Drilling Boring Reaming and Tapping

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Drilling Boring Reaming and Tapping Powered By Docstoc
					Drilling, Boring,
Reaming, and
Tapping

Session 11



                    1
2
To Spot and Drill
Work in a Chuck
• Spotting ensures drill will start in
  center of work
• Spotting tool used to make shallow, V-
  shaped hole in center of work
  • Provides start for drill to follow
• Most cases hole spotted quickly using
  center drill
  • Extreme accuracy use spotting/
    chamfering toolbit
                                           3
Spotting Work in a Chuck
1. Mount work true in chuck
2. Set lathe to proper speed for type of
   material
3. Check tailstock and make sure in line
4. Spot hole with center drill or spotting
   tool


                                             4
Drilling Work in a Chuck
1. Mount twist drill in tailstock spindle,
   drill chuck, or drill holder
2. Start lathe and set for proper RPM for
   workpiece and cutting tool
3. With tailstock spindle handle, move
   drill tip to end of part. Note reading on
   tailstock spindle.
4. Drill to desired depth, applying cutting
   fluid frequently
                                               5
Spotting Work in a Chuck
5. To gage depth of hole, use
   graduations on tailstock spindle, or
   measure depth with steel rule
6. Withdraw drill frequently to break
   and/or remove chips and measure
   depth of hole
7. If hole is through, always ease force
   on feed as drill breaks through work


                                           6
Boring
• Operation of enlarging and truing drilled
  or cored hole with single-point cutting
  tool
• For producing special-diameter holes
• May be drilled in lathe, but not accurate
  • Drill become dull or hit hard spot and
    wander
  • Reamer will follow drilled hole and be off
• For reamed hole to be straight and true
  • Drill, bore and then ream
                                                 7
To Bore Work in a Chuck
1. Mount work in chuck; face, spot, and
   drill hole approximately .060 in
   undersize
2. Select boring bar as large as possible
   and have it extend beyond holder only
   enough to clear depth of hole to be
   bored
3. Mount boring bar holder in toolpost on
   left-hand side of compound rest
                                            8
Boring Work in a Chuck
4. Set boring toolbit on center
5. Set lathe to proper speed and select
   medium feed
6. Start lathe and bring boring tool into
   contact with inside diameter of hole
7. Take light trial cut .250 inch long at
   right-hand end of work
8. Stop lathe and measure hole diameter
   with telescopic gage or inside
   micrometer
                                            9
Boring Work in a Chuck
9. Determine amount of material to be
   removed from hole
  •   0.10 to 0.20 in. for a finish cut
10.Set depth of cut for half amount of
   metal to be removed
11.Start lathe and take roughing cut
  •   Slow lathe speed and increase feed if
      chatter

                                              10
Boring Work in a Chuck
12.Stop lathe and bring boring tool out of
   hole without moving crossfeed handle
13.Set depth of finish cut and bore hole to
   size
  •   Fine feed recommended for good surface
      finish
13.Check hole diameter

                                               11
Reaming
•   Quickly obtain accurately sized hole
    and produce good surface finish
•   May be performed after hole drilled
    and bored




                                           12
Reaming Work on a Lathe
1. Mount work in chuck; face, spot, and drill
   hole to size
  •   Holes under .500 in – drill .015 in. undersize
  •   Holes over .500 in. – drill .030 in. undersize
  •   Holes true – bored .010 in. undersize
2. Mount reamer in drill chuck or drill holder
  •   Holes .625 in and larger, fasten lathe dog
      near reamer shank and support tail

                                                   13
Reaming Work on a Lathe
3. Set lathe to approximately half drilling
   speed
4. Bring reamer close to hole and lock
   tailstock in position
5. Start lathe, apply cutting fluid to
   reamer and slowly geed it into drilled
   or bored hole with tailstock handwheel


                                              14
Reaming Work on a Lathe
6. Occasionally remove reamer from hole
   to clear chips from flutes and apply
   cutting fluid
7. Once hole reamed, stop lathe and
   remove reamer from hole

•   Caution: Never turn lathe spindle or
    reamer backward for any reason.
    This will damage reamer!
                                       15
Tapping
• One method of producing an internal
  thread on a lathe
• Tap aligned by placing point of lathe
  dead center in chuck end of tap to
  guide while tap turned by tap wrench
• When tapping hole in lathe, lock
  spindle and turn tap by hand


                                          16
To Tap a Hole in a Lathe
1. Mount work in chuck; face and center
   drill
2. Select proper tap drill for tap to be used
3. Set lathe to proper speed
4. Drill with tap drill to required depth
  •   Use cutting fluid if required
5. Chamfer edge of hole slightly larger
   than tap diameter
                                            17
To Tap a Hole in a Lathe
6. Stop lathe and lock spindle, or put
   lathe in its lowest speed
7. Place taper tap in hole and support
   shank with tailstock center
8. With suitable wrench, turn tap,
   keeping dead center snug into
   shank of tap by turning tailstock
   handwheel


                                         18
To Tap a Hole in a Lathe
9. Apply cutting fluid while tapping
   hole
10.Back off tap frequently to break the
   chip
11.Remove taper tap and finish tapping
   hole with plug or bottoming tap




                                          19
Grinding on a Lathe
• May do cylindrical and internal grinding
  • Toolpost mounted on lathe used for
    cylindrical and taper grinding
  • Internal attachment permits grinding of
    straight and tapered holes
• Should be done on lathe only when no
  other machine available
• Work rotates in opposite direction to
  grinding wheel so lathe must be
  equipped with reversing switch
                                              20
Grinding a Lathe Center
1. Remove chuck or driveplate from spindle
2. Mount lathe center in headstock spindle
3. Set slow spindle speed
4. Swing compound rest to 30º with
   centerline
5. Protect ways of lathe with cloth or
   canvas and place pan of water below
   lathe center
                                       21
Grinding a Lathe Center
6. Mount toolpost grinder and adjust center
   of grinding spindle to center height
7. Mount proper grinding wheel; true and
   dress
8. Start lathe, with spindle revolving in
   reverse
9. Start grinder and adjust grinding wheel
   until it sparks lightly against revolving
   center
                                          22
Grinding a Lathe Center
10.Lock carriage in this position
11.Feed grinding wheel in .001 in. using
   crossfeed handle
12.Move grinder along face of center
   using compound rest feed at a steady
   pace



                                           23
Grinding a Lathe Center
11.Check angle of center using center
   gage, and adjust compound rest if
   necessary
12.Finish-grind center
  •   Polish center with abrasive cloth at high
      spindle speed if high finish desired




                                                  24

				
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posted:3/12/2011
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