Kyocera 1/2 Micro-Grain SGS38259 Endmill | 2FL-Milling | Kyotow.com

Product Overview

The Kyocera SGS38259 is a premium 1/2-inch diameter, 2FL solid carbide endmill engineered for high-performance CNC milling operations. This tool features a 0.015R corner radius on a uncoated micro-grain carbide substrate, delivering exceptional wear resistance and dimensional stability across extended production runs. Features a precision Weldon flat for secure set-screw retention in standard endmill holders. The 2-flute design provides generous chip pocket volume and superior chip evacuation, making the SGS38259 ideal for slotting, pocketing, and contouring in aluminum, plastics, and steels. Optimized for precision finishing and light profiling, the SGS38259 ensures minimal cusp height for superior surface finishes while maintaining tight tolerances on aerospace, automotive, and mold-making components.

ISO Designation Breakdown

The ANSI/ISO standard designation for this endmill decodes as follows:

Engineering Dimensions & Geometry

Grade Details – Key Grade Characteristics

The Micro-Grain Carbide substrate used in the SGS38259 is manufactured from ultra-fine tungsten carbide particles (0.5–0.8 μm grain size) sintered with a cobalt binder. This micro-grain structure delivers:

• Transverse Rupture Strength: >4,200 MPa – resists chipping in interrupted cuts
• Hardness: 92.0 HRA – maintains edge integrity at elevated cutting temperatures
• Young's Modulus: ~600 GPa – minimizes deflection in long-reach applications
• Thermal Conductivity: 80 W/m·K – efficient heat dissipation from the cutting edge

The uncoated substrate maintains a razor-sharp edge with no coating-induced edge rounding, making it ideal for aluminum, brass, and thermoplastics where built-up edge must be minimized.

Grade Comparison Matrix

Chipbreaker Profile

The SGS38259 incorporates an advanced Fine-Finish Profile two-flute geometry that maximizes chip pocket volume and governs chip formation and evacuation:

• Flute Form: Wide-core parabolic flute with 30° helix angle and deep gash geometry promotes rapid chip evacuation and reduces chatter in deep-pocket milling. The two-flute design provides approximately 40% more chip pocket volume than a comparable four-flute tool.
• Gash Land: Precision-ground gash land behind the primary relief face creates a secondary cutting edge that slices chips into manageable curls, preventing recutting and heat buildup.
• Edge Preparation: Sharp ground edge (0.005" hone) for minimal cutting force and clean shear.
• Corner Geometry: The 0.015R radius is blended with a tangential transition into the flute wall, eliminating stress concentrators and distributing cutting forces evenly across the corner.

Recommended Applications & Workpiece Materials

Application Map by Operation

Recommended Cutting Conditions

Parameters below are starting recommendations for stable setups with minimum 2×D gauge length projection. Adjust based on machine rigidity and coolant delivery.

Note: Values assume flood coolant or through-spindle coolant (TSC) delivery. Reduce speeds 20% for dry machining of steels. Always verify stability with a test cut.

Operating Guidelines

• Runout Check: Verify toolholder TIR is ≤0.0003" (7.6 μm) at the tool tip. Excessive runout will unevenly load flutes and cause premature corner failure.
• Engagement Strategy: For slotting, use a helical entry ramp at 2–3° inclination rather than straight plunging to minimize axial shock on the corner radius.
• Stepover Recommendation: For finishing, set radial stepover (ae) to 5–8% of diameter for 0.015R tools to achieve Ra 0.4–0.8 μm surface finish.
• Coolant Protocol: Use air blast or mist for aluminum to prevent chip welding. For steels, flood coolant is recommended to control heat.
• Chip Evacuation: The two-flute design provides excellent chip clearance; however, in deep slots (>2×D), use compressed air or through-spindle coolant to ensure chips do not recirculate.
• Tool Life Indicator: Monitor flank wear (VB) on the primary relief. Regrind or replace when VB reaches 0.008" (0.2 mm) or when surface finish degrades beyond specification.
• Storage: Store in original protective packaging away from corrosive atmospheres. Carbide is brittle—avoid dropping or impacting against hard surfaces.

Toolholder Compatibility

The SGS38259 is designed for use in standard endmill holders and collet chucks conforming to ANSI B94.19 and DIN 1835 standards:

• Endmill Holders (Weldon): Direct fit in Weldon-style holders with set-screw engagement on the flat. Ensure set-screw torque is 8–12 N·m.
• ER Collet Chucks: Compatible with ER25, ER32, and ER40 collets (select based on shank diameter). Grip length should be ≥2.5× shank diameter for stability.
• Hydraulic Chucks: Excellent for high-speed finishing. Provides 360° uniform clamping and minimizes runout to <0.0002".
• Shrink-Fit Holders: Not recommended for Weldon-flat shanks due to interference with the flat land. Use cylindrical-shank variants for shrink-fit applications.
• Pull-Stud / Retention Knob: Ensure CAT40/CAT50 or BT30/BT40 pull-stud torque is correct per machine manual to prevent holder loosening during aggressive cuts.

Packaging & Ordering Information

• Individual Packaging: Each endmill is supplied in a rigid plastic tube with end caps to protect cutting edges during transit and storage.
• Labeling: Tube label includes Kyocera part number (SGS38259), batch code, manufacturing date, and barcode for inventory tracking.
• Minimum Order Quantity: 1 piece. Bulk pricing available for quantities of 10, 50, and 100+.
• Lead Time: In-stock items ship within 1–2 business days. Non-stock sizes may require 4–6 weeks manufacturing lead time.
• Regrinding Service: Kyocera authorized service centers offer regrind and re-coating programs. Contact Kyotow.com support for regrind pricing and turnaround.

Catalog Meta Data