Graminho, in my opinion a sweet word, is how we call this traditional marking gauge in my mother language. From Wikipedia, "A marking gauge is used in woodworking and metalworking to mark out lines for cutting or other operations.". Wikipedia also tells you: "The purpose of these gauges is to scribe a line parallel to a reference edge or surface.". You have probably already used a primitive version of this tool: when you pick a pen and draw a line parallel to an edge, by pressing your finger against the edge to maintain a constant distance of the pen's tip to the edge.
I always wanted to have one, of course :). But the ones I found were quite expensive, and that is what usually puts me to think (there's a saying which states something like "the need makes the inventor" ;)).
So I looked at my small material stock and this squared section 1.2x1.2cm (1/2 inch), 100cm (40 inches) long piece of wood draw my attention. I picked Inkscape (excellent OSS 2D vectorial drawing application) and designed this marking gauge using only this wood stick, a nail and white glue (also known as "glue for wood").
Before starting with the construction, I did a paper model of the headstock, just to have a feeling if the measures I choose would adapt well to the hand. They did.
Step 1: You Need These Tools and Materials
- thin wood saw (or a metal saw, as I used)
- chisel, any from 5mm to 12mm wide
- wood hammer and a normal (iron-head) hammer
- drill capable of holding 1mm (1/25inch) thick bits (a drill press can help a lot)
- file or sand paper, something equivalent to grit 240 or higher (it's "medium")
- table or static cramp is useful
- 100x1.2x1.2cm (40x0.5x0.5inches) piece of wood (square, long)
- 1 flat head nail, 1.4mm (1/20inch) thick, 20mm (3/4inch) long
- preferably white glue or wood glue, but contact glue, paper glue or any other "common" glue will do (I don't recomend super glue because it dries too fast and it's too dangerous for such a simple job)
Step 2: Cutting the Body Parts
Start by cutting a 6cm (2.4inches) long piece of the stick (use the ruler and the saw, of course :)). This will be your "master" piece, and you'll use it as a measure to cut all other pieces, saving time and assuring that they will be all about the same length. The exact length of all pieces, 6cm, is not critical, but they should be all the same length.
Cut another 12 pieces, by holding the master on top of the stick, aligning the start, and making a cut mark with the saw. Then you can take the master out and cut the stick by the previously done mark. Repeat until you get 12 pieces plus the master (13 in total). Sorry for the not-at-scale hand drawn picture; it has been some time that I made this gauge and I have not taken as much photos as I would like.
In the end you are left with a stick of around 20cm (8inches) (if you started with one of 100cm (40inches)). This will be your beam.
Using the file or grit paper sand the cut corners of all pieces a little bit, mainly to remove any sharp edges left by the cutting.
Step 3: Gluing and Making the Headstock Hole
Gluing is an interesting art by itself. If using white glue, spread the glue evenly on one side; wait 2 minutes and then press the pieces together, hard, and let them dry for an hour or 2. You can use a cramp if you want, but don't press too much; just keep them tight. If some glue comes out by the joints, don't remove it immediately; wait for it to dry a little until it gets "non-wet" and use the chisel or a knife to cut the excess.
Pick the glued pairs (after drying) and do a gluing simulation, by assembling the pieces as if it were the finished product (2nd photo). With the pencil make 2 marks in the corners as show in the photo, on the pair in the middle layer; you'll have to make a cut in this pair for the headstock hole.
Disassemble and put the marked pair in the cramp (3rd photo). Then make 2 small, around 6mm (1/4inch) deep cuts on the marks. Pick the chisel and remove the center block of wood. This will be the hole for the headstock locker.
Now glue the bottom layer of the headstock to the middle layer (4th photo). With the glue still wet, insert the beam to adjust and align the piece pairs. The beam is used as a spacer. Adjust the pieces so that the beamer fits without lag and without being too pressed. Make the beam run smoothly through the headstock.
To help the beam to run free, you should:
- pick the thin side of the beam and position that side such that it is lower than the side pieces.
- not press the layers too much when gluing, we want to let the glue create a tiny little spacing between the layers
Finally, glue the top layer (5th photo). Leave it for a few hours to dry and sand the sides to make them smoother and more flat (don't sand too much).
And you're done with the body (6th photo)!
Step 4: Building the Headstock Lock and Finishing the Beam
Still remember the "master" piece? You will now convert it into the headstock locker!
Take a look at the 1st photo: clamp the piece in the cramp just to hold it in that position (don't press it), point the chisel's blade at half size, and give it with the wood hammer. It will crack top to bottom.
Pick one of the halves and, if not already, sand it such that on side gets a bit thicker than the other (it's easier if you start by removing some material with a sharp knife, then sanding for smoothness). This difference in thickness is crucial for the lock to hold in place when locking the beamer/headstock. Try the lock in the headstock to see when it is OK.
Sand also around, to make the corners and edges round, and remove any pencil markings.
Now it's time to finish the beam. It is missing the ~~nail~~ marker pin. If you hammer the nail directly in the beam the wood will crack. To solve this, you need to drill a hole first. Then you can hammer the nail without any problems.
The drill bit should be slightly thinner than the nail you have, otherwise it will be loose.
Ahhh! Sorry, only know I see that you need another tool: a normal hammer! You can't hammer a nail with a wood hammer :). But I'm sure you have an iron-head hammer around :).
And that's the end! I hope I was able to explain myself clearly. I had a hard time translating all of these "bricolage"-specific words into english. If you have suggestions for other words or terms, I would love to know about it.