Greenfield Threading
Greenfield Threading Spiral Point Tap Plug 330157 pneumatic accessory
Spiral point tap cuts 1/4"-20 UNC threads in through-holes with three flutes and TiCN coating
- Spiral point design pushes chips forward for cleaner threading
- High-speed steel with TiCN coating resists wear during repeated use
- Three flutes balance chip clearance and cutting strength
- 1/4-20 UNC thread size fits standard coarse-pitch applications
- Right-hand cut with H3 limit produces Class 2B fit
Greenfield Spiral Point Tap 330157
This Greenfield Threading spiral point tap is a pneumatic accessory designed for creating internal threads in through-holes. It suits machinists and maintenance technicians who need a high-speed steel cutting tool with a TiCN coating for extended wear life.
Suits UNC 1/4-20 right-hand threading.
The plug chamfer and spiral point design push chips ahead of the cut, making this tap suitable for through-hole applications in materials compatible with high-speed steel. It is not for blind-hole work where chips must be pulled upward, nor for left-hand thread requirements or thread forms other than Unified National Coarse.
1/4 In. -20 UNC thread size with H3 limit
The decisive specification is the 1/4 In. -20 UNC thread size combined with an H3 thread limit and Class of Fit 2B, which determines whether this tap matches the required hole geometry and tolerance for the intended fastener assembly.
Highlights
- Spiral point design pushes chips forward for cleaner threading
- High-speed steel with TiCN coating resists wear during repeated use
- Three flutes balance chip clearance and cutting strength
- 1/4-20 UNC thread size fits standard coarse-pitch applications
- Right-hand cut with H3 limit produces Class 2B fit
Specifications
| Brand | CHICAGO-LATROBE |
|---|
Questions about this item
What thread size and drill size does the 330157 tap require?
The tap cuts 1/4 In. -20 UNC threads and needs a #7 drill for 75 percent thread engagement.
How do I start the 330157 spiral-point tap in the hole without cross-threading?
Align the tap square to the drilled hole, apply steady forward pressure, and let the spiral point push chips ahead as you turn.
When should I replace the 330157 high-speed steel tap?
Replace it when cutting edges dull, threads gauge oversize, or chip evacuation slows despite proper lubrication.
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