A common approach for how to make cabinet doors is to use a matched pair of bits on the router table. In this class you’ll learn the process step by step. From information about the bits you need to set up to safe cutting, it’s all here.
You need to do all the work on a router table, not with a hand-held router. The cuts will be made using a two-piece match ground router bit set. One bit makes the end grain cuts, the other makes the long grain cuts. A shop-made sled will be used to handle the rails for the end grain cuts.
When making your doors do the end grain cuts first, then the long grain cuts. Once you’ve identified which bit is which use a felt tip and put a number 1 on the end grain cutter and a number 2 on the long grain cutter to remind you which bit to use first.
With your router unplugged, put the end grain cutter in your router in the router table. With a scrap piece of rail material in the sled approximate the height of the bit. Make sure the router bit won’t contact the base of your sled. The lowest portion of the end grain cutter should be about 1/8″ above the base of the sled.
Locate the fence by bridging the gap in the fence with a straight edge and allowing the straight edge to contact the ball bearing and the fence face. Lock the fence.
When you make your first test cut, cut into the rail material, but don’t cut into the sled.
After a test cut, check the relationship between the lip on the front of the rail and the shoulder on the back. The lip should be approximately half as big as the shoulder. Adjust the height of the bit accordingly. Raising the cutter makes the lip on the front thicker. Lowering the bit makes the shoulder on the back bigger.
Once the height is perfect it’s OK to cut into the sled. The sled becomes a set up gauge you can use the next time you set up the bits.
With the router unplugged, install cutter number 2 in the router table. Use one of your end grain cuts to set the height of the bit. Make the top of the tongue cutter on the bit even with the top of the tongue projecting from the end grain cut.
Set the fence location by making the face of the fence even with the ball bearing on the cutter. Lock the fence.
Add a feather board to your fence to hold the material tight to the table. Make a test cut. Use a push stick held horizontally to keep the material tight to the fence.
Check the height of the bit by dry assembling a joint. The front face of the end grain cut should be flush with the front face of the long grain cut. If it isn’t, adjust the height of the bit. If the end grain piece is too high you need to raise the long grain cutter. If the end grain cut is too low you need to lower the long grain cutter. If the difference between the two is tiny, less than the thickness of a piece of paper, you can leave it. The ledge will easily sand out after the door is assembled.
Before making any cuts mark the back faces of your door frame pieces. All the parts will be cut with the back side up, so you should be able to see your mark on the back throughout the cuts.
Make the end grain cuts on all your rails.
You can sometimes get chipping on the long grain cuts. You can reduce this significantly by making a zero clearance fence on your table. This only needs to be done on the infeed side of the fence. With the height of the bit and fence location set and the router running, slide the infeed fence into the spinning bit until it touches the ball bearing.
When the set up is right you’re ready to do the long grain cut on all four door parts. Make sure the back faces of the door parts are up on the pieces as you machine them. Once the long grain cuts are complete your door frame is ready for assembly.