Micro 100
Micro 100 DR-312-2 5/16" Carbide Jobber Drill Bit 118 Deg
A 5/16 inch carbide jobber drill bit with a 118 degree point angle for general-purpose drilling
- Carbide construction resists wear for long tool life
- 118-degree point angle centres quickly on contact
- Jobber length handles standard-depth holes efficiently
- Bright uncoated finish suits general-purpose drilling
- Decimal equivalent 0.3125 matches 5/16 inch size
Micro 100 Carbide Jobber Drill Bit
The Micro 100 DR-312-2 is a 5/16 inch carbide jobber drill bit built for machining hard materials. Its conventional 118-degree point suits general-purpose drilling in steel, cast iron and non-ferrous alloys. The bright uncoated finish avoids coating buildup in abrasive or sticky workpieces. Machinists and maintenance technicians choose it when high-speed steel wears too quickly.
Jobber Length Practical Limits
Jobber length gives enough flute reach for holes up to roughly five diameters deep in a single pass. Beyond that depth chip evacuation suffers and the bit can wander without peck cycles or through-coolant. The conventional 118-degree point needs higher thrust than split-point designs and can walk on curved or hardened surfaces. No coolant-through hole means external flood or mist is required for deep cuts.
Upgrade From High-Speed Steel Bits
This carbide bit replaces high-speed steel jobbers when tool life or cutting speed is the bottleneck. The jump pays off in high-volume production, tough alloys or abrasive composites where HSS dulls in minutes. It is not for hand-held drilling, low-rigidity setups or interrupted cuts where carbide’s brittleness causes chipping. Buyers who need through-coolant delivery or a split-point for self-centering should select a different tool.
Highlights
- Carbide construction resists wear for long tool life
- 118-degree point angle centres quickly on contact
- Jobber length handles standard-depth holes efficiently
- Bright uncoated finish suits general-purpose drilling
- Decimal equivalent 0.3125 matches 5/16 inch size
Specifications
| Brand | MICRO 100 |
|---|
Questions about this item
Should I choose the 5/16 inch or .3125 decimal size for my project?
Both figures describe the same 5/16 inch diameter; .3125 is the decimal equivalent used for precision setups.
What does the 118 degree point angle mean when I am drilling?
The 118 degree conventional point centres quickly in steel and general metal without walking.
How does the carbide material affect drilling performance?
Carbide holds a sharp edge longer than high speed steel, giving extended life in abrasive or hardened materials.
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