Page 322 - YG 2019

TECHNICAL TECHNICAL
DATA DATA

(3) WITHWORTH pipe threads (BSP) 14 ISO Tolerance

Nominal Drill Nominal Drill
size diameter size diameter Drill Diameter Tolerance Inch
inches mm inches mm
G1/8 8.8 G1✽1/4 39.5 up to .118 over .118 up to .236 over .236 up to .394 over .394 up to .709
G1/4 11.8 G1✽3/8 42.0 +0 +0 +0 +0
G3/8 15.25 G1✽1/2 45.0 -.00055 -.00071 -.00087 -.00106
G1/2 19.0 G1✽3/4 51.0
G5/8 21.0 G2 57.0 Drill Diameter Tolerance Metric
G3/4 24.5 G2✽1/4 63.0 Diameter 1 - 3 3 - 6 6 - 10 10 - 18 18 - 30
G7/8 28.25 G2✽1/2 73.0 (mm) from to over to over to over to over to
G1 30.75 G2✽3/4 79.0 h6 0 0 0 0 0
G11/8 35.5 G3 85.0 –.00024 –.00032 –.00036 –.00044 –.00052
0 0 0 0 0
h7 –.0004 –.00048 –.00059 –.00071 –.00083
0 0 0 0 0
(4) American unified coarse threads h8 –.00056 –.00071 –.00087 –.00107 –.00130
Drill diameter Drill diameter +.00048 +.00063 +.00083 +.00099 +.00114
UNC UNC m7
inches mm inches mm +.00007 +.00015 +.00023 +.00027 +.00031
No. 1 53 1.51 7/16 U 9.35
No. 2 50 1.78 1/2 27/64 10.71 15 Trouble Shooting in Drilling
No. 3 47 1.99 9/16 31/64 12.30
No. 4 43 2.26 5/8 17/32 13.49 Occurrence of trouble Cause of trouble Countermeasures
No. 5 38 2.58 3/4 21/32 16.67 1. Drill is dull. 1. Grind lip relief sufficiently.
No. 6 36 2.71 7/8 49/64 19.44 Drill will not enter 2. Lip relief too small. 2. Grind web thinning.
work
No. 8 29 3.45 1 7/8 22.22 3. Too thick a web. 3. Choose a drill with narrow web.
No. 10 25 3.8 1✽1/8 63/64 25.00 Margin chipping 1.Oversized jig bushing. 1. Choose the suitable jig bushing for drill diameter
No. 12 16 4.5 1✽1/4 1✽7/64 28.18 Cutting lip breaks 1. Lip relief too much. 1. Grind lip relief sufficiently.
1/4 7 5.11 1✽3/8 1✽7/32 30.95 2. Feed too heavy. 2. Decrease feed rate.
5/16 F 6.53 1✽1/2 1✽11/32 34.13 Tang breaks 1. Imperfect fit between taper shank and 1. Clean the dirt or chips in sockets.
socket.
3/8 5/16 7.94 Bruch der 2. Burred or Badly worn sockets. 2. Change the worn sockets to new ones.
Drill breaks in brass 1. Unsuitable drill 1. Choose the suitable drill for work material.
2. Flutes clogged with chips
(5) American unified fine threads Chipping of drill 1. Lip relief too much. 1. Grind lip relief sufficiently.
center 2. Feed too heavy. 2. Decrease feed rate.
Drill diameter Drill diameter 1. Unequal angle or length of cutting edges. 1. Resharpening point, choose correct drills.
NF NF Hole oversize
inches mm inches mm 2. Loosen spindle. 2. Tighten spindle sufficiently.
No. 0 3/64 1.19 3/8 Q 8.43 1. Cutting speed too high. 1. Grind point to suit work material.
No. 1 53 1.51 7/16 25/64 9.92 Outer corners 2. Hard spots in work material. 2. Decrease the feed rates.
No. 2 50 1.78 1/2 29/64 11.51 broken down 3. Flutes clogged with chips. 3. Resharpening early beforce too wear.
4. Too wear of drills.
No. 3 45 2.08 9/16 33/64 13.10 Large chip of one 1. Properly grind point.
No. 4 42 2.37 5/8 37/64 14.86 flute and small chip 1. Improperly ground point. 2. Grind point with same point angle and length of lip
2. Only one lip doing all the cutting
No. 5 37 2.64 3/4 11/16 17.46 of other flute 3. Grind with small lip height.
No. 6 33 2.87 7/8 13/16 20.64 1. Improperly ground point. 1. Properly grind point.
No. 8 29 3.45 1 59/64 23.42 Hole rough 2. Unenough coolant supply 2. Supply coolant enough.
No. 10 21 4.04 1✽1/8 1✽ 3/64 26.59 3. Too much feed. 3. Decrease the feed rate.
4. Tighten the fixture or replace.
4. Fixture not rigid.
No. 12 14 4.62 1✽1/4 1✽11/32 29.76
1/4 3 5.41 1✽3/8 1✽19/32 32.94
5/16 1 6.91 1✽1/2 1✽27/64 36.11 16 Characteristic of DREAM DRILLS
- YG-1’s Dream Drill Series are suitable for high speed and accurate drilling operations by special design and high quality.
- Good performance for Steels, Cast Irons, Tool steels, Alloy steels and Stainless steels.
- Rapid chip evacuation and excellent chip breaking can be achieved by special designed cutting edges on point and chip
breakers on leading edges.
- High accuracy and stability.
- Longer tool life with TiAlN coating.
- Self-centering
322 • phone:+1-800-765-8665, Technical Support : 888-868-5988, www.yg1usa.com phone:+1-800-765-8665, Technical Support : 888-868-5988, www.yg1usa.com • 323