Charts

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Suggested Drilling Feed Rates

suggesteddrillingfeedrateschart.pdf

Suggested Drilling Feed Rates (inches per rev.)

MATERIAL BRINELL    HARDNESS HOLE DIAMETER
1/16″ 1/8 1/4 1/2 3/4 1 1 1/2 2
Aluminum 99-101 .001 .003 .007 .012 .016 .020 .025 .030
Aluminum Bronze 170-187 .001 .003 .004 .008 .010 .012 .015 .020
Balkelite .002 .005 .006 .008 .010 .012 .015 .015
Brass 192-202 .001 .003 .004 .008 .012 .018 .020 .022
Bronze, Common 166-183 .001 .003 .004 .008 .012 .018 .020 .022
Bronze Phos.; 1/2 Hard 187-202 .001 .003 .004 .008 .010 .012 .015 .020
Bronze Phos.; Soft 149-163 .001 .003 .004 .008 .012 .018 .020 .022
Celluloid .002 .004 .005 .006 .006 .008 .008 .010
Copper 80-85 .001 .003 .004 .008 .010 .012 .015 .020
Copper Mang.; 30% Mn 134 .001 .003 .005 .007 .009 .012 .014 .016
Duralumin 90-104 .001 .003 .005 .010 .015 .018 .020 .025
Iron, Cast; Med Soft 196 .001 .003 .005 .008 .010 .012 .014 .015
Iron, Cast; Hard 293-302 .001 .003 .005 .007 .009 .012 .012
Iron, Cast; Chilled 402 .001 .003 .005 .007 .009 .011 .011
Iron, Malleable 112-126 .002 .004 .007 .010 .012 .015 .018
Monel 149-170 .002 .003 .006 .008 .010 .012 .015
Nickel, Pure 187-202 .002 .003 .006 .008 .015 .018 .020
Nickel, Steel; 3 1/2% 196-241 .002 .003 .006 .008 .010 .012 .015
Rubber, Hard .005 .010 .012 .015 .018 .020 .025 .030
Screw Stock, C.R. 170-196 .001 .003 .004 .007 .010 .012 .015 .018
Stl, Carbon 175-225 .001 .003 .004 .007 .010 .012 .015 .018
Stl, Drop Forged 170-196 .001 .002 .004 .007 .010 .012 .015 .018
Stl, Machinery 170-196 .001 .003 .005 .009 .012 .013 .018 .022
Stl, Magnet; Soft 241-302 .002 .003 .006 .008 .009 .010 .011
Stl, Magnet; Hard 321-512 .0005 .001 .002 .002 .003 .003 .004
Stl, Mang.; 7-13% 187-217 .0005 .001 .002 .002 .003 .003 .004
Stl, Mild; .20-.30C 170-202 .001 .003 .005 .010 .015 .018 .020 .025
Stl, Molybdenum 196-235 .002 .004 .006 .010 .012 .015 .018
Stl, Spring 402 .002 .003 .005 .007 .009 .010 .010
Stl, Stainless 150-225 .001 .002 .004 .006 .008 .011 .013 .016
Stl, Stainless 460-520 .0005 .001 .002 .002 .003 .003 .004
Stl, .40-.50C 170-196 .001 .002 .004 .007 .010 .012 .015 .018
Stl, Struct; A-36 160 .001 .003 .005 .010 .015 .018 .020 .025
Stl, Tool; SAE, Forged 149 .002 .003 .006 .009 .011 .014 .016
Stl, Tool; SAE, Forged 402 .0005 .001 .002 .002 .003 .003 .004
Zinc, Alloy 112-126 .002 .003 .007 .012 .016 .018 .020 .025

Recommended Drill Head Pressure

RecommendedDrillHeadPressureChart.pdf

Recommended Drill Head Pressure

HK Diamond Core Drill Bits Material Recommended Drill Head Pressure (lbs.)*
Fiberglass 10 to 15 lbs.
Limestone & Marble Stone 12 to 18 lbs.
Glass, Ceramic & Porcelain China 12 to 18 lbs.
Ceramic/Porcelain Wall Tile 15 to 20 lbs.
Stone Style Porcelain Floor Tile 18 to 30 lbs.
Granite Stone 18 to 30 lbs.

*WARNING:  Drill press arms leverage hand pressure by a factor of about 6 to 8.  So 2 lbs. of hand pressure on the drill press arm will apply about 14 lbs. of pressure to the drill head.

If a drill bit develops yellow, brown, blue or black ‘burn marks’ around the tip, it is an indication of extreme heat caused by the excessive drill speed or by too much pressure on the drill.  Impact type “hammer drills” should never be used with diamond drills as they have no benefit and will cause the tip of the bit to mushroom or split.

If a hole is being drilled completely through a piece of material, it is also important to “lighten up” considerably on the pressure when the drill bit is near the back of the material.  This reduces chipping or fracturing on the back of the material when the bit emerges from the back. Using a similar “backer” material may also help prevent accidental and damaging breakthroughs.

Hardness Scale Chart

HardnessScaleChart.pdf

Knoop
Hardness Scale

Material
Wood – Pine 10
Copper 120
Limestone 125 – 150
Marble 140 – 180
Slate 140 – 250
Porcelain Fixtures & China 400 – 500
Glass & Ceramic 400 – 550
Ceramic Wall Tile 450 – 550
Porcelain Wall Tile 500 – 650
Porcelain Floor Tile 500 – 650
Marble Style Porcelain Floor Tile 500 – 650
Granite Style Porcelain Floor Tile 500 – 650
Granite 550 – 650
Quartz 820
Common Tool Steel 700 – 900
Tungsten Carbide 2,000
Diamond 7,000