Holemaking on the Mill 230

Manual Machining Training

Class Information

Tooling U classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and typically requires at least two hours of instruction time.

Class Name:	Holemaking on the Mill 230
Description:	This class describes how to perform common holemaking operations on the manual mill and explains common principles about each holemaking process.
Prerequisites:	150200 150220
Difficulty:	Intermediate
Number of Lessons:	15

Below are all the competencies and job programs that contain the class Holemaking on the Mill 230. Job programs are our traditional class lists organized according to common job functions. Competences are our latest job-specific curricula that help tie online learning to practical, hands-on tasks.

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Competencies
Maintenance Machinist Maintenance Mechanic Manual Mill Operator

Job Programs
Job: Machinist/Machine Setter Job: Machinist: Tool Room Job: NIMS

Class Outline
Objectives Overview of Holemaking Operations Drilling Principles Tapping Principles Tapping: An Example Counterboring Principles Counterboring: An Example Countersinking Principles Countersinking: An Example Reaming Principles Reaming: Pre-Drilling the Hole Reaming: An Example Boring Principles Boring: An Example Summary

Class Objectives

Describe common holemaking operations performed on the mill.
Describe common principles for drilling.
Describe common principles for tapping.
Describe the steps necessary for tapping a hole.
Describe common principles for counterboring.
Describe the steps necessary for counterboring a hole.
Describe common principles for countersinking.
Describe the steps necessary for countersinking a hole.
Describe common principles for reaming.
Describe the steps necessary for pre-drilling a reamed hole.
Describe the steps necessary for reaming a hole.
Describe common principles for boring.
Describe the steps necessary for boring a hole.

Class Vocabulary
adjustable boring head		A type of toolholder that holds the boring tool and is capable of being adjusted to different hole diameters.
blind hole		A drilled hole that begins on one side of the workpiece and terminates inside the workpiece.
bore gage		A hole inspection gage that makes three points of contact within the hole. Bore gages are handheld, variable instruments that provide very accurate readings of hole sizes.
boring		The process of enlarging an existing hole with a single-point tool.
boring tool		A long bar used to position a single-point tool for boring operations.
center drill		A type of drill with a wide shank and a 60 degree angle tip. The center drill is used to start a hole before drilling to ensure that the hole is machined on centerline.
chamfer tool		A tool that creates a beveled surface that eliminates a 90° sharp corner on the cutting edge.
collet		A split-sleeve device that when expanded or contracted grips a cutting tool in place on the mill.
concentric		Having a common center or sharing the same axis with another object.
counterboring		An operation that enlarges the end of a predrilled hole to allow room for a head of a screw or nut.
countersinking		The cutting of a beveled edge at the end of a hole so that the head of a screw can rest flush with the workpiece surface.
deflecting		Deviating from a straight line or plane when a force is applied.
depth adjustment nut		A nut located on a threaded rod that is numbered in thousandths of an inch to determine spindle depth.
dowel pin		A type of fastener that is inserted into holes in two adjacent workpieces to hold them together. Dowel pins are fitted tightly into holes to prevent motion or slipping.
drill bushing		A hardened steel tube used to guide cutting tools such as drills and reamers.
drill chuck		A type of toolholder that holds drill bits on the mill. Drill chucks allow for quick installation and removal of drill bits for various drilling operations.
drilling		The process of using a multi-point tool to penetrate the surface of a workpiece and make a round hole.
edge finder		A device used on a mill to locate the exact position of a part edge along the X-axis or Y-axis.
end milling		A milling operation that uses a narrower mill to create slots, pockets, and contours in a workpiece.
face milling		A milling operation that produces a flat surface by guiding a wider mill across the surface of the workpiece.
hand tap		The manual tap used in a hand tapping operation.
major diameter		On a thread, the diameter from crest to crest of an external thread or the diameter from root to root of an internal thread.
milling machine		A machine that uses a multi-point tool to remove metal from the surface of a workpiece.
pilot		The truncated end of the counterboring tool that helps guide the cutter straight into the hole.
pin gage		A hardened, cylindrical gage used to inspect the size of a hole. Pin gages are available in standard diameters.
pitch		The distance between a point on an individual thread to the corresponding point on the next thread.
pitch diameter		The diameter of the part measured from the point at which the width of the groove and the width of the thread are equal.
reamer		A multi-point cutting tool with straight cutting edges used to enlarge or smooth holes that have been previously drilled.
reaming		The process of using a multi-point tool to smooth the interior surface of a hole.
tap		A cylindrically shaped, threaded device that either cuts or presses threads into a pre-drilled hole.
tap drill size		The size of the drill required for a given threaded hole. The hole is drilled to this size before it is tapped.
tapping		The process of cutting internal threads in a round hole with a multi-point tool.
telescope gage		A measuring instrument with a spring-loaded device used to check the inner diameter of a part. Telescope gages are then measured with a micrometer to get the proper value.
thread gage		A measuring instrument used to inspect the internal threads of a part.
thru hole		A drilled hole that begins on one side of the workpiece and extends through and exits another surface of the workpiece.