Chicago-Latrobe
Chicago-Latrobe 45691 135 Degree Heavy-Duty Jobber Length Drill Bit #21
A #21 jobber-length drill bit with a 135-degree split point and black-oxide finish for general-purpose drilling
- TypeDrill Bits
- MaterialHAWA
- #21 drill bit size for precise wire-gauge holes
- 135-degree split point starts fast without wandering
- High-speed steel with black oxide resists wear
- .1590 decimal equivalent matches exact specifications
- Jobber length 45691 handles general-purpose drilling
Chicago-Latrobe #21 Jobber Drill Bit
This Chicago-Latrobe 45691 drill bit is a jobber-length tool sized #21 with a decimal equivalent of .1590. It is made from high-speed steel with a black oxide finish for general-purpose drilling in metal, wood and plastic. The 135-degree split point is designed to start on contact and reduce walking. It is sold new for workshop and maintenance tasks.
135 Degree Split Point Geometry
The split-point tip centres the bit without a centre punch, saving set-up time on repetitive holes. A straight shank fits standard three-jaw chucks on corded or cordless drill drivers and drill presses. No coolant holes are present, so the bit relies on external lubrication or peck drilling for deeper cuts. The jobber length provides a standard reach for through-holes and blind holes alike.
Suited for General Maintenance Drilling
This bit suits technicians and hobbyists who need a single #21 high-speed steel drill for occasional use. It is not intended for high-volume production runs where cobalt or carbide tooling would last longer. Buyers who need a full index of sizes or a bit with through-coolant capability should look at other options. The black oxide coating offers basic corrosion resistance during storage.
Highlights
- #21 drill bit size for precise wire-gauge holes
- 135-degree split point starts fast without wandering
- High-speed steel with black oxide resists wear
- .1590 decimal equivalent matches exact specifications
- Jobber length 45691 handles general-purpose drilling
Specifications
| Brand | CHICAGO-LATROBE |
|---|---|
| Type | Drill Bits |
| Material | HAWA |
Questions about this item
At what point angle does the 135-degree split point start to wander in hardened steel?
The 135-degree split point is designed to self-centre and reduce walking in tough materials, so the limit appears when the workpiece hardness exceeds what high-speed steel can cut cleanly.
How hot does the black-oxide finish get during a full day of drilling #21 holes?
Black oxide helps dissipate heat, but sustained high-speed drilling in steel will still raise the bit temperature enough to require cutting fluid or frequent pauses to avoid temper loss.
What shank size must my drill chuck accept for the #21 jobber bit?
A #21 jobber-length bit has a 0.1590-inch diameter shank, so the chuck must open to at least that size — most 3/8-inch or 1/2-inch keyed or keyless chucks will hold it.
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