I have used marking gauges for several years now, and have had mixed results. My biggest complaint has been with the cutters. The ones I have used had a small nail sized cutter that would tend to get caught in the grain of the wood when marking. This was not only frustrating, but created inaccurate lines. I found a recent article in ‘Fine Woodworking’ that had a simple design that works better than any I have tried.
Here are three different gauges I have used. The top two use pins.
Here are the parts for the one in Fine Woodworking. The fence was made by cutting a single piece of stock into 3 sections, and then regluing to create an absoluting square mortise for the bar, while retaining the original grain orientation. The bar is then made to exactly fit the mortise. A mortise is made in the bar to accept the cutter (made from old sabre saw blade) and the wedge. A threaded insert in the fence allows a brass thumbscrew to exert pressure on oak plug to hold the bar in place. The spear point bevel on the cutter does not wander and works like a charm.
Here are three different gauges I made using the 'Fine Woodworking' April 2010 design.