Reach For A Stanley (January 2009):
The No. 48 Swinging Fence Match Plane (by Christopher Schwartz)
When it comes to making a list of handplanes that are both simple and ingenious, the Stanley No. 48 is near the top of that heap.
That's the good news.
The bad news is that the No. 48 works better on paper than it does in a furniture-making shop.
That's not to say that the No. 48 is a clunker. Far from it. You just have to know the limitations of the tool before you assume it will effortlessly make all the tongue-and-groove maple flooring for your living room. Because it won't - unless you are a masochist or a body builder.
Before we discuss the tool's limitations, let's discuss its engineering brilliance. The No. 48 is a clever metal version of a wooden "come-and-go" plane - which was two planes in one. One side of the plane would cut a groove. Turn the plane around and the same plane would cut the matching tongue. The "come-and-go" was less common than having a set of two matched planes - one for the tongue and one for the groove.
The Stanley No. 48, introduced about 1876, combined both the tongue and groove functions into one tool. And the way you switched between the two functions was by swinging the fence 180°. With the fence locked in one position, one cutter is exposed and you cut the groove. Flip the fence around and two cutters are exposed to cut the tongue.
The No. 48 cuts a 5/16" x 5/16" groove in stock from 1/4" thick up to 1-1/4" thick. The tool centers the groove on work that is 7/8" thick. Once your work exceeds 7/8" thick, you need to swap out one of the cutters for a wider one (included with the original tool but usually missing).
The tool must have been successful because it was offered up through World War II, but that doesn't mean it's perfect. I've had one in my tool chest for about five years and have found it both delightful and frustrating at times.
First, you have to pick your stock with care. Straight-grained stock is essential for the tool to work well, otherwise you'll just make a mess of things if you end up working against the grain. Also, hardwoods can be a real challenge for the user. If you set the tool for an easy cut, you'll spend a long time making one tongue. Set it to cut aggressively and you'll find the tool bogs down quickly.
I reserve the tool for making joints in softer woods - it's brilliant in soft pine and works fairly well in poplar. These are traditional secondary woods for drawer bottoms and cabinet backs. But if you try to use the tool on dry white oak (for a floor) you're in for a real workout.
One of the other weaknesses of the tool is the swinging fence itself. It tends to wobble a bit in use, and the pin that secures the fence isn't always strong enough to keep the fence in place during a heavy cut.
Here are some other tips for use: Ignore the fancy knob. When you use the tool, place one hand on the tote and use that hand to push the tool forward. Place your off hand on the fence to press it against the work and place your thumb behind that nice-looking rosewood knob. The plane will be far more stable with that grip.
Also, start your cut at the far end of the board - like you would use a plow plane. Gradually make longer and longer strokes until you are planing the entire long edge of the board. Keep planing until the plane's integrated depth stop kicks in and stops the tool from cutting.
Here's the other thing to consider: When you make these joints with the No. 48, you need to pay attention to the face side when you work. 
Because the joint will rarely be truly centered on the board, you need to be aware that the face side of the board changes depending on what joint you are cutting. When you cut one half of the joint, the face side will be facing you, the user. When you cut its mate, the face side will be facing away from you. This is critical when making a cabinet back that will show.
Despite these limitations, the tool is great fun to use and is a fun parlor trick to show your power-tool friends. Plus, it avoids the major problem with wooden-bodied match planes - usually one of the matched pair has gone missing, making the orphans virtually useless on their own. The No. 48 always has both the tongue and groove planes on board.