A straightedge is a handyman's tool, and fitting one to your drafting table can be an excellent way of having a convenient place to cut or draw an accurately straight line. If you want to put a straightedge on your drafting table, there are a number of difficulties which you will have to overcome. The first is that, while a straightedge which is accurate and very useful, one which is not completely perfect is virtually useless and will only serve to mess up your work. In order to make a straightedge, you will therefore need to have some good home improvement skills to manage this job.
Step 1 - Cut the Wood
You will need some good lumber, which is preferably straight-grained, and durable. You don't want a wood which moves when your drafting table is in an area with strong humidity. Take a tropical wood without any knots, and dry it thoroughly, or have it dried. This should leave you with a nice, straight-grained piece of wood. Once you have this, you will need to cut it to the size of the drafting table. It is probably best to fit your straightedge on to the side of the table, so that it can be placed along the edge when not in use. Saw off both ends of your wood, and then cut the width to the size you require.
Step 2 - Plane the Wood
You will need to ensure that the flat side of your straightedge is completely level. Begin by using a planing tool. The longer the plane, the better your edge will be. Remove a few strips beginning at the middle of the side you want to be straight, and then remove strips traveling from one end to the other without moving the plane. Place your spirit level on the edge to check that it is completely level.
Step 3 - Cut the Curve
On the other side, use the edge of your drill to mark out a slow curve. The ends should be tapered, with the largest bulge directly in the center. You may have a tool which can help you to make this curved cut, but if not, shave off the curve slowly and gradually until you are sure that the side is good. Test your shapes by marking out the edge on a piece of paper, and then rotating the piece 180 degrees. Place the same side up against your mark, and you should be able to determine if it is 100 percent straight.
Step 4 - Adding to the Drafting Table
Drill a suitable hole on the side of the straightedge. Use a screw to connect your edge to the table, and tighten using the drill. You should be able to move the edge around the table, with the single screw holding it in position when it is not being used.