This is where the fun begins! You get your first look at the project-to-be and you can work out the bugs in the overall look of the piece without laboring over the details. Approach concept sketching by giving your hand ‘free rein’ to draw and redraw any inspirations that comes to mind. This is not the time to worry about perfect symmetry, properly scaled portions, crisp lines or exacting curves. You can take care of all that later when you produce the mechanical drawings. Do not however go on from sketching to drafting until you have something you really like. It’s too time-consuming to make major design changes at the drafting stage.
Choose an artist’s sketchbook and a soft #2 lead pencil with a pink-tipped eraser. Avoid using anything harder because their lines are difficult to erase from typical sketch paper. Hold the pencil lightly and just move across the page until something comes to you. Allow your arm to move with your hand as you make long lines and turn the sketch pad as you naturally sweep your wrist across the paper when drawing angled lines.
One of the benefits of doing ‘freehand concept sketches’ is that you can easily create a series of ‘what-if’ views. Instead of redrawing the form over and over, simply trace it onto a piece of translucent paper, leaving out the areas that will be changed in the ‘what-if’ views. Or you can photocopy as many basic outlines as you’d like and then flesh them out with your new design idea.
Once you have settled on a concept sketch that comes closest to what your idea is, it’s time to assign some dimensions to the project. By setting out the design to scale in a mechanical drawing, you can see clearly how the size and shape of components relate to one another. Methods and sequences of joinery also become more obvious. These working drawings are a bridge between your freehand concept sketches and a master cut list.
Drafting basics –
These skills are mostly common sense: make sure your board is free of lead and eraser debris before taping paper to it. Align the bottom of the paper to the parallel rule and then secure it to the board with a piece of tape in each corner. Keep a scrap piece of paper between your hand and the drawing to avoid smudging your work. Use a brush to wipe away eraser debris, not your hand. Once you establish a baseline on your drawing, draw any degree angle to it using either angle templates or a protractor and straightedge.
Begin the angled line precisely on a dimension mark by fires holding the pencil to the mark and then sliding the template or straightedge to it. if you reverse this process, parallax can play tricks on your eyes, causing you to misjudge the placement of the pencil. Draw out a waver-free line by tilting the pencil slightly into the corner formed between the edge of the template and the paper.
A mechanical drawing is nothing more than a happy meeting of lines that indicate the outline of an object and where measurements are being made to. Unless these lines vary in some way, the drawing can be difficult to read.