Whenever we do a project that has the potential to be built again, or if the design is somewhat difficult, we'll spend the time to build a jig. This is a process that pays back big dividends, and has been practiced for hundreds of years. In the first instance, it makes sense to speed up the process of duplicating it. This results you from having to record all the dimensions and engineering that went into the piece.
A very big time saver. In the second instance, I would rather make a mistake on a piece of plexiglass or MDF, than on an expensive piece of wood. (wood does not grow on trees you know). Mentally, it's easier to create a shape on a piece of plexiglass, or MDF, simply because it's "only a jig". Somehow, that seems to take the pressure off. Cutting the final piece can keep you from moving forward on a project, because you fear making a mistake. I know that sounds silly, but it's something I've witnessed, (and done), on many occasions. Jigs give you the confidence to move forward, knowing it's right.
It's much like seeing a person go from helper to mechanic over night. Same person, same knowledge and experience, just a new attitude. They just did not realize, they had the talent and knowledge. It really is amazing to watch a person's transformation because they finally realized they knew how to do it. Now they're working with confidence, instead of fear. They stop second guessing themselves, which leads to less mistakes. Once the jig is created, and it's perfect, making the final piece or duplicating it, is a breeze. The fear of mistake is eliminated in the jig making process.
This is especially true when trying to duplicate something a couple years after the first one. The toughest part there, is remembering you have a jig for it, and where it is! Jigs can be templates, or can be a method of holding the work piece to allow carving or machining. Jigs designed to hold things can be altered to make the jig itself more useful. As the project progresses, new ideas come to mind, which brings about change to the jig. It's a case of building the project and the jig together, as you move forward. If you're not already doing so, you should add jig and template making to your woodworking repertoire.
Source by Lee Jesberger