Drilling Test
The reamer should be driven about _______ the RPM of your drilling speed
1/2
Included angle of the lips on a general twist drill is
118 degrees
Countersinks are commonly found with included angles of
60,82,90 and 100 degrees.
What is a blind hole
A hole that is not drilled all the way through the work piece.
What is a pilot hole
A smaller hole drilled before the larger hole is then drilled
Feed
Advancement of the cutting tool into a workpiece
Name three functions of the flutes on a twist drill.
Create the cutting lips. Provide a pathway for chips to flow out of the hole during drilling operations and for cutting fluid to flow into the hole to help cool and lubricate the cutting lips.
What is drilling?
Drilling i s the process of using a cylindrical rotating cutting tool that is sharpened on its end to create a hole.
Twist drill bits have spiral grooves in their sides called...
Flutes
Materials used to make hole making cutting tools:
HSS, Tungsten Carbide
Explain the purpose of a counterbore.
It allows a screw head or nut to be positioned flush with or below the surface of the workpiece surface.
Twist Drill bits are sized according to diameter by four methods...
Letter, Wire gage or Number drill, Fractional drill, Metric Drill
What should be done as a drill nears the "breakthrough" point during drilling?
Lighten up on the pressure to prevent grabbing.
What is the largest diameter of a thread?
Major diameter
Parts to a twist drill
Shank,Body, Drill Point
What is general-purpose hand drillinh usually done with?
Twist Drills
What are two reasons why a hole may need to be countersunk?
When a chamfer is needed or a flathead screw must be installed.
What factors might determine when a hole must be finished by reaming?
When a smooth finish and precise size are needed.
A thread is
a spiral groove made on a round external or internal diameter
Countersinking with an 82 degree countersink bit will accommodate...
a standard flathead screw.
Countersinking is also peformed to create a...
chamfer at the opening of a hole.
Upright drill press consists of a
column mounted at 90 degrees to a base.
An external thread is cut with a
die
A hole slightly smaller than the desired size must first be...
drilled
Counterboring...
increases the diamter of a hole to a certain depth in order to allow a screwhead or nut to be positioned flush with or below the workpiece surface.
Countersinking
is the process of cutting a tapered opening holr so that a flathead screw can be installed flush with the workpiece surface.
Reaming
is the process of finsihing a hole to precise size with a smooth finished surface.
Spotfacing
is the process of machining a flat spot on a rough surface surrounding a hole opening so that bolts, nuts, and washers will be properly seated when tightened.
(Reaming) For a hole up to 1/4"...
should be produced undersize by 0.010"
(Reaming) for a hole between 1/4" and 1/2"...
should be produced undersize by 0.015"
(Reaming) for a hole between 1/2" and 1-1/2"...
should be produced undersize by 0.025
Two types of starter drill bits are the
spot drill and center drill
List two types of drill shanks
straight and tapered.
__________ shank drills are used with a chuck.
straight.
An internal thread is cut with a
tap
__________ shank drills fit directly into the drill press spindle
tapered.
V-Blocks are used
to securely hold round workpieces while performing drilling or reaming
Before beginning to drill a hole, its recommended to center punch the part so the drill does not...
walk
