What is a Mitered Cabinet Door and how are they made?

As I explained in the post “What is a Cope and Stick Cabinet Door and How are They Made?”, there are two major categories of Cabinet Doors. These are Solid Slab, or plank doors, and 5-piece doors.

The Slab door is simply several boards edge-glued and trimmed to the desired size.

5-piece cabinet doors are divided into two design categories; Cope and Stick and Mitered.

The 5-piece door is more complex but more reliable and more pleasing in appearance. This is especially true with Mitered doors which offer more moulding choices than Cope and Stick designs.

This post is focused on the Mitered, 5-piece cabinet door.

The drawing below shows a Cope and Stick Cabinet Door and Drawer Front on the left and a Mitered Cabinet Door and Drawer Front on the right. The differences are in the corners and the method of joining the parts of the frame.
The Mitered door has the frame joined at a 45-degree angle while the Cope and Stick door frame is connected at a 90-degree angle.

The five pieces in a Mitered door are the four parts of the frame, called Stiles and Rails. The Stiles are the vertical pieces, or sides of the frame and the Rails are the top and bottom pieces. The fifth piece of the 5-piece door is the panel, which the frame surrounds.

The reason the 5-piece door is more reliable than the Slab door is in the way each design responds to changes in relative humidity.

All woods will expand as humidity increases, and as humidity decreases they will contract. An average width Slab Cabinet Door, being between 14 and 20 inches wide, will expand and contract with humidity cycles over the year by as much as three-sixteenths-inches. Some wood types react more and some less, but three-sixteenths-inches is typical for a Slab door.

While this may not sound like much, it is enough to prevent butt-door pairs from closing during high humidity times and cause a gap between the butt doors of one-half inch in low humidity times.

Here is where the 5-piece design comes to the rescue.

In the 5-piece door the panel is allowed to float within the frame, so during panel expansion the panel edges simply move deeper into the Stiles and during contraction the panel slightly pulls back. The Mitered door is designed with a groove for in the stiles so panel movement is accepted without being noticed.

The top drawing shows an end-view of the stile with a contracted wood (low humidity) panel, while the drawing below shows a humidity-expanded panel. Notice that the panel still reacts dimensionally with changes in humidity but in the 5-piece door this panel movement is absorbed by the groove in the stiles. This design keeps the overall width of the door constant as the relative humidity fluctuates.

With Mitered doors there are several joining methods used across the industry. The newer methods using computerized machinery are more reliable and far more accurate. The blind mortise and tenon method produces an invisible joint that is both stronger and more resistant moisture than earlier joining methods. An example of this blind joint is pictured below.

Mitered Cabinet Door Joint

 

Blind Mortise and Tenon Mitered Cabinet Door Joint 

 

Shop For: Mitered Cabinet Doors

What is a Cope and Stick Cabinet Door, and how are they made?

Generally speaking there are two major categories of Cabinet Doors.  These are Solid Slab (or plank doors) and 5-piece doors.

The Slab door is simply several boards edge-glued and trimmed to the desired size.

The 5-piece door is more complex but more reliable and more pleasing in appearance.

5-piece cabinet doors are divided into two design categories; Cope and Stick and Mitered.

This post covers the Cope and Stick, 5-piece cabinet door.

Cope & Stick 5 Piece Cabinet Doors

The five pieces in a Cope and Stick door are the four parts of the frame, called Stiles and Rails. The Stiles are the vertical pieces, or sides of the frame and the Rails are the top and bottom pieces. The fifth piece of the 5-piece door is the panel, which the frame surrounds.

The reason the 5-piece door is more reliable than the Slab door is in the way each design responds to changes in relative humidity.

All woods will expand as humidity increases, and as humidity decreases they will contract. An average width Slab Cabinet Door, being between 14 and 20 inches wide, will expand and contract as humidity cycles over the year by as much as three-sixteenths-inches. Some wood types react more and some less, but three-sixteenths-inches is typical for a Slab door.

While this may not sound like much, it is enough to prevent butt-door pairs from closing during high humidity times.

Here is where the 5-piece design comes to the rescue.

In the 5-piece door the panel is allowed to float within the frame, so during panel expansion the panel edges simply move deeper into the Stiles and during contraction the panel slightly pulls back. The Cope and Stick door is designed with a groove for in the stiles so panel movement is accepted without being noticed.

panel float space

panel float space

The top drawing shows an end-view of the stile with a contracted wood (low humidity) panel, while the drawing below shows a humidity-expanded panel. Notice that the panel still reacts dimensionally with changes in humidity but in the 5-piece door this panel movement is absorbed by the groove in the stiles. This design keeps the overall width of the door constant as the relative humidity fluctuates.

Cope and Stick doors differ from the other 5-piece design by the method of joining the frame. This drawing shows the difference between the Mitered joint and the Cope and Stick joint. See the post on What is a Mitered Cabinet Door for more info.

Shop Cope & Stick Cabinet Doors At The Door Stop

Cope and Stick cabinet doors can be priced and ordered online from CabinetDoors.com and Mitered cabinet doors here.

How to prevent damage to unfinished cabinet doors prior to finishing

All unfinished wood products are completely unprotected from damage caused by warping of the wood and splitting from the end-grain.

This warping and splitting is very likely to occur with swings in relative humidity or temperature on any unfinished wood products.

Here are a few tips on how to minimize or prevent these problems when the wood products cannot be properly finished upon delivery.

As soon as possible after delivery, place your new cabinet doors in a temperature controlled space away from direct sunlight.

Make sure that air can circulate all around each door. If the doors are stacked one on top of the other, air will only circulate over the exposed surface of the top door which will allow moisture gain or loss only from that exposed surface. This will cause a moisture mismatch between the face and back of that door, and cause it to warp. If the humidity change is large, end-grain cracking is also likely to occur.

It’s best to avoid stacking the unfinished doors and instead, stand them up and lean them against another surface allowing air to circulate freely around the front and back of each door. This will allow the same level of humidity on both front and back of each door and warping will be prevented.

These precautions will minimize warping problems for a few days but for longer term protection proper sealing and finishing will be necessary.

Some cabinet door finishing tips are available at the CabinetDoors.Com blog.

Cabinetdoors.com is oldest and largest manufacturer of cabinet doors online with over 35 years of experience shipping all across America.