Planer (metalworking)
A single-point cutting tool moves across a stationary workpiece to remove metal. This linear relative motion is the core function of every planer. The machine cuts while the table holds the object still or moves it back and forth. A typical planer removes a tremendous amount of material in one pass with high accuracy. It generates accurate flat surfaces even if grinding offers greater precision later. Operators use these tools to cut slots like keyways into large blocks of steel.
Workers generate flat surfaces by moving the table along a straight path. They also cut internal features starting from a drilled or cored hole. A boring-bar type tool allows for irregularly shaped holes with tight corners that milling cannot handle. Some shops couple the table's linear motion to simultaneous rotation for helical cutting. This process resembles both helical milling and single-point screw cutting. Such operations remain possible despite the dominance of wire EDM technology today.
Smaller tool and die shops maintain and repair large stamping dies using these machines. Plastic injection molds also receive attention from operators who prefer older equipment. An abnormally large block of metal measuring 4 feet by 8 feet or more requires squaring when floor mills are unavailable. These massive horizontal grinders often cost too much or prove impractical for specific tasks. An old machine already paid for holds substantial cost advantage over any new purchase. The gradual obsolescence of such techniques explains why they persist in industrial contexts longer than consumer fashions drop off.
Double-housing varieties feature vertical supports on both sides of their long bed. Open-side designs have a vertical support on only one side allowing workpieces to extend beyond the bed. Metal planers vary in size from a table dimension of 30 inches by 72 inches up to 20 feet by 62 feet. Their weight ranges from around 20,000 pounds to over 1,000,000 pounds. This sheer mass distinguishes them from smaller shapers that use stationary cutting tools.
Early planing ideas were underway in France during the 1750s. James Fox and Richard Roberts developed the machine into what we call a modern tool in British shops during the late 1810s. George Rennie, Matthew Murray, and Joseph Clement also contributed to this evolution. The exact details remain contentious because development work was undocumented for various reasons. Proprietary secrecy prevented records from being kept while no one took down notes for posterity. Roe published a short chapter in 1916 describing the story as thoroughly as he could discover it.
Common questions
What is the core function of a planer in metalworking?
A single-point cutting tool moves across a stationary workpiece to remove metal. This linear relative motion is the core function of every planer.
When did James Fox and Richard Roberts develop the modern planer machine?
James Fox and Richard Roberts developed the machine into what we call a modern tool in British shops during the late 1810s. George Rennie, Matthew Murray, and Joseph Clement also contributed to this evolution.
How large can a metal planer table dimension be compared to its weight?
Metal planers vary in size from a table dimension of 30 inches by 72 inches up to 20 feet by 62 feet. Their weight ranges from around 20,000 pounds to over 1,000,000 pounds.
Why do some shops still use older planing machines instead of new technology?
An old machine already paid for holds substantial cost advantage over any new purchase. These massive horizontal grinders often cost too much or prove impractical for specific tasks.
What distinguishes double-housing planers from open-side designs?
Double-housing varieties feature vertical supports on both sides of their long bed. Open-side designs have a vertical support on only one side allowing workpieces to extend beyond the bed.