Boring Bar

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Related to Boring Bar: Boring Head

boring bar

[′bȯr·iŋ ‚bär]
(mechanical engineering)
A rigid tool holder used to machine internal surfaces.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Boring Bar


a device for boring holes; it is in the form of a cylindrical spindle with radially placed holes, either rectangular or round, in which individual or block cutters are fastened. Boring bars usually have a shaft that is fastened to the spindle of a boring machine. If the bar is long, the opposite end is held and guided by a sleeve on an end support. If the workpiece is fastened to a fixture rather than to the machine itself, the boring bar is directed by jig bushings, and the connection of the boring bar to the spindle is made with a coupling permitting self-alignment of boring-bar axis.

Various boring bars are designed to permit radial feed of the cutters for adjustment—that is, for compensation of the dimensional wear of the cutters—or the machining of indentations and grooves. Boring bars may be equipped with vibration dampers to reduce the level of vibrations arising in the cutting process.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
For example, a desire of being able to perform a cutting operation into pre-drilled holes in a workpiece limits the diameter or cross-sectional size of the boring bar during boring when the vibrations are a cumbersome part of the manufacturing process [9].
* Boring bars: use and application for both lathes and mills.
and I feed the boring bar back out of the gun barrel
A tool changer sits below the spindle for switching boring bar assemblies.
Even so, some amount of downtime will occur anyway, particularly where line boring bar supports are concerned, in a typical parts-punishing, high-production application such as engine block boring, trips to the tool room for repair and replacement are unavoidable and may be required several times per month.
Instead of using the 1.5" boring bar, he suggested turning a drill 180 degrees and using it as a boring bar.
For example, rather than employing a special line boring tool--which is both expensive and requires development and delivery time--they were able to do the required machining with a standard boring bar.
Using a carbide-inserted boring bar, I took the spade-drilled holes up, and increased the surface quality and size.