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What is a Mitre Joint?

A. Leverkuhn
A. Leverkuhn

A mitre joint is a joint made by cutting two pieces at angles. The result is a joint that fits together to form a specific angle. Woodworkers sometimes refer to these angled cuts as beveled cutting, and apply them as precisely as possible to provide better craftsmanship for a wide variety of home or commercial projects. Many involved in physical trades will be familiar with the basic physics of mitre joints for putting together superior products.

The most common mitre joints form 90° angles. Carpenters and others used mitre joints to create lots of different kinds of wooden constructions. Items like picture frames rely on mitre joints for tight rectangular design. Another very common use of mitre joints is in crown or base molding, where specific pieces of molding need to fit together for a tight pattern across an angled wall space.

Mitre joints give picture frames their rectangular shape.
Mitre joints give picture frames their rectangular shape.

Traditionally, mitre joints in woodworking have been made with a mitre saw. Manual mitre saws come in different forms including a “miter box saw”, where grooves in a rectangular design allow for guided manual sawing. Mitre table saws offer power sawing for mitre joints. Today is woodworking technology includes computer aided cutting machines that can make mitre joints and other specific woodworking tasks much more easily. Homeowners can buy various mitre joint design tools or kits to help with molding projects or similar installations.

In woodworking, a mitre saw is traditionally used to make precise mitre joints.
In woodworking, a mitre saw is traditionally used to make precise mitre joints.

Besides helping provide tight rectangular designs, mitre joints can also be used to create distinctive and unique patterns such as hexagons or other shapes. Using a mitre saw at various angles, skilled carpenters can create multi-sided inlays for custom floors, or other applications that provide a distinctive look for a property. Other mitre joint uses are practical: many items in a home, from stairs to drawers and doors, use mitre joints for solid design.

A mitre joint is used in crown molding.
A mitre joint is used in crown molding.

In addition to use in woodworking, mitre joints have other uses. Some plumbing configurations used mitre joint design to fit pipes, where getting a solid joint is essential to providing working installations. Mitre joints and other materials might provide for different commercial or consumer uses for plastic or metal products. Other types of home or commercial contractors use mitre joints for furnishing buildings. Carpeting and other flooring types rely on mitre joint designs to provide effective piece layouts. A general application of mitre joint design is often a part of what is taught in many industries where structuring physical materials is a significant part of the job.

Discussion Comments

anon980958

What are things it is used to make other than picture frames?

miriam98

@SkyWhisper - I’ve seen mitre joints in wood similar to what you have described, and in every case it was the work of an amateur. I think the seller most likely did it himself as you suggested.

If that had been the work of a carpenter, he should have been fired. Professional carpenters know how to get those miter joints just right.

It takes the right tools, the right measurements, and a good deal of patience. I’ll bet you anything he didn’t use a compound miter saw to cut those angles and just used a regular household saw.

SkyWhisperer

When I bought my house I made the mistake of not giving the property a second look around before going to closing. They say you should do that; just before closing, a week or so, inspect the property yourself to see if there’s anything you’ve missed the first time around.

Well, I didn’t do that. When I moved in, I looked up at the so-called crown molding in the dining room. It was obviously a do-it-yourself job. The thing that stood out like an eyesore was the miter joint. Apparently the seller didn’t cut the angles properly and there was a big gap where the joints were supposed to meet.

Additionally, most of the molding was sagging and had obviously been nailed down to keep it from sagging any further. It would have been better without the molding altogether. That’s what I get for not checking.

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    • Mitre joints give picture frames their rectangular shape.
      By: auremar
      Mitre joints give picture frames their rectangular shape.
    • In woodworking, a mitre saw is traditionally used to make precise mitre joints.
      By: Dmitry Naumov
      In woodworking, a mitre saw is traditionally used to make precise mitre joints.
    • A mitre joint is used in crown molding.
      By: pattie
      A mitre joint is used in crown molding.