Geometric Chuck
Overview
A Geometric Chuck (sometimes called an Epicycloidal Chuck) is used for cutting patterns made up of rolling centres.
Additional pictures of this device
Examples of this device in use
- This YouTube video from Chuck Bommarito (aka, outsidescrewball) shows a Leinhard Rose Geometric Chuck in use. The video is a bit long, but does show the chuck well, as well as a piece made on it.
- This YouTube video shows an Ibbetson Geometric Chuck on Holtzapffel rose engine lathe No. 1636.
How it works
Basically, it is achieved by rolling one object around another, forming a composite of two perfectly circular motions. The geometric mathematics behind this chuck's movement are explained by Dr. Frank Farris in his 1996 paper, "Wheels on Wheels on Wheels-Surprising Symmetry". There is also a nice article on this at Wolfram MathWorld.
Frank Dorion gave a lecture on the design and functions of a geometric chuck. He also built an oversized wooden model of one, helping to explain its function. This is one of the best overviews presented to date.
Notes on making one
A fella named Thomas posted instructions on Printables.com for 3D printing one.
A YouTube video about this piece in use is noted below.
More Information
Published Articles
- Designing 'Geo-Flowers' with a Geometric Chuck by Joshua Salesin. The Society of Ornamental Turners Bulletin 144, Spring, 2021, pg. 21
- Geometric Turning: The Manufacturer and Builder, by (unknown). Ornamental Turners International Newsletter, Volume 20, No. 1 - Spring, 2013, pg. 5
- Plant's Geometric Chuck, by (unknown). Ornamental Turners International Newsletter, Volume 25, No. 1 - Summer, 2018, pg. 19
- Plant's Geometric Chuck (parts I - IV), (1883). Published in “Amateur Mechanics”.
- Wheels on Wheels on Wheels - Surprising Symmetry (1986), by Frank A. Farris
- There is also an article about one in the "English Mechanic and Mirror of Science", Vol VII, No. 171 (03 July 1868).
Books and Papers
- A Brief Account of Ibbetson's Geometric Chuck Manufactured by Holtzapffel & Co. (1833), by John Holt Ibbetson, Esq.
- The Cycloid and All Forms of Cycloidal Curves and on the Use of such Curves in Dealing with the Motions of Planets, Comets, &c. and of Matter Projected from the Sun (1878), by Richard A Proctor.
- Holtzapffel Volume 6 (2013), by John Edwards. John captured quite a bit about these devices here. You can get from the The Society of Ornamental Turners.
- Index to the Geometric Chuck: A Treatise Upon the Description, in the Lathe, of Simple and Compound Epitrochoidal or “Geometric” Curves (1875), by Thomas Sebastian Bazely, M.A..
- Patterns for Turning comprising Elliptical and other figures Cut on the Lathe Without the Use of Any Ornamental Chuck (1872), by H. W. Elphinstone.
- Specimens in Eccentric Circular Turning with Practical Instructions for Producing Corresponding Pieces in the Art (1884), by John Holt Ibbetson.
Presentations
- Design and functions of a geometric chuck by Frank Dorion.
- Roy Lindley gave a demonstration to the club about geometric chuck patterns. The recording for this video is in the Ornamental Turners Int'l (OTI) member meeting videos, March 2023.
- 3D Printed Geometric Chuck (YouTube video) by PT.
Other
- (put spreadsheets here)
Disclaimer: eMail comments to me at OTBookOfKnowledge @ Gmail.com. The process of woodturning involves the use of tools, machinery and materials which could cause injury or be a health hazard unless proper precautions are taken, including the wearing of appropriate protective equipment. |