SRACL2020K12 External Turning Tool Holder for RCMT Inserts – BEYOND
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SRACL2020K12 External Turning Toolholder
Professional 20x20mm Left-Hand Shank for RCMT1204 Round Inserts
Product Overview
"Which left-hand 20mm toolholder is best for achieving high-stability profiling and smooth radius contouring with 12mm round inserts?"
The Beyond SRACL2020K12 is a precision-engineered external turning toolholder designed specifically for RCMT1204 (and RCGT) round inserts. In specialized CNC machining, round inserts are the gold standard for edge strength, as they lack the weak points of traditional diamond or triangular tips. This 20x20mm shank model is optimized for left-hand operations where high vibration damping and superior thermal distribution are required for profiling complex contours in steel, stainless, and high-temp alloys.
Key Features
- ✔ Quenched 42CrMo Steel: Forged from high-alloy steel and heat-treated to HRC 42-45 for maximum durability.
- ✔ Screw-Down Clamping Stability: The S-type clamping mechanism provides a low-profile head and massive holding power for profiling.
- ✔ Enhanced Surface Finish: Black oxide coating resists corrosion and prevents chip welding during high-temp operations.
Technical Specifications
Screw Clamp
Round Shape
90° Approach
7° Relief
Left Hand
20x20mm
125mm Len
RCMT12
| ISO Parameter | Metric (mm) | Imperial (inch) |
|---|---|---|
| Shank Size (H x W) | 20 x 20 mm | 0.787" x 0.787" |
| Total Length | 125 mm | 4.92" |
| Insert Size | RCMT 1204** | Round 1/2" |
Recommended Cutting Parameters
| Material Group | Speed (Vc) | Feed Rate (f) |
|---|---|---|
| Steel (P) | 150 - 250 m/min | 0.15 - 0.45 mm/rev |
| Cast Iron (K) | 130 - 210 m/min | 0.12 - 0.40 mm/rev |
Required Insert: RCMT 1204** / RCGT 1204**
Specifically designed for 12mm round inserts for maximum profiling efficiency.
Shop RCMT12 Inserts →Primary Applications
- High-Rigidity Profiling & Contouring
- Large Radius Fillet Machining
- Internal Back-Turning (Setup Dependent)
- Medium-Roughing to Finishing in Tough Materials
Compatibility
Compatible with CNC turrets and conventional tool posts designed for 20mm (3/4") square shanks. Fits standard RCMT 12 series inserts from Beyond, Mitsubishi, and Sandvik.
Beyond Brand Material Comparison
The Rigidity Factor: While entry-level 20mm holders often use standard carbon steel, Beyond utilizes high-alloy 42CrMo steel. Our specialized quenching process results in 30% higher damping capacity, which is vital when taking deep cuts with a 12mm radius insert. This prevents micro-chatter, resulting in superior surface finishes and extended carbide tool life.
Verified B2B Success
"Excellent rigidity for a 20mm shank. I use this for roughing large fillets and it stays rock solid. The 12mm round insert lasts forever on this shank."
— Robert D., USA"Qualität ist erstklassig. Die RCMT12 Platten sitzen fest und sicher. Beste Wahl für schwere Zerspanung auf kleineren Maschinen."
— Dieter W., Germany"Excellent toolholder for profiling. The finish on cast iron is impressive when using the 12mm radius."
— Marco V., Italy"Beyond toolholders are consistently reliable. Accuracy is equal to top-tier brands but at a better price for our shop."
— Kenji S., JapanFrequently Asked Questions
Is this compatible with RCGT inserts?
Yes. The SRACL2020K12 is fully compatible with both RCMT and RCGT 1204** inserts, allowing you to switch between steel and aluminum/non-ferrous profiling easily.
What is the benefit of a Left-Hand (L) holder?
Left-hand holders are used for machining from the tailstock toward the spindle or on specific CNC turret configurations that require left-hand approach angles.
Are the screw and wrench included?
Yes, every Beyond toolholder comes with a high-tensile clamping screw and the corresponding Torx wrench.
Material Pro Tip: High-Feed Radius Advantage
When roughing with the SRACL2020K12, the 12mm round insert allows for significantly higher feed rates compared to standard diamond inserts. Because the edge is stronger, you can increase your depth of cut to maximize metal removal rates without risking tool breakage.
Technical FAQ & Buying Guide
Absolutely. Our CNC carbide inserts (including CNMG, WNMG, DNMG, and APMT series) are manufactured strictly adhering to international ISO/ANSI specifications. A CNMG 120408 from OYYU BEYOND will flawlessly fit any standard turning tool holder or indexable tool from major global brands like Sandvik Coromant, Kennametal, Iscar, Walter, or SECO, providing a highly cost-effective premium alternative without sacrificing tolerance or tool life.
We offer optimized CVD and PVD multi-layer coatings for different ISO material groups:
- For Carbon/Alloy Steel (ISO P): Choose our thick multi-layer CVD coated grades (e.g., Al2O3 + TiN). They provide exceptional crater wear resistance and thermal barriers during high-speed dry or wet roughing.
- For Stainless Steel (ISO M): Choose our nano-structured PVD coated grades with sharp, positive chipbreakers (like -TM or -MA). This combination prevents work hardening and effectively controls sticky chips.
The optimal cutting parameters vary depending on the workpiece hardness and operation type:
- For General Steel Turnings: Recommended cutting speed ($V_c$) ranges from 150 to 280 m/min, with a feed rate ($f$) of 0.15 to 0.45 mm/rev.
- For Stainless Steel Finishing: Recommended cutting speed ($V_c$) is 120 to 200 m/min, with a feed rate ($f$) of 0.10 to 0.25 mm/rev.Always adjust parameters based on early wear patterns: increase $V_c$ if built-up edge occurs, or reduce $V_c$ if severe flank wear is observed.
Yes, we support machine shops, distributors, and global buyers with tiered wholesale pricing and competitive volume discounts. We also provide OEM custom manufacturing solutions for tool holders and carbide inserts based on your technical drawings. Contact our team to request a quick B2B quotation.
We provide secure worldwide express shipping (via DHL, FedEx, and UPS) with specialized, vibration-proof industrial packaging to ensure tools arrive in perfect condition. In-stock items are dispatched within 24-48 hours, while custom or bulk orders typically have a stable lead time of 15-25 days.
All our cutting tools and tool holders are manufactured strictly in accordance with ISO 9001 and international industrial standards. Every batch undergoes 100% rigorous quality control testing using high-precision optical measuring equipment to ensure reliable tool life and stable performance in continuous mass production.