Thursday , February 22 2018
Home > Lathe Projects > Plans for an Improved 6″ Craftsman-Style Circle Cutter

Plans for an Improved 6″ Craftsman-Style Circle Cutter

by Glenn W.

Material: Steel

Units: (in)

This Craftsman-style circle cutter is designed to be used in a standard Drill Press or Vertical Milling Machine only.

It is designed for cutting 1″ to 6″ diameter holes in sheet metal, brass, copper, plastic, wood, or other composite materials. You can also cut 1″ to 6″ diameter circular disks or wheels. This tool is only recommended for material thicknesses of 1/8″ or less.

Some examples of practical uses for this tool are:

  • Cutting holes in automotive dash panels to fit around gauges.
  • Cutting holes in sheet metal where hoses will pass through
  • Cutting wheels for toys.
  • Cutting round discs in aluminum for making fly-fishing reels.
  • Practical uses are endless …

This tool is fully adjustable for cutting diameters from as small as approximately 1″ to as large as approximately 6″.

By simply grinding the proper angles and reliefs on standard 1/4″ HSS tool bits you can cut perfect holes or round discs, depending on the orientation of the tool bit cutting edge.

The attached set of drawings and assembly plans are based on a Sears Craftsman tool, model #25293 (pictured above). However, the design, dimensions, and components have been modified for improved performance and safety.

Proper cutting speeds, cutter relief angles, etc. will need to be established and adjusted according to the job at hand and the material being cut.

Important Notes:

  • Speed of drill press or milling machine should NOT exceed 500 RPM when using this cutter.
  • Always wear safety glasses when using this tool.
  • Use of cutting oil or coolant will greatly improve cutter performance when cutting metals.
  • Not recommended for materials thicker than 1/8″.
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About Tyler

Tyler is a hobby machinist and 3D printing aficionado. He teaches computer programming and web development at Highline College near Seattle. Tyler founded Projects In Metal in 2008 because he was frustrated by the lack of free plans available for hobby machinists.

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5 comments

  1. Nice plans Tyler.  Looks stout and rigid.  Would you believe I still have my original Craftsman circle cutter that I bought with my Craftsman floor model drill press (bought in 1988)?  The Craftsman circl cutter is somewhat delicate, very limited to cutting thin, soft materials but still a useful tool.

    Regards, Al

  2. Thanks Al, but they are actually Glenn's plans. He did all the work, I just posted the project to the site for him.

  3. This tool is technically called a trepanning tool. A reversible cutter bit allows for making a smooth hole and discarding the disc or a smooth edged disc and discardint the parent material.

    SPI makes a much better designed tool and supplies a precise ruler to measure the intended hole or disc. I made a set of ink platens for a printing press out of 1/4″ steel with mine; it took a long time to accomplish safely and left a #7 hole in the center of the platens, but they worked for many years.

  4. That is a really nice piece and looks way stronger than my Crapsman.  I've primarily used them for wood and plastic, but never for metal.

  5. Donno about all the comments about the sears one being weak… I've had one for years and have used it hundreds of times to cut out circles in MDF and even hardwood.  I use it the most for speaker enclosure cutouts for speakers needing holes smaller than 6″, almost always in materials 5/8-3/4″ thick.  I've also used it a number of times as a boring head in aluminum castings with the drill press before I owned a real one and a mill, and even cut a bunch of things using a brazed carbide lathe bit.