Cleveland Golf
Cleveland Golf Jobber Drill 5/16 Cobalt 135 Deg Blk Oxide 3780
A 5/16-inch cobalt jobber drill bit with 135-degree split point and black-oxide finish for heavy-duty alloy and stainless steel drilling
- TypeAngle, Pitch & Slope Locators
- 5/16 in. cobalt steel drills alloy and stainless steel
- 135-degree split point starts on contact without walking
- Black oxide finish resists wear in heavy-duty use
- 3-3/16 in. flute length clears chips at 4xD depth
- Jobber-length 4-1/2 in. shank fits standard chucks
Cleveland Jobber Drill 5/16 Cobalt
This cobalt steel jobber drill bit handles alloy, carbon, stainless and tool steel with a 135 degree split point that starts on contact. The black oxide finish reduces friction and resists corrosion during repeated use. It suits maintenance technicians and machinists who need a heavy-duty fractional bit for general-purpose drilling.
4-1/2 Inch Overall Length 3-3/16 Inch Flute
The straight shank matches the 5/16 inch diameter so the bit fits standard drill chucks without a reduced-shank adapter. A 4x diameter-to-depth ratio lets you reach deeper holes in a single pass. Right-hand spiral flutes clear chips efficiently whether you are on a drill press or a handheld motor.
Cobalt Steel Holds Edge Under Heat
Cobalt alloy retains hardness at elevated temperatures generated by sustained drilling in tough steels. The split point reduces walk and thrust, lowering the load on both the bit and the machine spindle. Black oxide surface treatment helps dissipate heat during long production runs.
Highlights
- 5/16 in. cobalt steel drills alloy and stainless steel
- 135-degree split point starts on contact without walking
- Black oxide finish resists wear in heavy-duty use
- 3-3/16 in. flute length clears chips at 4xD depth
- Jobber-length 4-1/2 in. shank fits standard chucks
Specifications
| Brand | Cleveland |
|---|---|
| Type | Angle, Pitch & Slope Locators |
Questions about this item
At what point angle does the 135-degree split point start to wander in deep holes?
The 135-degree split point is designed for self-centering and reduced thrust, maintaining accuracy up to the 4xD depth-to-diameter ratio for alloy, carbon, stainless and tool steel.
How hot does the cobalt steel body get during continuous drilling in stainless steel?
Cobalt steel retains hardness at elevated temperatures generated in stainless and tool steel, while the black oxide finish aids heat dissipation and chip flow during extended use.
Which chuck size is required to grip the 5/16-inch shank on this drill bit?
A 5/16-inch or larger capacity drill chuck is needed to secure the straight shank, which matches the 5/16-inch drill diameter and 4-1/2-inch overall length.
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