Chicago-Latrobe
Chicago-Latrobe 50503 118 Degree Heavy-Duty Extra Long Drill Bit
Extra-long 5/16 inch drill bit with 118-degree notched point, high-speed steel construction and black oxide finish for deep drilling up to 5-1/2 inches
- Extra reach with 5-1/2 in maximum drilling depth
- 118-degree notched point starts holes cleanly
- High-speed steel with black oxide resists wear
- 28-degree helix clears chips efficiently
- General-purpose grade suits varied materials
Chicago-Latrobe 50503 5/16" Extra Long Drill Bit
The Chicago-Latrobe 50503 is a high-speed steel drill bit designed for deep-hole drilling tasks. Its extra-long body and 118-degree notched point suit machinists and maintenance crews needing extended reach in general-purpose materials. The black oxide finish adds wear resistance during repetitive use. Fractional inch sizing ensures compatibility with standard imperial tooling setups.
118-degree notched point and 28-degree helix angle
The 118-degree notched point centres quickly without a pilot hole, reducing wandering on flat surfaces. A 28-degree helix angle promotes steady chip evacuation at standard drilling speeds. Black oxide coating lowers friction and resists corrosion during prolonged contact with ferrous metals. High-speed steel construction maintains edge hardness under normal cutting temperatures.
5-1/2 inch maximum drilling depth at 4xD ratio
The 4xD length-to-diameter ratio provides a maximum drilling depth of 5-1/2 inches for deep through-holes or blind cavities. Sustained feed pressure is manageable thanks to the notched point geometry reducing thrust force. Chip packing risk rises with depth, so periodic withdrawal clears flutes effectively. The bit retains dimensional accuracy across repeated cycles in general-purpose machining.
Highlights
- Extra reach with 5-1/2 in maximum drilling depth
- 118-degree notched point starts holes cleanly
- High-speed steel with black oxide resists wear
- 28-degree helix clears chips efficiently
- General-purpose grade suits varied materials
Specifications
| Brand | CHICAGO-LATROBE |
|---|
Questions about this item
How do I install the 50503 extra-long bit without it walking on the first hole?
Clamp the workpiece, centre-punch the spot, and start the 118-degree notched point at low RPM with steady pressure; the notch centres the bit so it does not wander before the flutes engage.
When will the 50503 bit need replacement or re-sharpening?
The high-speed steel cutting edges dull gradually; re-sharpen the 118-degree point on a bench grinder when chips turn powdery or feed force rises noticeably.
What limit appears first during sustained drilling with the 50503 bit?
Chip evacuation in the 5-1/2-inch deep flutes becomes the bottleneck; withdraw the bit every 28 degrees of rotation to clear swarf and prevent binding.
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