Carpenters Use Scribing to Ensure a Perfect FitLast Updated:[4/3/2007 5:51:06 PM]When it comes to carpentry and woodworking, there is simply no substitute for precision, and precise measurements are one of the keys to success. In a perfect world, all surfaces would be smooth, flat, clean and free of imperfections, but in the real world carpenters must deal with all manner of imperfections in the materials with which they work. Some of the challenges to getting a perfect fit include surfaces that are not level, not plumb or irregularly shaped. To overcome these all too common problem, carpenters use a technique known as scribing to ensure a good fit. There are many times when scribing is appropriate, and there are several ways to accomplish the goal, but the general idea is to use one surface to guide the pencil while the surface to be joined is marked. The carpenter can then cut along the marked line and join the two pieces together with a perfect fit. In order to use the scribing method it is important to first gather the tools and supplies that will be needed. These scribing tools include the following:
If the object to be joined can be positioned, the direct scribe method can be used. To use the direct scribe method, first position the object to be scribed. The position will depend on the object itself – for instance a corner shelf would be placed against the wall and leveled, while a wall mounted cabinet would be leveled in both directions. After the piece is in place, a compass or a scriber can be used, along with a carpenter’s pencil to transfer the angle and shape of the object to be fit onto the object being scribed. The tool should be opened so that the gap between the points is equal to or greater than the widest part of the gap between the two objects to be joined. The metal point should ride against the surface as the pencil marks the scribe. When using this method it is very important to keep the compass or scriber points level or plumb. If the gap is very small a pencil can be used, laying the pencil flat on one surface, with the point resting on the other surface, sliding the pencil along to create the scribe. This will produce a scribe of approximately 1/8”. If a wider scribe is needed, a small stick or board can be placed underneath the scribing pencil, thus increasing the width of the scribe by the thickness of the board or stick. The last step is to cut the scribe line using a saw. The type of saw to be sued will depend on the tools available and the situation, but generally a handsaw or circular saw will be used to cut straight lines, while a coping saw or jigsaw will be needed to cut irregularly shaped lines. After the cutting is done the fit can be tested and the process repeated if necessary. In some cases the direct scribe method will not work as well, and the indirect scribe method should be used instead. For instance, most shelves, cabinets and countertops, which are designed to fit between two walls, will not allow for the positioning of an object for a direct scribe. There are two options for this type of situation – measure and transfer or scribe a template and trace. The measure and transfer method involves holding a carpenter’s square with the long end against the back wall, sliding it into the corner and measuring the gap between the rule and the wall at what would be the furthermost point of the shelf location. That measurement is then transferred to the shelf board to crate a tape, and the line is then cut to fit. The template and trace method involves cutting a piece of scrap wood or cardboard so that it is the same width as the shelf, while still short enough to easily fit between the walls. The scribe is positioned as in the direct scribe method and the angle is cut and tested for fit. When the fit is perfect, the template is laid on the real shelf, the back edges are aligned and the angle is traced. The shelf is then cut along the traced line, ensuring a perfect fit. |
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