Greenfield Threading
Greenfield Threading CHICAGO-LATROBE 330159 Spiral Point Tap pneumatic accessory
Spiral-point tap cuts 5/16-18 UNC threads in through-holes using three-flute high-speed steel with TiCN coating
- Spiral point pushes chips forward for cleaner threads
- 5/16 in. -18 UNC fits standard coarse threads
- High-speed steel with TiCN coating resists wear
- Three flutes balance strength and chip clearance
- Plug chamfer starts easily in through holes
Thread size and fit
This Greenfield Threading CHICAGO-LATROBE 330159 Spiral Point Tap is a pneumatic accessory for cutting internal threads. It targets a thread size of 5/16 In. -18 UNC with a Class of Fit 2B, making it suitable for general-purpose threading in maintenance and assembly tasks. The right-hand orientation matches standard fastener requirements.
Capacity and headroom
The tap has an overall length of 2 23/32 in and a thread length of 1 1/8 in, providing reach for through-hole applications. Its 75 percent thread drill size F and H3 thread limit define the hole preparation needed for proper engagement. Three flutes and a spiral point design push chips ahead of the cutter to reduce binding in deeper holes.
Upgrade path
This High Speed Steel tool with TiCN coating replaces uncoated or worn taps where longer life and better heat resistance are required. The jump is worth it when threading volume increases or when the material being cut demands the added hardness and lubricity of the coating. It is not for left-hand thread applications or thread sizes other than 5/16 In. -18 UNC.
Highlights
- Spiral point pushes chips forward for cleaner threads
- 5/16 in. -18 UNC fits standard coarse threads
- High-speed steel with TiCN coating resists wear
- Three flutes balance strength and chip clearance
- Plug chamfer starts easily in through holes
Specifications
| Brand | CHICAGO-LATROBE |
|---|
Questions about this item
Will the 5/16 In. -18 UNC tap fit the existing holes in my older fixture plates?
The tap cuts a 5/16 In. -18 UNC thread with a 75 percent thread drill size F; match that spec against your fixture drawings to confirm fit.
How can I verify the CHICAGO-LATROBE 330159 is cutting clean threads after setup?
Run a test piece and check for a 2B class of fit using a go/no-go gauge; the TiCN coating should show even wear across all three flutes.
Does the 330159 Spiral Point Tap come with a matching drill bit or do I buy the size F drill separately?
Only the tap is included; a size F drill for the 75 percent thread depth must be purchased separately.
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