A good option to buying moldings off the shelf or having them custom-made at a millwork shop is to cut your own in your own shop. In addition to saving quite a bit of money, routing your own moldings may be a sensible alternative for your project if you can't find premilled molding in the profile you like, or if it isn't available in the same wood species as the rest of your woodwork. To make moldings, you'll need a router mounted in a router table and and an assortment of bits (or, alternatively, a table saw outfitted with a molding head cutter). A third tool that's ideal for making moldings is a stationary shaper, which operates on the same principle as a router in a router table, except a shaper has a much larger motor and a thicker spindle. Shapers are designed to spin large, three-bladed cutters that look like giant router bits. Cabinet shops use them all the time for manufacturing raised panels and door frame joints, but shapers aren't common home shop tools because they are expensive.
A router is a safer and less expensive tool for making molding than a table saw and molding head cutter. Router bits take much smaller bites of wood, so the cuts are safer to make. Plus, router bits come in scores of different profiles to mill all or part of virtually any molding profile you can imagine. When the tool is used correctly, the profiles produced by a router are as smooth as those made with a shaper. As far as cost is concerned, top-quality routers are readily available and relatively inexpensive. It's worth spending a little extra to buy a router that can be run at variable speeds so you can run it more slowly when using larger bits. Also, invest in a router that will accept 1/2-in.-dia.-shank bits. Bits with 1/2-in. shanks are more expensive but they will hold up to more stress and heat than the smaller 1/4-in. shank bits.
The best set-up for cutting molding with a router is to mount a router of at least 11/2 HP in a router table equipped with an adjustable fence. This way, you'll be able to focus your attention on feeding the wood into the bit without also having to manipulate the router over the wood. You can also mill much narrower stock on a router table.
A router table is a simple accessory consisting of a small tabletop with a router hanging inverted beneath it so the router bit can be raised and lowered through the table. Router tables have an adjustable fence that can be positioned closer to or further from the bit, depending on the cutting operation and the width of the wood being cut. The height of the bit, which will affect the shape that it cuts, can be raised or lowered. You can buy a router table from most home centers or woodworking supply catalogs, but many woodworkers prefer to build their own.
The process for cutting molding with a router table involves passing a strip of wood on-edge or on its face against the fence and past the spinning router bit to cut a profile. The settings you use for bit height and the distance from the fence to the bit depend on a number of factors: where the profile needs to be in relation to the edge of the board, how much wood you need to remove to make the shape, and the style of the cutter itself. For instance, a basemolding that has an ogee profile along the top edge and a pair of flutes near the bottom will require several bit and fence changes as well as three or more passes of the workpiece over the tool: at least one bit and fence setting to cut the ogee, a bit and fence change for cutting one flute, then a final fence position change for cutting the second flute. If you're cutting hardwood, it's a good idea to rout a profile in several passes, raising the bit each time in 1/8 to 1/4-in. increments to prevent the router from bogging down or making very ragged cuts.
Regardless of the kind of molding you're routing, start with clear, flat, straight boards. For best results, it's a good idea to run the edges of your workpieces over a jointer first to flatten them all along their length. Bowed or cupped edges will result in inconsistent routing. If you don't own a jointer, flatten the board edges by ripping them on a table saw with the rip fence aligned parallel with the blade.
Spend some time before you begin routing and think about the safest way to organize your cuts and router set-up. It's important to orchestrate the cutting so workpieces won't wobble or tip on the router table after the first pass. Rout the smallest details of the profile first, if possible, and save the larger curves or cut-out areas for last. For milling moldings narrower than about 11/2 in., the safest approach is to rout them on stock that's at least 4 to 6 in. wide, then rip-cut the molding free from the wider workpiece on a table saw. Rout both long edges of the board rather than just one, then cut each edge free to double your productivity. For milling short lengths of molding, always start with a workpiece that's long enough (at least 10 in.) to hold safely on the router table. Once you've cut the profile, cross-cut the molding to its required length. Never have more of the router bit exposed than is needed to make the cut.
The sequence of cuts you'll need to make to rout different moldings will vary with each type of molding you make. A few examples, and the steps required to make them, are shown in the photos at left.