•They are plentiful, and can be found inexpensively
So why do we always see people on forums downing western style saws? Because they buy them from luthier supply houses, where the saw plates are the exactly thickness of the needed kerf, so they don't allow for any set, they come with improperly filed teeth rake, and they don't come sharp. All of those reasons make for a saw that performs poorly, which is why people flock to the Japanese style pull cut saws. Japanese style saws tend to come very sharp right out of the box, and don't require set, so they saw quickly at the very first moment of use.
In conclusion, I'm not saying you need to saw your slots the way I do; I'm not even saying that you have to use a western style saw over a Japanese saw over a western one. The aforementioned paragraphs are my thoughts and reasons for doing it the way that I do, and maybe it will help you look at the subject in a new light, and maybe give your arm a workout in the process.
Until next time,