Drill Bits, Countersinks, Reamers & Counterbores
 Last updated on Wednesday, September 20, 2023 05:35:36 AM Mountain US Time Zone
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Drill Bits, Left-hand Drill Bits, Long Boy,
Silver & Deming, Metric, Tapered Shank, Drill Bit Gauges,
Sharpeners, Center Drill Bits, Stepped Drill Bits,
Circle Cutter, Countersinks, Reamers, Floating Reamer Holder,
Taper-pin Reamers, Counterbores, Engraving Bits,
Combo Drill-Tap Bits, Diamond Wheels, Wood bits, Masonry Bits

Drilling a hole through metal is one of the most basic machining tasks.
However, there are many interacting variables associated with
successful execution thus requiring careful consideration of: the
material to be drilled, rigidity of the setup, depth of hole,
bit design, bit material, bit sharpness, bit length, RPM,
feed rate, chip removal, heat, & lubrication.

Refer to how to drill a hole tutorial &
how to drill the center of a rod.
 Also see Hand Drills & Drill Presses Sections.

Tables
Metric & Inch Equivalents
Inch to Millimeter Conversion Table
Millimeter to Inch Conversion Table
Decimal Equivalents of 8ths, 16ths, 32nds, 64ths
Decimal Equivalents of Letter Size Drills
Decimal Equivalents of Number Size Drills
American Standard Pipe Thread & Tap Drill Sizes
Tap Drill Sizes For Fractional Size Threads
Millimeter Tap Drill Sizes
National /Unified Coarse/Fine Thread Dimensions & Tap Drill Sizes
Cutting Speeds & Feeds for Drills

Drill Bits

Set of USA made fractional (1/16" to 1/2" by 1/64"),
numbered (1-60) & lettered (A-Z) jobber-length HSS drill bits.


Set of HSS micro-drill bits (import) numbered 61 to 80.
In general, the smaller the drill bit, the higher
the required RPM. Clear the chips frequently.

Sets of USA made fractional, numbered & lettered
(Cleveland Forge) stub-length HSS drill bits.
The short stub drill bits afford reduced
flexing & aid use in tight areas.


Set of Dewalt fractional, pilot-point, jobber-length
drill bits (Germany). The shanks have three
flat sides for enhanced chuck gripping.
These split-point bits work nicely on a lathe.

Polished (bright finish): Polished drills do not have a
coating which helps increase chip flow in soft materials.
For use in aluminum, wood, & plastic. Titanium Nitride
(TiN) gold color: Multi-purpose coating that increases tool
life & performance. Hardness & heat resistance allows
running at higher speeds & feeds (25% higher than uncoated).
Black Oxide surface treatment: Retains lubricants to aid in
wear resistance & chip flow. Do not use in non-ferrous materials.

Left-hand Drill Bits
Left-hand HSS drill bit set, 135 deg split-point design,
used to drill a hole in a broken screw or bolt to extract it.
Sizes: 1/4", 15/64", 7/32", 13/64", 3/16", 11/64",
5/32", 9/64", 1/8", 7/64", 3/32", 5/64", & 1/16".


 Left-hand split-point 1/4" cobalt
steel drill bit. Run drill in reverse.


Drill extraction set that has left-handed, split-tip
cobalt drills for harder materials (USA).

Long Boy Drill Bits
Eight-inch, black oxide, HSS long boy
drill bit set 1/8" to 1/2" by 1/64" (import).
The drill bit stand is by Huot (USA).

Silver & Deming (S&D)

 Set of 8, 9/16" to 1" by 1/16" Silver & Deming HSS
drill bits with 1/2" shanks (USA) in a Huot drill bit index.
Clamped parts & low RPM with the proper cutting
fluid are required for successful large-bit hole drilling.



 Set of 33, 1/2" to 1" by 1/64" Silver & Deming HSS drill
bits with 1/2" shanks (import) in a Huot drill storage stand.
I recommend using 3/4" shank S&D drill bits
on large, powerful machines like a Bridgeport.
This stand is heavy-duty due to the overall
weight of holding so many large drill bits.


Set of eight, 1-1/16" to 1-1/2" by 1/16" Silver &
Deming HSS drill bits with 1/2" shanks (import).
The chisel edges (bit geometries) for these bits are
large thus causing chatter & wandering when drilling metal.
Pre-drill the hole with a bit slightly larger than the chisel
edge. Then, just the cutting lip will smoothly drill the hole.
Use low RPM & adequate amounts of the appropriate cutting oil.


 The stand uses 1/4-28 x 2-1/4" bolts, with tube spacers,
threaded into the upper plate. Bolt heads act as feet.


 1-1/2" mounted drill bit in RF-25 mill.


1.5" drilled hole through a 1/4" cold-rolled steel plate.


 Stands afford high-density storage for drill
bits, transfer punch, & transfer screw sets.

Tapered Shank

Long drill bits having MT2 shanks with tang (import)
for use in lathe tailstock or floor drill press.
Sizes are 1/2", 9/16", 5/8", 11/16" & 3/4". 
These are black-oxide treated HSS.

Metric Drill Bits

Set of 1mm to 13mm by 0.5mm,
jobber-length, HSS metric drill bits (USA).


Set of 51, 1mm to 6mm by 0.1mm, jobber-length,
TiN coated HSS metric drill bits in a steel index.


 Set of 50, 1mm to 5.9mm by 0.1mm, jobber-length,
HSS metric drill bits in a Huot index (mixed manufacture).


 Set of 41, 6mm to 10mm by 0.1mm,
jobber-length, HSS metric drill bits in a Huot index.


Micro-drill bit set (carbide). Size marked on the plastic
collar which also acts as a depth stop for setup repeatability.

Drill Bit Gauges
Fractional, numbered, & metric drill bit gauges.


 Metric drill bit gauge 1mm to 13mm by 1/2 mm made out
of 1/4" aluminum plate. A 1/4" hole is on the far right end.

SharpenersSharpeners
Low-cost, all metal drill bit sharpener that uses a bench grinder.
Dress the grinder wheel before use. Grinding attachment manual.


The Drill Doctor 750X uses a 180 grit diamond wheel to sharpen drill bits (manual).
This model affords variable grinding control over several important bit geometries
such as point angle, chisel & relief angles, split-point & amount of material removal.
Use their highest grit diamond wheel available though a higher grit would be better.
All bit grinders require careful, fine adjustments & a consistant delicate touch.


Drill bit stop-collar set to control
hole depth & afford repeatability.


 Split-ring design drill bit stop collars securely clamp OD.
Sizes: 1/8", 3/16", 1/4", 5/16", 3/8", 7/16", & 1/2".

Drilled holes are for clearance. The resulting hole
size is often larger than the drill bit & may not be perfectly round.
 Precision holes are either reamed, ground, or bored.

Center Drill Bits

Different center drill bit (plain type) sizes. KEO is a quality, brand name.
Left to right: #6, #5, #4-1/2, #4, #3, #2, #1, #0. The long, 4" bit is a #2.

CENTER DRILL BIT SIZES
  BODY DIAMETER DRILL BIT DIAMETER DRILL BIT LENGTH OVERALL LENGTH
# inches mm inches mm inches mm inches mm
0 .0938 2.39 .0312 0.79 .0380 0.97 1.125 29
1 .1250 3.18 .0468 1.19 .0468 1.19 1.250 32
2 .1875 4.76 .0781 1.98 .0781 1.98 1.875 48
3 .2500 6.35 .1093 2.78 .1093 2.78 2.000 51
4 .3125 7.94 .1250 3.18 .1250 3.18 2.125 54
4-1/2 .3750 9.53 .1406 3.57 .4063 10.32 2.500 64
5 .4375 11.11 .1875 4.76 .1875 4.76 2.750 70
6 .5000 12.70 .2187 5.56 .2187 5.56 3.000 76

 
Proper center drill bit depth to
accommodate lathe tailstock center.

Stepped Drill Bits

Unibit stepped drill bits are excellent for thin
materials. See Unibit packaging information.

Metric Stepped Drill Bit Set

Metric sized five piece step drill bit set having HSS split-point with cobalt coating, two flutes, & tri-flat shank.
 Metric sizes: 1 Pc, 10mm shank step bit, 13 steps from 6mm to 35mm x 6, 8, 10, 13, 16, 18, 20, 22, 25, 28, 30, 32, 35mm;
1 Pc, 8mm shank step bit, 10 steps from 4mm to 22mm x 2mm; 1 Pc, 8mm shank step bit, 7 steps from 6mm to 18mm x 2mm;
1 Pc, 6mm shank step bit, 9 steps from 4 mm to 12mm x 1mm; 1 Pc, 6mm shank step bit, 5 steps from 4mm to 12mm x 2mm.

Lightweight aluminum storage case included.


The angled shape of each step can be
used to chamfer the hole's sharp edge.



Circle Cutter
Adjustable, large hole cutter that uses a HSS tool bit (USA).
1/2" shank & replaceable 1/4" pilot drill bit.
Cuts sheet metal, brass, copper, aluminum,
plastic, wood & composition materials.
It has an inches scale that adjusts for diameters
from 1-3/4" to 7-7/8". 500 RPM maximum.
General No. 55 circle cutter instructions.

Countersinks

A Weldon zero-flute 82 deg countersink set (USA). The
one center/rear countersink is 100 deg & is used for
flat-head screws when fastening thin sheet metal. These
no-chatter countersinks also deburr holes very well.
They can be sharpened from inside the hole with
a fine round stone or diamond file but these
excellent countersinks have, so far, not required
any maintenance even after heavy use in mild steel.
The (above) USA manufactured countersinks
are superior to most import counterparts.
KEO, Weldon, M.A. Ford, & Irwin are all excellent
countersinks. Low-cost bits invariably chatter.

Chamfer - a cut that is made in material, usually at a 45 deg angle to the adjacent principal faces.

Bevel - usually larger, slanted surface but sometimes used interchangably with chamfer.

Countersink - a conical hole cut into a manufactured object, or the cutter used to cut such a hole.
A common use is to allow the head of a countersunk bolt, screw or rivet, when
placed in the hole, to sit flush with or below the surface of the surrounding material.

Counterbore - a cylindrical, flat-bottomed hole that enlarges another coaxial hole, or the cutter
used to create such a hole. A counterbore hole is typically used when a
fastener, such as a socket head cap screw, is required to sit flush with
or below the level of a workpiece's surface.


Different countersink angles to match bolt head.
100 degs & above are good for thin sheet metal.


60 deg, 82 deg, & 90 deg zero-flute countersink sets.

60, 82, 90 deg ZERO-FLUTE COUNTERSINK SPECIFICATIONS
SIZE DIAMETER CUTTING RANGE (in) SHANK DIAMETER (in)
0 1/16 ~ 15/64 0.0625 ~ 0.2344 1/4
1 5/32 ~ 13/32 0.1563 ~ 0.4063 1/4
2 3/16 ~ 17/32 0.1875 ~ 0.5313 1/4
3 5/16 ~ 25/32 0.3125 ~ 0.7813 1/2
4  9/16 ~ 1-3/32 0.5625 ~ 1.0938 1/2


1" x 82 deg HSS countersink (USA).


Piloted countersinks (10-24 thread) with 0.001"
increment adjustment micro-stop cage adapters.
Sizes: #40 (3/32" pilot), #30 (1/8" pilot), #21
(5/32" pilot), #10 (3/16" pilot) all 100 deg.


A 3/4" (19mm), five-flute reamer/countersink, handy for lathe work.
 General Model #196. 5-1/8" (130mm) overall length.
Handy for deburring a rotating hole on a lathe.


A Table of Decimal Inch Equivalencies for Fractional, Numbered, Lettered & Metric Drill Bits

Fract.
(in)		 Decimal
(in)		 Wire No. Metric
(mm)		   Fract.
(in)		 Decimal
(in)		 Wire No. Metric
(mm)		   Fract.
(in)		 Decimal
(in)		 Letter Metric
(mm)
 
  0.0098   0.25   0.1065 36     0.3480 S  
  0.0118   0.30 7/64 0.1094       0.3543   9.00
  0.0135 80     0.1100 35     0.3580 T  
  0.0138   0.35   0.1102   2.80 23/64 0.3594    
  0.0145 79     0.1110 34     0.3680 U  
1/64 0.0156       0.1130 33     0.3740   9.50
  0.0157   0.40   0.1142   2.90 3/8 0.3750    
  0.0160 78     0.1160 32     0.3770 V  
  0.0177   0.45   0.1181   3.00   0.3860 W  
  0.0180 77     0.1200 31   25/64 0.3906    
  0.0197   0.50 1/8 0.1250       0.3937   10.00
  0.0200 76     0.1285 30     0.3970 X  
  0.0210 75     0.1360 29     0.4040 Y  
  0.0217   0.55   0.1378   3.50 13/32 0.4063    
  0.0225 74     0.1405 28     0.4130 Z  
  0.0236   0.60 9/64 0.1406       0.4134   10.50
  0.0240 73     0.1440 27   27/64 0.4219    
  0.0250 72     0.1470 26     0.4331   11.00
  0.0256   0.65   0.1495 25   7/16 0.4375    
  0.0260 71     0.1520 24     0.4528   11.50
  0.0276   0.70   0.1540 23   29/64 0.4531    
  0.0280 70   5/32 0.1563     15/32 0.4688    
  0.0292 69     0.1570 22     0.4724   12.00
  0.0295   0.75   0.1575   4.00 31/64 0.4844    
  0.0310 68     0.1590 21     0.4921   12.50
1/32 0.0313       0.1610 20   1/2 0.5000    
  0.0315   0.80   0.1660 19     0.5118   13.00
  0.0320 67     0.1695 18   33/64 0.5156    
  0.0330 66   11/64 0.1719     17/32 0.5313    
  0.0335   0.85   0.1730 17     0.5315   13.50
  0.0350 65     0.1770 16   35/64 0.5469    
  0.0354   0.90   0.1772   4.50   0.5512   14.00
  0.0360 64     0.1800 15   9/16 0.5625    
  0.0370 63     0.1820 14     0.5709   14.50
  0.0374   0.95   0.1850 13   37/64 0.5781    
  0.0380 62   3/16 0.1875       0.5905   15.00
  0.0390 61     0.1890 12   19/32 0.5938    
  0.0394   1.00   0.1910 11   39/64 0.6094    
  0.0400 60     0.1935 10     0.6102   15.50
  0.0410 59     0.1960 9   5/8 0.6250    
  0.0420 58     0.1968   5.00   0.6299   16.00
  0.0430 57     0.1990 8   41/64 0.6406    
  0.0433   1.10   0.2010 7     0.6496   16.50
  0.0465 56   13/64 0.2031     21/32 0.6563    
3/64 0.0469       0.2040 6     0.6693   17.00
  0.0472   1.20   0.2055 5   43/64 0.6719    
  0.0512   1.30   0.2090 4   11/16 0.6875    
  0.0520 55     0.2130 3     0.6890   17.50
  0.0550 54     0.2165   5.50 45/64 0.7031    
  0.0551   1.40 7/32 0.2188       0.7087   18.00
  0.0591   1.50   0.2210 2   23/32 0.7188    
  0.0595 53     0.2280 1     0.7283   18.50
1/16 0.0625       0.2340 A   47/64 0.7344    
  0.0630   1.60 15/64 0.2344       0.7480   19.00
  0.0635 52     0.2362   6.00 3/4 0.7500    
  0.0669   1.70   0.2380 B   49/64 0.7656    
  0.0670 51     0.2420 C     0.7677   19.50
  0.0700 50     0.2460 D   25/32 0.7813    
  0.0709   1.80 1/4 0.2500 E     0.7874   20.00
  0.0730 49     0.2559   6.50 51/64 0.7969    
  0.0748   1.90   0.2570 F     0.8071   20.50
  0.0760 48     0.2610 G   13/16 0.8125    
5/64 0.0781     17/64 0.2656       0.8268   21.00
  0.0785 47     0.2660 H   53/64 0.8281    
  0.0787   2.00   0.2720 I   27/32 0.8438    
  0.0810 46     0.2756   7.00   0.8465   21.50
  0.0820 45     0.2770 J   55/64 0.8594    
  0.0827   2.10   0.2810 K     0.8661   22.00
  0.0860 44   9/32 0.2813     7/8 0.8750    
  0.0866   2.20   0.2900 L     0.8858   22.50
  0.0890 43     0.2950 M   57/64 0.8906    
  0.0906   2.30   0.2953   7.50   0.9055   23.00
  0.0935 42   19/64 0.2969     29/32 0.9063    
3/32 0.0938       0.3020 N   59/64 0.9219    
  0.0945   2.40 5/16 0.3125       0.9252   23.50
  0.0960 41     0.3150   8.00 15/16 0.9375    
  0.0980 40     0.3160 O     0.9449   24.00
  0.0984   2.50   0.3230 P   61/64 0.9531    
  0.0995 39   21/64 0.3281       0.9646   24.50
  0.1015 38     0.3320 Q   31/32 0.9688    
  0.1024   2.60   0.3346   8.50   0.9842   25.00
  0.1040 37     0.3390 R   63/64 0.9844    
  0.1063   2.70 11/32 0.3438     1 1.0000    25.40
 
Fract.
(in)		 Decimal
(in)		 Wire No. Metric
(mm)		 Fract.
(in)		 Decimal
(in)		 Letter Metric
(mm)		 Fract.
(in)		 Decimal
(in)		 Letter Metric
(mm)

Reamers

Fractional HSS reamer set (import) 1/16"
to 1/2" by 1/64" in a Huot index case.
See reamer information.


A set of 14, over & under sized (+/-0.001")
decimal HSS chucking reamers (import).
These reamers are +/-0.001" of the standard fractional
sizes: 1/8", 3/16", 1/4", 5/16", 3/8", 7/16", 1/2".

NOMINAL SIZE PLUS 0.0010" MINUS 0.0010"
0.1250" 0.1260" 0.1240"
0.1875" 0.1885" 0.1865"
0.2500" 0.2510" 0.2490"
0.3125" 0.3135" 0.3115"
0.3750" 0.3760" 0.3740"
0.4375" 0.4385" 0.4365"
0.5000" 0.5010" 0.4990"

Drilled holes are for clearance. Precision holes are either
bored, reamed or ground. The hole should be ~1/64"
smaller than the reamer. Chamfer the hole before reaming.
Liberally lubricate the reamer & hole with the proper
cutting oil before starting. To keep a tight tolerance, run
the reamer at the lowest RPM. When the reamer is all
the way through, stop rotation & then withdraw. Running
a turning reamer in & out can increase the hole size.
Chucking reamers have long shafts that
allow some flexing to follow the hole.


Eleven, adjustable, precision hand reamers (India)
for holes from 15/32" to 1-1/2" or .468'' to 1-1/2".
Adjusting the nuts expands the reamer to the
smallest size of the next larger sized tool.
Setting to a precise size is tedious even with a
micrometer; reamed test holes, recommended.
I clamp the shank's square end into the
bench vise & adjust using two, open-end wrenches.


The two nuts move & press the six blades along &
against slants in the bottom of the six grooves. 

ADJUSTABLE REAMER SET SPECIFICATIONS
A 1/2" 15/32" ~ 17/32" 0.468" ~ 0.530" 11.88mm ~ 13.46mm
B 9/16" 17/32" ~ 19/32" 0.530" ~ 0.593" 13.46mm ~ 15.06mm
C 5/8" 19/32" ~ 21/35" 0.593" ~ 0.655" 15.06mm ~ 16.63mm
D 11/16" 21/32" ~ 23/32" 0.655" ~ 0.718" 16.63mm ~ 18.23mm
E 3/4" 23/32" ~ 25/32" 0.718" ~ 0.780" 18.23mm ~ 19.81mm
F 13/16" 25/32" ~ 27/32" 0.780" ~ 0.842" 19.81mm ~ 21.39mm
G 7/8" 27/32" ~ 15/16" 0.842" ~ 0.937" 21.39mm ~ 23.80mm
H 1" 15/16" ~ 1-1/16" 0.937" ~ 1.062" 23.80mm ~ 26.98mm
I 1-1/8" 1-1/16" ~ 1-3/16" 1.062" ~ 1.187" 26.98 mm~ 30.14mm
J 1-1/4"   1-3/16" ~ 1-11/32" 1.187" ~ 1.344" 30.14mm ~ 34.13mm
K 1-7/16" 1-11/32" ~ 1-1/2" 1.344" ~ 1.500" 34.13mm ~ 38.10mm


Chuck capacity is 0.17" to 0.4".
This tap handle holds up to the 3/4" E
hand reamer or 1/4" to 1/2" tap sizes.


Maximum chuck capacity is 0.502".
This larger tap handle holds up
to the 1-1/16" H hand reamer.

Taper-pin Reamers

Tapered pins & tapered reamers.


Taper pins & their taper-pin reamers.
Sizes top to bottom: #2, #1, #0, #3/0, & #4/0.
For short pins, drill the small diameter size.
For long pins, step drilling may be required;
refer to tables in Machinery's Handbook.
 
TAPER REAMER SIZES
SIZE# DIAMETER
SMALL END (in.)		 DIAMETER
LARGE END (in.)
4/0 0.0869 0.1142
3/0 0.1029 0.1302
0 0.1287 0.1638
1 0.1447 0.1798
2 0.1605 0.2008


Tapered hand reamer (USA).

Floating Reamer Holder

Floating holders allow a chamber
reamer to self-align with the barrel.
The floating portion of the holder has a precision-
honed hole. 1/4" & 1/2" shanks use an adaptor bushing.
A set screw secures the tool in the holder (Clymer).
Shown are 22 short rough & finish reamers,
go & no-go gauges plus MT2, 1/2" & 3/8" shanks.

Counterbores
HSS countebore set (Israel): #2, #3, #4, #5, #6, #8, #10, 1/4",
5/16", 3/8", 1/2" with fixed (solid) pilots in a Huot index case.
The pilot size is sometimes labeled on the shaft.
These pilots are sized for free-fit clearance holes.
Clamp the part, use low RPM & the proper cutting fluid to avoid
chatter. It is important to match the pilot hole to the pilot size.

COUNTERBORE SIZES
BOLT SIZE COUNTERBORE SIZE (inches) PILOT SIZE (inches)
#6 - .2420 - .1500
#8 19/64 .2968 11/64 .1718
#10 21/64 .3281 13/64 .2031
1/4" 13/32 .4062 9/32 .2812
5/16" 1/2 .5000 11/32 .3438
3/8" 19/32 .5938 13/32 .4063
1/2" 25/32 .7813 17/32 .5313


Metric counterbore set: M3, M4, M5, M6, M8,
M10, & M12. The shanks are metric sizes, too.


The #6, #8 & #10 counterbores use
interchangeable (3/32" shank) carbon-steel pilots.
Different combinations allow for tighter or
looser fit for the bolt. Pilot sizes: 1/8", 5/32",
 3/16", 7/32", 1/4", 5/16". The 1" counterbore
has 1/2" & 9/16" pilots with 3/16" shanks.
One of the pilots had a burr that needed
to be removed via precision grinding.

A small set screw against a tapered flat holds
the pilot's stem. Detail of a 5/16" pilot.


1" counterbore (USA) with
interchangeable pilots (import).


An example of three counterbores for a 10-32
cap-head bolt (left/center) for a tooling plate.

Engraving Bits

Solid carbide engraving tools for the CNC mill. 
The end was first split in half with a diamond-wheeled
surface grinder then the tip was diamond ground
to have relief behind the single-flute cutting edge.
The point was then relieved even more using a fine diamond file. 


Factory sharpened half round carbide engraver bit.

Combo Drill-Tap Bits

HSS combination drill bit & tap.
Imperial sizes: 4-40, 6-32, 8-32, 10-32, 10-24,
1/4-28, 1/4-20, 5/16-18, 3/8-16 & 1/2-13.


 HSS combination drill bit & tap.
Metric sizes: M3x.5, M4x.7, M5x.8, M6x1, M8x1.25, & M10x1.5
Each bit has integral deburr/countersink & quick-change hex shaft.
The taper after the threading prevents over drilling.


Imperial sizes: 6-32, 8-32,
10-24, 10-32, 12-24 & 1/4-20.

Drill/tap multiple 10-24 threads; lubricate, first.
I disconnected the RF-25 fine down feed & used
the spring-loaded quill arm. Mill set at 110 RPM.
After drilling the hole the tap pulled the quill down.

Diamond Wheels

Assortment of 50, 1/8" shank diamond wheels.


Set of 20, 1/8" shank, diamond pin
grinders. See Tool Post Grinder.
 Wood Bits
Bits for wood & masonry shown for comparative purposes.
Brad-point wood bits (GER) in metric (4, 5, 6, 7, 8, 10 &
12mm) & imperial (1/8, 3/16, 1/4, 5/16, 3/8, 7/16 & 1/2").
A brad point helps to reduce bit wander
as the hole is drilled. Only use in wood.



A set of Forstner-style wood bits (import) that drill
very clean, dimensionally accurate, flat-bottomed holes.
Whenever possible, use a drill press at low RPM,
depth stop & clamp the piece; all of which combine to
produce an accurate hole. Sizes: 1/4" to 2-1/8" by 1/8".
On a project, I was making 5/8" holes for standard
sized wooden dowels but they were a loose fit. So,
I put a 5/8" Forstner bit into the lathe, matched its
 small angle on the compound & removed a small
amount, off the side. Because of this bit's design,
the mod did not change its cutting characteristics.
Bought a single, 5/8" bit to restore the set.
Instead of cutting the bit down, I would now use
the tool post grinder set at the matching angle.


Wood Speedbors (TM).
Sizes: 1/2", 5/8", 3/4", 7/8", 1",1-1/4".


Spade-type, wood drill bits with hexagonal shanks.

Masonry Bits

 Milwaukee Brand masonry bits (USA) with brazed
carbide tips. Work best with a hammer drill.
Sizes: 3/16"x3", 1/4"x4", 5/16"x4", 3/8"x4", 1/4"x6", 1/2"x6".

Drill Bits, Left-hand Drill Bits, Long Boy,
Silver & Deming, Metric, Tapered Shank, Drill Bit Gauges,
Sharpeners, Center Drill Bits, Stepped Drill Bits,
Circle Cutter, Countersinks, Reamers, Floating Reamer Holder,
Taper-pin Reamers, Counterbores, Engraving Bits,
Combo Drill-Tap Bits, Diamond Wheels, Wood bits, Masonry Bits

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