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Eccentric Cutting Frame

Overview

Eccentric Cutting Frame
image courtesy Lindow Machine Works

The Eccentric Cutting Frame is a variation of the fly cutter, but the cutter's body is held in a Drill Spindle. The cutter is spinning along the same axis as the Drill Spindle, but eccentrically from it (like the eccentric chuck).

On the complexity scale, they fall into:
1. Eccentric Cutting Frame
2. Elliptical Cutting Frame
3. Rose Cutting Frame
4. Epicycloidal Cutting Frame

The eccentric cutting frame is used with a fly cutter which should be ground with a wide cutting angle. The typical fly cutter is ground with a 60° angle (see also, Sharpening a Rose Engine Fly Cutter, Round Rod). However, jewelers have shown that the angle needs to be >90° for the cut so that the light is reflected back to the viewer. Otherwise, it simply looks like a set of thick dark lines. 120° is not uncommon.

There is also a hand-operated version of this tool, which is called by some a Pearling Tool.

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Additional pictures of this device

Examples of work produced with this device

Eccentric Cutting on the end of a piece

Eccentric Cutting on the side of a piece (AKA, BarleyCorn)

Examples of this device in use

• This YouTube video shows the JaHo Ornamental Turning Device from Drechselbedarf. That device can be used on a traditional lathe to add ornamentation to work.

Usage Notes

1. Spacing of the cuts is something where planning is needed. It is commonly noted that the circles should touch, especially when the cuts are on the edge of a piece, or on a spherical surface. BarleyCorn is the term typically used for this, and Bill Ooms put together a spreadsheet for making the calculations. This and more are available on his web site.
2. Spacing of the cuts can also be used to give nice artistic effects. When they are close together, the artist can skip the making of a cut every so often (e.g., every 5th one) to give a nice effect. This is called an interrupted pattern, and is most commonly seen when cutting on the end of an object.
3. Balancing the eccentric cutting frame is very important, and this YouTube video shows Jon Spencer's design for that. (Jon Spencer is a great resource for cutting tools.)

More Information

Published Articles

• The Eccentric Cutter from James Lukin's Simple Decorative lathe Work, 1905. Ornamental Turners International Newsletter, Volume 25, No. 1 - Summer, 2018, pg. 8
• A High Speed Eccentric Cutter by Fred Armbruster.
  • Ornamental Turners International Newsletter, Volume 6, No. 2 - Fall, 1999, pg. 1
  • Ornamental Turners International Newsletter, Volume 20, No. 2 - Fall, 2013, pg. 18
• Lindow Rose Engine Alignment Procedures, Section 2, pg. 4 & pg. 8

Web Sites

• John Edwards' web site, OrnamentalTurning.co.uk, has really great information about the setup and use of these devices. There is a lot of great information on John's web site, and it is worth reading. Understanding the history behind the devices we use really helps make one far better at understanding and using today's rose engines. And, as I noted elsewhere on this site, the newer designs for devices like a spherical slide still draw much from what was done more than a hundred years ago. And this is why so many books that were written up to 200 years ago are referenced in the books section.