Best Cobalt Multiple Pilot Counterbore

Drill America - DEWPIL1/4X3/16 DEWCBR Series Qualtech High-Speed Steel Pilot for Counterbore, 3/16\ Shank Diameter, 1-3/4\ Length, 1/4\ Size (Pack of 1)

High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance.
Available in 1-3/4-inches overall length.

STUBBY MECHANICS LENGTH: 135 degree split point reduces drill walking, straight shank.
MADE FROM HIGH-SPEED STEEL AND 5% COBALT: improve much higher heat resistance because of cobalt steel's high red hardness, provide strong durable performance compared to typical hss drill bits.
CAN BE REPEATEDLY SHARPENED AS NEEDED: cobalt drill bit's hardness is uniform throughout the entire material, so that can be repeatedly sharpened without damaging the cutting edge allowing it to drill more than hss drill bits.
APPLICATION: best used for removing damaged bolts and screws, or drilling a pilot hole for a screw extractor.
INCLUDE: 2pcs 5/64 inch, 2pcs 7/64 inch, 1pc 5/32 inch, 1pc 1/4 inch and 1pc 19/64 inch cobalt left hand drill bits with case.

[SIZE] - M8x1.25mm thread size, 0.39" (10mm) long, 0.39" 10mm outer diameter ,OD tolerance: +0.02"/0"..
[MATERIAL] - Made of brass, rust resistance, good thermal conductivity and heat resistance, can ensure long time using..
[FEATURE] - Can be installed by ultrasonic or heat into thread tapered hole, or in during injection..
[ADVANTAGE] - No need to counterbore or countersink the boss hole since the insert has guide pilot..
[APPLICATION] - Widely used on injection for fastening..

High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance.
Round shanks allow use with a wide variety of toolholding systems.
Counterboring is the enlargement of a portion of a hole that has previously been formed.
The counterbor is a two-piece construction, having an integral shank and counterbore-cutter, and a pilot that is interchangeable, which provides flexibility in the use of the tool.

Manufactured to NAS 907 Type J geometry aerospace specifications with self-centering 135-degree split point penetrates hard material without a pilot hole and produces small chips to reduce clogging and gold oxide is a thinner oxide surface treatment than black oxide typically used to identify cobalt steel tools.
performance is similar to uncoated tools.
Heavy duty construction for increased strength and rigidity compared to standard drill bits.
Cobalt steel tools are similar to high-speed steel, but with more cobalt for improved performance when cutting harder metals such as stainless steel or nickel alloys.

All-in-one kit – features two SpinLOCK Universal arbors, steel pilot bit and six hole saws with Progressor tooth design.
SpinLOCK universal arbor – fits all brands and sizes to simplify diameter changes with fast plug removal and tool-free install.
The pilot bit – designed to start holes in a variety of materials.
Progressor tooth design – hole saws feature alternating teeth size for performance, cutting faster and lasting longer in wood, metal and plastic materials.
Durable hole saw material – hole saws are made with 8% cobalt alloy.

Set includes 1/16", 5/64", 3/32", 7/64", 1/8", 9/64", 5/32", 11/64", 3/16", 13/64", 7/32", 15/64", 1/4", 17/64", 9/32", 19/64", 5/16", 21/64", 11/32", 23/64", 3/8", 25/64", 13/32", 27/64", 7/16", 29/64", 15/32", 31/64" and 1/2" cobalt drill bits.
Century Pro Grade drills are made from 5% industrial quality M35 cobalt alloy high speed steel..
Cobalt is extremely heat resistant, when used and operated in power units that have a RPM speed of 1,500 or more for maximum efficiency..
Lasts up to 12 times longer than the average consumer-grade high speed steel drill..
135 degree quick-cut point penetrates faster and will not walk or wander at the starting surface. Does not require a center punch or pilot hole..

COBALT STEEL - Manufactured from M35 grade cobalt steel, with molybdenum and cobalt added to creates a hardened alloy, measuring Rockwell hardness up to 67, for much faster cutting and extra longer life span, ideal for repeated drilling in metalworking..
FOR METALWORKING - Particularly successful in cutting through hard metals(hardness less than HRC38°) such as stainless steel and cast iron, although they can be used for softer materials like copper and aluminium, too. Not for hardened steel / high carbon steel. Try to adjust the RPM when it fails to penetrate..
SELF CENTERING - The 135°quick-cut pilot split points are self-centering and can penetrate quickly with less pressure. The bits will not "walk" or "wander". Straight shank allows for firmly holding and accurate centering, fit for standard drill chucks and regular round collet chucks..
5PC SET - The set includes 5pcs of 3/8” diameter M35 grade cobalt steel twist drill bits, packed in a convinient and reuseable PVC case for easy storage and carrying. Manufactured to German DIN338 standard..
DOWNLOADABLE USER GUIDE - We've summed up some tips of drilling metals, including a RPM chart for several common metals, based on our reviews and some articles on the internet. In most cases, our customers w....

Spotting drill bit creates a pilot hole to reduce walking and improve hole accuracy.
Solid carbide drills produce close-tolerance holes in hard materials, and have a longer tool life at higher speeds than cobalt and high-speed steel (HSS).
Uncoated (bright) finish has no additional surface treatment or coating.
120-degree conventional point drills a pilot hole to accurately guide a 118-degree secondary drill bit.
Round shank accommodates most drill chucks.