Widia Gtd
Widia Gtd VTSFT-TC5151 Spiral Flute Tap 5/16"-18 Bottoming 2 Flutes UNJC pneumatic accessory
A spiral-flute tap cuts 5/16"-18 UNC threads in blind holes using three flutes and a bottoming chamfer
- Spiral flute design clears chips efficiently in blind holes
- 5/16"-18 UNC thread size fits standard coarse-pitch applications
- Bottoming chamfer cuts full threads to hole bottom
- High-speed steel with black oxide resists wear and corrosion
- Three flutes balance strength and chip evacuation capacity
Precision thread cutting for UNC applications
The Widia Gtd VTSFT-TC5151 spiral flute tap produces 5/16"-18 UNC threads in a bottoming configuration. High-speed steel construction with a black oxide finish resists wear during repetitive machining tasks. Three flutes evacuate chips efficiently while maintaining alignment in through-hole or blind-hole work. This tool suits maintenance technicians and metalworkers who need reliable internal threading.
Heat and wear management in daily use
The black oxide surface treatment reduces friction between the tap and workpiece, limiting temperature rise during extended cutting cycles. High-speed steel retains hardness at the elevated temperatures typical of steel and alloy threading. Three-flute geometry distributes cutting forces evenly, lowering the torque spike that can cause chatter or premature dulling. No external lubrication system is required beyond standard cutting fluid practice.
Replaces worn or undersized taps in UNC workflows
This tap replaces a dull or damaged 5/16"-18 UNC bottoming tool when thread quality falls below 2B class-of-fit requirements. The H5 thread limit and 75 percent thread drill size F match standard UNC specifications, so the upgrade is worthwhile when existing taps no longer hold tolerance. It does not address metric, UNF or pipe-thread needs, nor does it suit high-volume CNC operations that demand coated carbide tooling.
Highlights
- Spiral flute design clears chips efficiently in blind holes
- 5/16"-18 UNC thread size fits standard coarse-pitch applications
- Bottoming chamfer cuts full threads to hole bottom
- High-speed steel with black oxide resists wear and corrosion
- Three flutes balance strength and chip evacuation capacity
Specifications
| Brand | WIDIA |
|---|
Questions about this item
How do I install the 5/16"-18 spiral flute tap and what step is often missed?
Secure the workpiece, use a drill size F hole for 75 percent thread, apply cutting fluid, and start the tap straight. The step often missed is keeping the tap perpendicular during the first few turns to avoid cross-threading.
What maintenance or replacement will the high-speed steel tap with black oxide finish need later?
The cutting edges dull with use; resharpen or replace the tap when thread quality drops or torque rises. Black oxide coating wears off over time but does not affect function.
What limit appears first during sustained threading with the H5 thread limit and 2 23/32 in overall length?
Chip evacuation in deep holes becomes the limiting factor; the 11/16 in thread length and spiral flute design help, but continuous cutting can pack flutes and increase torque.
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