OK, I’ll go down this rabbit hole. These types of tools are very personal to the woodworker / maker. I would be hard pressed to say that one or some are better than others. It’s a trust relationship that we as furniture makers have come to understand. It does not take long for a novice woodworker to figure out that the accuracy of laying out joints can only be achieved by quality tools. For example, the pencil. First, we have the carpenters pencil that we all know and love and probably have an abundance of around our shops. It’s great for marking out 2x4 for a deck, studs for a wall or making a shopping list for the big box stores…but that’s it. The only application for these type a pencils in a furniture shop would be rough layout lines for breaking down lumber. Next up, the old tried and true #2. You know the one we all stuck behind our ear, in our hat or pocket, etc. These were the ones our dad’s used when we were young and he was our Norm Abraham. It never failed, unless the tip broke, was wore down to a carpenters fat line or …or the eraser was gone! I must have twenty five or thirty of these pencils on a shelf in a can and not a one has the eraser. Someone must have made a mistake or two. They are good pencils if the tip is sharp, very sharp. You need to have a nice clear and crisp lines for joinery. Once the tip gets used, the line starts to widen. Not ideal. My choice is a .3 or .5 mechanical pencil. I get very consistent, clear, clear lines. The down side is the eraser.
Next in line, are your squares, combo squares, tri squares, layout rulers, setup blocks, straight edges etc. I bet there is no shortage of these tools in your shop. We seem to collect them over the years. They serve us well, but we have our favorites or some we designate for certain tasks such as mortise and tenon layout, router bit height, table saw fence distance or blade perpendicularity or just drawing a straight line. These are the tools that we treat with a sort of reverence, like my Woodpecker’s 641 square, Incra Precision T-Rules and Starrett 4” Double Square. As mentioned above, a good square or marking layout tool is as only as good as a quality pencil. Setup blocks are some of my favorite tools. They produce rapid repeatability that is guaranteed. They are very simple to use, just add the block thickness to the desired depth and strike your line. Simple and very, very accurate.
Moving on to the marking knife. I have at least 5 and I have a favorite. I believe some are better at some tasks than others. They require some maintenance, sharpening when needed. The bottom line is it all depends on you. What you are comfortable with or what you were taught to use from trade school or your mentor. The blade must be sharp. This allows the blade to sever and cut the wood fibers so the blade does not wonder or stray from the straight edge due to the wood grain. They must be a flat back so it can register against the straight edge or the work piece. The handle must be comfortable in the hand. Make sure that the handle is not completely round… or else it can roll right off your workbench, ask me how I know! Some marking knives come in a left and right version. I am not a big fan of these because you need to buy them in a pair. The length of blade also dictates how thick of a work piece you can mark against. If you routinely work with one inch thick stock and your marking knife blade is only three quarters long…that’s a problem.
So in wrapping up, I just skimmed over the surface of this subject. I did not include all the tools but just some of the basics. I hope you enjoyed this article are were able to find some information useful.