Tungaloy TB, TP & TC 60° Triangle Positive Inserts
Low Cutting Resistance | High Precision Finishing | Ultimate Boring Stability
Which 60° triangular positive insert is best for vibration-free internal boring?
The Tungaloy TB, TP, and TC Series are 60° triangular positive inserts engineered for applications where minimizing cutting force is critical. Unlike negative inserts, these positive geometries (typically 5°, 7°, or 11° relief) reduce tool pressure, making them the industry standard for internal boring, small-diameter turning, and thin-walled workpiece machining. Whether you select the screw-down TCMT, the precision-ground TPGT, or the specialized TBGT, you benefit from Tungaloy's world-class AH725 PVD coating for stainless steel or NS530 Cermet for high-gloss finishing. The 60-degree shape provides excellent clearance, allowing for versatile profiling and finishing in tight CNC lathe setups.
Decoding Tungaloy Positive Triangle Nomenclature
T
Triangle 60°
C / P / B
Relief Angle
M / G
Tolerance
T
Hole/Fix
11 / 16
Size (mm)
03 / T3
Thickness
04 / 08
Radius
Positive Rake Design
Significantly reduces radial cutting forces, preventing chatter in long-overhang boring bars and thin parts.
JS & PS Chipbreakers
Optimized for light-to-medium finishing, ensuring excellent chip evacuation even at low depths of cut (Ap).
Cermet Options (NS530)
Perfect for achieving mirror-like finishes in steel and stainless steel without the need for secondary grinding.
ISO vs. ANSI Reference Table
| ISO Model |
ANSI Model |
Relief Angle |
Primary Use |
| TCMT 110204-PS |
TCMT 21.51-PS |
7° Positive |
General Boring |
| TPGT 110304L-W |
TPGT 221L-W |
11° Positive |
High Precision |
| TBGT 060104L-W |
TBGT 1.21.21L |
5° Positive |
Swiss Lathe |
Suggested Machining Parameters
| Steel Finishing (NS530 Cermet) |
Vc: 150-300 m/min | f: 0.05-0.15 mm/rev |
| Stainless Boring (AH725 Grade) |
Vc: 80-160 m/min | f: 0.03-0.12 mm/rev |
Applications
- High-precision internal boring of hydraulic cylinders.
- Finishing profiles on automotive shafts.
- Small-part machining in medical and aerospace sectors.
- Ideal for Swiss-type lathes and small CNC centers.
Equipment Compatibility
Optimized for all major CNC brands: Mazak, Citizen, Star, Haas, Okuma, and Brother Speedio machines.
Tungaloy Grade Selection Tip
| Grade |
Composition |
Performance |
| AH725 |
PVD Carbide |
Universal, excellent for Stainless and Heat-Resistant Alloys. |
| NS530 |
Uncoated Cermet |
Best for Steel finishing; high wear resistance and finish. |
| T9125 |
CVD Carbide |
High-speed turning of Carbon and Alloy Steels. |
The Beyond CNC Advantage
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Global Industry Feedback
⭐⭐⭐⭐⭐ "Perfect for Swiss Lathes" - J. Miller, USA
"TPGT inserts from Tungaloy are our go-to for medical screws. The ground edges are incredibly sharp and consistent."
⭐⭐⭐⭐⭐ "No More Chatter" - L. Schmidt, Germany
"Switched to TCMT for deep internal boring. The positive rake really helped eliminate the vibration we had with other brands."
⭐⭐⭐⭐ "Mirror Finish on Steel" - F. Rossi, Italy
"NS530 grade is magic. My customers were amazed at the surface finish on the steel shafts. No polishing required."
Technical FAQ
Q: What is the difference between TCMT and TPGT?
A: TCMT is typically a molded-to-size insert (M-tolerance), while TPGT is precision-ground (G-tolerance). TPGT is sharper and more accurate for fine finishing.
Q: Can I use these for Aluminum?
A: For Aluminum, we recommend the uncoated, highly polished Tungaloy KS05F or TH10 grades to prevent built-up edge.
Tech Tip: Boring Overhang
When boring with **TC/TP inserts**, always try to keep the boring bar overhang ratio below 3x Diameter for steel bars. If you must go longer, switch to a Tungaloy Carbide-reinforced bar to maintain precision. **BEYOND CNC** - Machining Excellence.
© Technical Document by Beyond Li - CNC Tooling Technical Director
