From PDF to MDF: Making a guitar body routing template part 2

A couple of days ago, where I described the first stages of turning a PDF plan into an MDF template, we got as far as having a printed plan. Now let us turn that printed plan into a template we can use for routing the body shape.

The last step in the last episode was to double check all the measurements – well in my experience double checking is never enough. Stop what you’re doing and go and check it again.

First we need a piece of MDF. The recommended approach to doing this is to first make yourself a master template, and then use this to create a working copy of the template. For the master you’d use 9mm (because it is easier to work with and to sand to shape) and for the working copy 18mm (so you’ve got enough depth for the router bit to run against). Because this build is a one-off I’m just going to go straight to 18mm MDF.

Many people recommend gluing the paper template to the MDF, but I have previously had problems with the glue causing the plan to expand slightly as it dampened. I suspect you could overcome this problem using spray mount adhesive but I now choose a different approach. I tape the plan down to the MDF at four or five points and then hatch lines across the edge all the way round. Once the paper plan is removed it is a piece of cake to join the ends of the lines.

Then it is a matter of using a bandsaw or jigsaw to cut close to the line…

…and finish of by sanding to shape – continually checking against the paper plan.

A word of warning here. Spend time making sure the edges of the template are smooth and exactly as you want them to be. Don’t just look at the edges – close your eyes and feel them too. The first time I made a template I left a couple of bumps, knowing that I could tidy them up when I was sanding the final body. I quickly learned that a sanding job that would have taken a matter of minutes on thin MDF became a herculean task when I was doing it to 1.75″ of hardwood. Get the template right and you don’t have to do it later!

Now you’ve already checked the measurements three time but you know what… Do it again before you put the template anywhere near that chunk of expensive timber.

From PDF to MDF: Making a guitar body routing template Part 1

One of the questions that I have been asked a couple of times is “Where can I find a guitar body plan and how do I make that into a router template”? This series of posts will outline how I do it. It definitely isn’t the only way. It may not be the best way. But it is the cheapest and consequently they way I do it.

The first challenge is finding a good accurate plan. My first port of call for Fender style designs would be TDPRI. There are also several excellent plans available over at www.gitarrebassbau.de.

Most plans are available in PDF format, and that is what I’ll be talking about primarily, but occasionally you’ll find a plan in DXF format (AutoCAD’s interchange format). In these cases you can use the free online version of AutoCAD (requires registration) to convert to PDF.

Download and install Inkscape, a free vector drawing program. Head over to http://inkscape.org/ and download the version relevant to whichever operating system you prefer. Once you’ve got it installed fire it up and we can get started.

The first decision to make is what orientation of paper would best fit the plan. For most guitar body shapes (Strat, Tele, Jazzmaster, Les Paul, etc) I’ve found that four landscape sheets (2×2) is about the most efficient, but for a larger body shape you may find you need six portrait (3×2).

In Inkscape, to change the document orientation, you choose File -> Document Properties (or Shift-Ctrl-D).

Next we’re going to import the PDF plan into Inkscape. Choose File -> Import (or Ctrl-I) and select the PDF file. Accept the default suggestions in the next step.

Now we could just print off the plan just as it is, but to help align the sheets as they’re stuck together I like to overlay the plan with a pattern of diagonal lines.

To draw the lines;

  • Select the Bezier/Straight Line tool (Shift-F6)
  • Click once then hold down the Ctrl and drag the mouse out diagonally. Click a second time and then press enter.
  • Duplicate the line by pressing Ctrl-D and then flip it horizontally by pressing “H”. This gives us two diagonal lines at right angles to each other.
  • We now want to duplicate these lines many times over. First we need to group the two lines into a single object so select them both and press Ctrl-G.
  • With that still selected, choose Edit -> Clone -> Create Tiled Clones.
  • We want 100 rows and 1 column (to repeat the pattern 100 times).

  • On the “Shift” tab we define how much each subsequent copy should be moved. For “Shift X” choose 5% per row and 0% per column. For “Shift Y” use -100% for both row and column.

  • Click the “Create” button and you’ll find yourself with a pattern of intersecting diagonal lines.

  • Drag to select all of the lines and group them into a single object (Ctrl-G).
  • Now drag the grid pattern over the top of the plan. If it is not big enough, you can grab any of the corners to resize.
  • Select both the plan and the overlaid grid pattern and group these together (Ctrl-G).
  • You can now grab the whole thing and move it over the page image, and print overlapping areas of the plan.

You may find that the lines on the plan are much more faint than on the grid. You can correct this by selecting all of the items (Ctrl-A), pull up the dialog that allows you to change fill/line properties (Ctrl-Shift-F), on the “Stroke Paint” tab, make sure the stroke colour is set to black. On the “Stroke Style” tab set the stroke thickness to 1px.

Then it is just a simple matter of trimming the edges (assuming your printer doesn’t print right to the edge) and taping them together. And in best Blue Peter fashion, here’s one I prepared earlier.

And now comes the most important step of all – take a good ruler and CHECK IT IS THE RIGHT SIZE. Please don’t ask me how I know.

The next instalment will cover the making of a template from the paper plan.

Additional resources

BigPrint is an excellent application that can do all of the above for you, working from a picture or photograph. It is not free but is well worth the money.