Design for Manufacturing: Bar Stock Diameter and Standard Tooling

This article examines the risks associated with special bar stock to reduce waste.

Metal is often formed into long, rounded bars known as "bar stock." It may be either hollow or solid. Bar stock is produced in bulk by smelting yards. Bar stock is often used in large-scale industrial operations such as reinforcing concrete as rebar.

Machinists may make use of bar stock to create machined parts. Design engineers should make every attempt possible to ensure that machined parts are selected to allow for the use of standard-sized bar stock that will require a minimal amount of machining. By selecting bar stock of the same radius as the end product, machining operations are reduced. By selecting bar stock in a standard size, specialized tooling is minimized. These actions will drive overall processing and material costs down.

If

(a) Designing machined parts and using extruded bar stock

Then

(a) Avoid the use of custom-sized bar stock.
(b) Use the thinnest possible bar stock for the application at hand.
(c) Use standard sized bar stock whenever possible to avoid the need for specialized tooling.
(d) Use hollow bar stock when necessary to reduce machining costs.
(e) Use the appropriate shape of bar stock to minimize machining costs.

Keeping to these thumbrules will minimize special tooling costs, processing costs, and allow for less storeroom space to be wasted on special inventory.