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The MultiMachine is all-purpose open source machine tool that can be built inexpensively by a semi-skilled mechanic with common hand tools, from discarded car and truck parts, using only commonly available hand tools and no electricity. Its size can range from being small enough to fit in a closet to one a hundred times that size. The MultiMachine can accurately perform all the functions of an entire machine shop by itself.

The MultiMachine was first developed as a personal project by Pat Delaney, then grew into a open source project organized via a Yahoo! group. The 2,600+ member support group that has grown up around its creation is made up of engineers, machinists, and experimenters who have proven that the machine works. As an open-source machine tool that can be built cheaply onsite, the MultiMachine could have many uses in developing countries. The MultiMachine group is currently focused on the humanitarian aspects of the MultiMachine, and on promulgating the concept of the MultiMachine as a means to create jobs and economic growth in developing countries.

The MultiMachine first became known to a wider audience as the result of the 2006 Open Source Gift Guide article on the Make Magazine website, in which the MultiMachine was mentioned under the caption "Multimachine - Open Source machine tool."

Uses of the MultiMachine

As a general-purpose machine tool that includes the functions of a milling machine, drill press, and metal lathe, the MultiMachine can be used for many projecs important for humanitarian and economic development in developing countries:

• Agriculture: Building and repairing irrigation pumps and farm implements
• Water supplies: Making and repairing water pumps and water-well drilling rigs.
• Food supplies: Building steel-rolling-and-bending machines for making fuel efficient cook stoves and other cooking equipment
• Transportation: Anything from making cart axles to rebuilding vehicle clutch, brake, and other parts.
• Education: Building simple pipe-and-bar-bending machines to make school furniture, providing "hands on" training on student-built MultiMachines that they take with them when they leave school.
• Job creation: A group of specialized but easily built MultiMachines can be combined to form a small, very low cost, metal working factory which could also serve as a trade school. Students could be taught a single skill on a specialized machine and be paid as a worker while learning other skills that they could take elsewhere.

MultiMachine accuracy

The design goals of the MultiMachine were to create an easily-built machine tool, made from "junk," that is nonetheless all-purpose and accurate enough for production work.

In almost every kind of machining operation, either the work piece or the cutting tool turns. If enough flexibility is built into the parts of a machine tool involved in these functions, the resulting machine can do almost every kind of machining operation that will physically fit on it. The MultiMachine starts with the concept of 3-in-1 machine tools -- basically a combination of metal lathe, mill and drill press -- but adds many other functions. It can be a 10-in-1 (or even more!) machine tool.

Six key construction techniques

At a high-level, the MultiMachine is built using vehicle engine blocks combined in a LEGO-like fashion. An almost no-cost version of the machine can be built by using engine blocks originally made with cylinder "sleeves" and then replacing bearings, adjusters and pulleys with parts cast from a very strong zinc/aluminum alloy that can be made from vehicle salvage.

The MultiMachine uses six unusual construction techniques to build five simple "modules" that bolt to a worn-out or broken vehicle or industrial engine block.

1. Engine blocks are the building blocks of the MultiMachine. Since cylinder bores are bored exactly parallel to each other and at exact right angles to the cylinder head surface, MultiMachine accuracy begins at the factory where the engine block was built.
2. In the most common version of the MultiMachine, one that has a roller bearing spindle, this precision is maintained during construction with simple cylinder re-boring of the #3 cylinder to the size of the roller bearing outside diameter (OD) and re-boring the #1 cylinder to fit the overarm OD. These cylinder-boring operations can be done in almost any engine shop and at low cost. An engine machine shop provides the most inexpensive and accurate machine work commonly done anywhere and guarantees that the spindle and overarm will be perfectly aligned and at an exact right angle to the face (head surface) of the main engine block that serves as the base of the machine.
3. Use a piece of pipe made to fit the inner diameter of the bearings as the spindle.
4. A three-bearing spindle is used because the "main" spindle bearings just "float" in the cylinder bore so that the third bearing is needed to "locate" the spindle, act as a thrust bearing, and support the heavy pulley.
5. The MultiMachine uses a unique way of clamping the engine blocks together that is easily built, easily adjusted, and very accurate.
6. The MultiMachine makes use of a concrete and steel construction technique that was heavily used in industry during the First World War and resurrected for this project.

The details of the MultiMachine construction are covered in an an 80-page document available at the Yahoo! group listed below. (This group also has plans for electric welders built from vehicle alternators, a design for an easily built hand-powered drill that is capable of cutting through the hardest steel and an easily cast metal alloy that is almost as strong as cast iron.)

Information used by permission of Pat Delaney, the founder of the MultiMachine project.

External links

• Make Magazine Open Source Gift Guide article

• Metalworking