Drill Bits, Countersinks, Reamers & Counter-bores
Last updated on Sunday, April 14, 2013 08:09:58 AM Eastern US Time Zone

Drill Bits, Left-hand Drill Bits, Long Boy, Silver & Deming, Metric, Tapered Shank, Drill Bit Gages,
Sharpeners, Center Drill Bits, Stepped Drill Bits, Countersinks, Reamers, Floating Reamer Holder, Taper-pin Reamers,
Counter-bores, 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 variables associated with successful execution thus requiring careful consideration of: the
material to be drilled, setup, bit design, bit material, sharpness, length, RPM, feed rate, chip removal, heat, & lubrication.

Also see, drill presses, how to drill a hole & how to drill the center of a rod.
Decimal Equivalents of Fractions   Decimal Equivalents of # Drills   Decimal Equivalents of Letter Drills
Inch to mm Conversion   mm to Inch Conversion   Metric & Inch Equivalents
Guide for Cutting Speeds & Feeds for Drills   Machinist Calculator

Drill Bits

Set of USA made fractional (1/16" to ½" 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° split-point design, used to drill a hole in a broken screw or bolt to extract it.
Sizes: ¼", 15/64", 7/32", 13/64", 3/16", 11/64", 5/32", 9/64", ⅛", 7/64", 3/32", 5/64", & 1/16".

Left-hand split-point ¼" cobalt steel drill bit. Run drill in reverse.

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

Long Boy Drill Bits

Eight-inch, black oxide, HSS long boy drill bit set ⅛" x ½" x 1/64" (import). The drill bit stand is by Huot (USA).

Silver & Deming

Set of 8, 9/16" to 1" by 1/16" Silver & Deming HSS drill bits with ½" 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, ½" to 1" by 1/64" Silver & Deming HSS drill bits with ½" shanks (import) in a Huot drill bit storage stand.

Set of eight, 1-1/16" through 1½" by 1/16" Silver & Deming HSS drill bits with ½" 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 ¼-28 x 2¼" bolts, with tube spacers, threaded into the upper plate. Bolt heads act as feet.

1½" mounted drill bit in RF-25 mill.

1.5" drilled hole through a ¼" 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 ½", 9/16", ⅝", 11/16" & ¾".  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 (China).

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 Gages

Fractional, numbered, & metric drill bit gages.

Metric drill bit gage 1mm to 13mm by ½mm made out of ¼" aluminum plate. A ¼" hole is on the far right end.

Sharpeners

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.

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

Split-ring design drill bit stop collars securely clamp OD. Sizes: ⅛", 3/16", ¼", 5/16", ⅜", 7/16", & ½".

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 or bored.

Center Drill Bits

Different center drill bit (plain type) sizes. KEO is a quality, brand name.
Left to right: #6, #5, #4½, #4, #3, #2, #1, #0. The long, 4" bit is a #2.

Countersinks

A Weldon zero-flute 82° countersink set (USA). The one center/rear countersink is 100° & is used for
flat-head screws when fastening thin sheet metal. These no-chatter countersinks 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 the (below) import counterparts.

60°, 82°, & 90° zero-flute countersink sets. These imports are barely worth their low cost.
M.A. Ford, KEO, & Weldon are excellent countersinks.

Piloted countersinks (10-24 thread) with 0.001" increment adjustment micro-stop cage adapters.
Sizes: #40 (3/32"pilot), #30 (⅛" pilot), #21 (5/32" pilot), #10 (3/16" pilot) all 100º.


A ¾" (19mm), five-flute reamer/countersink handy for lathe work (General 196). 5⅛" (130mm) overall length.

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