Drilling, Boring, Reaming, and Tapping Session 11

To Spot and Drill Work in a ChuckSpotting ensures drill will start in center of workSpotting tool used to make shallow, V-shaped hole in center of workProvides start for drill to followMost cases hole spotted quickly using center drillExtreme accuracy use spotting/ chamfering toolbit

Spotting Work in a ChuckMount work true in chuckSet lathe to proper speed for type of materialCheck tailstock and make sure in lineSpot hole with center drill or spotting tool

Drilling Work in a ChuckMount twist drill in tailstock spindle, drill chuck, or drill holderStart lathe and set for proper RPM for workpiece and cutting toolWith tailstock spindle handle, move drill tip to end of part. Note reading on tailstock spindle.Drill to desired depth, applying cutting fluid frequently

Spotting Work in a ChuckTo gage depth of hole, use graduations on tailstock spindle, or measure depth with steel ruleWithdraw drill frequently to break and/or remove chips and measure depth of holeIf hole is through, always ease force on feed as drill breaks through work

BoringOperation of enlarging and truing drilled or cored hole with single-point cutting toolFor producing special-diameter holesMay be drilled in lathe, but not accurateDrill become dull or hit hard spot and wanderReamer will follow drilled hole and be offFor reamed hole to be straight and trueDrill, bore and then ream

To Bore Work in a ChuckMount work in chuck; face, spot, and drill hole approximately .060 in undersizeSelect boring bar as large as possible and have it extend beyond holder only enough to clear depth of hole to be boredMount boring bar holder in toolpost on left-hand side of compound rest

Boring Work in a ChuckSet boring toolbit on centerSet lathe to proper speed and select medium feedStart lathe and bring boring tool into contact with inside diameter of holeTake light trial cut .250 inch long at right-hand end of workStop lathe and measure hole diameter with telescopic gage or inside micrometer

Boring Work in a ChuckDetermine amount of material to be removed from hole0.10 to 0.20 in. for a finish cutSet depth of cut for half amount of metal to be removedStart lathe and take roughing cutSlow lathe speed and increase feed if chatter

Boring Work in a ChuckStop lathe and bring boring tool out of hole without moving crossfeed handleSet depth of finish cut and bore hole to sizeFine feed recommended for good surface finishCheck hole diameter

ReamingQuickly obtain accurately sized hole and produce good surface finishMay be performed after hole drilled and bored

Reaming Work on a LatheMount work in chuck; face, spot, and drill hole to sizeHoles under .500 in drill .015 in. undersizeHoles over .500 in. drill .030 in. undersizeHoles true bored .010 in. undersizeMount reamer in drill chuck or drill holderHoles .625 in and larger, fasten lathe dog near reamer shank and support tail

Reaming Work on a LatheSet lathe to approximately half drilling speedBring reamer close to hole and lock tailstock in positionStart lathe, apply cutting fluid to reamer and slowly geed it into drilled or bored hole with tailstock handwheel

Reaming Work on a LatheOccasionally remove reamer from hole to clear chips from flutes and apply cutting fluidOnce hole reamed, stop lathe and remove reamer from hole

Caution: Never turn lathe spindle or reamer backward for any reason. This will damage reamer!

TappingOne method of producing an internal thread on a latheTap aligned by placing point of lathe dead center in chuck end of tap to guide while tap turned by tap wrenchWhen tapping hole in lathe, lock spindle and turn tap by hand

To Tap a Hole in a LatheMount work in chuck; face and center drillSelect proper tap drill for tap to be usedSet lathe to proper speedDrill with tap drill to required depthUse cutting fluid if requiredChamfer edge of hole slightly larger than tap diameter

To Tap a Hole in a LatheStop lathe and lock spindle, or put lathe in its lowest speedPlace taper tap in hole and support shank with tailstock centerWith suitable wrench, turn tap, keeping dead center snug into shank of tap by turning tailstock handwheel

To Tap a Hole in a LatheApply cutting fluid while tapping holeBack off tap frequently to break the chipRemove taper tap and finish tapping hole with plug or bottoming tap

Grinding on a LatheMay do cylindrical and internal grindingToolpost mounted on lathe used for cylindrical and taper grindingInternal attachment permits grinding of straight and tapered holesShould be done on lathe only when no other machine availableWork rotates in opposite direction to grinding wheel so lathe must be equipped with reversing switch

Grinding a Lathe CenterRemove chuck or driveplate from spindleMount lathe center in headstock spindleSet slow spindle speedSwing compound rest to 30 with centerlineProtect ways of lathe with cloth or canvas and place pan of water below lathe center

Grinding a Lathe CenterMount toolpost grinder and adjust center of grinding spindle to center heightMount proper grinding wheel; true and dressStart lathe, with spindle revolving in reverseStart grinder and adjust grinding wheel until it sparks lightly against revolving center

Grinding a Lathe CenterLock carriage in this positionFeed grinding wheel in .001 in. using crossfeed handleMove grinder along face of center using compound rest feed at a steady pace

Grinding a Lathe CenterCheck angle of center using center gage, and adjust compound rest if necessaryFinish-grind centerPolish center with abrasive cloth at high spindle speed if high finish desired