simple and precise shopbuilt slotting jig

[Bob Hammond]

Hi, since my left forearm has been in a cast and is of limited use for holding things, I made a new slotting jig that I can use one-handed. It is easy to build and use, and is not expensive.

I use an asian style saw , the Vaughan Bear Saw BS250D that cuts a kerf of 0.0226" (or better yet the single-edged BS250H). A 1/8" thick strip of wood is stuck on to one side of the blade with woodturner's double-sided tape, leaving only the teeth exposed (about 1/8"). This strip limits the depth of cut.

The pictures show the layout and use of the jig (I think I'll do it again with better materials, someday). The base is 6" wide x 24” long x 3/4" thick, and the front fence is 1-1/2" wide x 5/16" thick. The back fence is 1" wide x 3/4" thick, and is placed parallel to the front fence at 3-1/2" distance. The sawfence that bridges the baseboard is 1-1/2" x 1-1/2", with a notch of 3/8" cut into the underside, and is carefully squared to the front fence. A piece of magnetic tape was applied to the sawfence to guide the sawblade. The folding wedges are about 5-6" long so that they can be easily set or loosened with one hand, with the flatter one cut to width as needed for the fingerboard blank. On the piece of (green) tape on the front fence, an index mark was incised at 1/4" away from the sawfence, so that it is easy line up the fullsize paper template (generated by Fret2find (http://www.ekips.org/tools/guitar/fretfind2d/).

To use, the fingerboard blank is placed and shimmed up just above the front fence (in the pics, I used a yardstick), and positioned so that a fret marker on the paper is lined up with the index mark (note that this makes a 1/4” offset). Then the wedges are placed to snugly clamp the fingerboard, and the sawblade is placed on the fence and stroked until the depth-limiting strip contacts the surface of the fingerboard. Easy!

[Bob Hammond]

ready to cut

[Bob Hammond]

closeup of the fence, and paper template aligned to the index mark

[Bob Hammond]

halfway done, using only one hand! It's best to choke up on the handle of the saw, to the lock-knob. The paste wax lubricates the magnetic tape on the fence to make the cut easier.

[Peter Wilcox]

Thanks Bob - lots of useful ideas for me here, even though I have two hands. I never thought of using a sacrificial paper template - it will be a lot faster than marking out each fretboard, and probably more accurate.

[Bob Hammond]

Peter, there are a couple of things to bear in mind to print and align the paper template. I'll take a pic or two tomorrow and post them.

[Peter Wilcox]

I already printed one out (a 34" bass scale) just to see how it went. The fret spacing seems to be accurate on each sheet, as near as I can measure, and I think if I align the top and bottom grey margins on each sheet, and keep the center line straight when I tape them together it will be good for the whole fret board. But any tips you have would be appreciated.

[David King]

I like to use a place like Kinko's when possible. They have a nice printer that can do 11" x 48" and it costs $1.65 a copy. The paper they use seems a little better than your average inkjet. You just need to upload the pdf to their website or bring it on a thumbdrive.

[Peter Wilcox]

The nearest Kinkos is 70 miles away. However, I can print up to 12.95" x 129", but don't have the paper on hand. I can pre-tape several sheets together, or I can get some roll paper and try that.

[Bob Hammond]

David, your alternate way is certainly accurate and good for production work, but not everybody has the money, space, or need to install a mill.

Peter, here's how I patch the template together and place it on the fingerboard:

1. Cut off the whitespace on the margin so that template lines go to the edge of the paper (see the right sheet here).
2. Cut tiny windows on the margin box, and along the centerline of the template. (A handheld plier-type holepunch could save a few moments here.) These windows will allow you visually align the template.
3. Glue or tape the page overlaps together. I use the gluestick because it will allow a repositioning or two if I don't get it right. Cut away any excess paper.
4. Scribe a centerline down the length of the fingerboard, and then give it a light coat of 3M Spraymount. I suppose the gluestick could be used instead of the 3M Spraymount (it's much neater, cheaper, & easier to find too), but I haven't tested about how to remove it after cutting.

5. Put a sheet of waxpaper over the fingerboard, lay the template over it, and then draw the waxpaper to the side as you lay/press the template on to the fingerboard, using the windows to align the template to the scribed centerline.

One other thing that I see in the pic of the jig, is that the wedge sets on either side of the sawfence are oriented opposite to the other set. This helps to firmly hold the fingerboard in the jig, in that a rightward movement is opposed by the right-side wedges, and correspondingly so, a leftward movement is opposed by the left-side wedges.

[Peter Wilcox]

Thanks Bob. I think I'm going to print it out as one piece, then attach it using your cut-out idea to align it on the fretboard.

[Bob Hammond]

I'd do a one-piece too, if it was convenient.

Hmm, I wonder if you could roll the template around a cylindrical tube, maybe such a pill bottle, so that it could be unrolled on to the fingerboard blank. But I'll try it out on scrap first, of course.

[Bob Hammond]

I forgot to mention about how to easily remove the wood strip that was taped with the woodturners tape which is very tenacious after it's there for a while. Just heat the blade on the other side with a clothes iron, and the adhesive will soften enough to remove the strip easily and without damage to the saw (or your fingers). Then clean up the adhesive residue with spirits of naphtha.

[Jason Rodgers]

I've been using fretfind2d to print templates for basic layout for a while, and for fret slotting on my first. I cut diamond "windows" in the template centerline with a knife for matching the template to the scale drawing or fretboard, but I didn't think of doing this on the sheet line-up lines for ensuring that separate pieces are well aligned. This is especially tricky on the eyes when using multscales fretboards. Thanks, Bob. You can learn good things here every day!