Drilling Flashcards
type of drill press for precise work up to 1/2”, has no power feed and driven by a v-belt
sensitive drill press
drill press with power feed and for drilling holes from 1/2”-4”
upright drill press
electric hand drills are capable of drilling holes up to
1/2” in diameter
larger hand drills are sized by the chuck from
1/2-3/4
what are 2 ways to size a drill press
largest diameter a workpiece can be centered
distance from column to tool
difference of a drill sleeve and drill socket
sleeves increase diameter of a taper
sockets reduce taper
difference between drill jig and fixtures
fixtures hold and jigs guide tool
drill bit angle for general purpose
118
drill bit angle for soft material
60-90
drill bit angle for hard material
150
drilling too fast will
premature tool wear
drilling too slow will
break tool
cause of drill chatter
pilot hole too large
cause of bell mouth hole
cutting lips uneven length
point angle uneven
the diameter of a drill is measured across the
margins
lip clearance is achieved by
grinding the heel lower than the cutting edge
drill 35-40 degrees used for deep holes in soft material, like aluminum, copper, and zinc as these materials jam flutes in normal drill
high helix drills
drill used to enlarge existing holes, have 3 or 4 flutes and cannot cut their centre
core drills
drill having one or two holes that run the length of the drill and exit behind the cutting edge
oil hole drills
drill used in soft material such as brass, bronze and plastics
straight flute drills
most countersink have an angle of
82 degrees
spiral flute taps push chips
up out of the hole
spiral point (gun) tap push chips
down out of the hole
straight fluted tap chips
jam holes
