When sourcing carbide rods, choosing between solid and coolant hole structures directly impacts heat dissipation, chip evacuation, and tool life. For industrial buyers, this is not just a structural difference—it defines the application.
Feature | Solid Rod | Coolant Hole Rod |
|---|---|---|
Structure | Fully solid, no internal holes. | Single straight, double straight, or 30° helical holes. |
Coolant Delivery | External flood cooling; slower heat dissipation. | High-pressure coolant直达 (direct-to-cutting-edge). |
Chip Evacuation | Moderate; long chips may re-cut. | Excellent; high-pressure coolant flushes chips away. |
Rigidity | Highest; maximum cross-sectional area. | Slightly lower (due to internal voids), but still far superior to HSS. |
Manufacturing Cost | Lower; simpler extrusion/CIP process. | Higher; complex internal hole forming required. |
Primary Applications | End mills, reamers, engraving bits, PCB micro-drills. | Deep-hole drills, gun drills, stainless/titanium alloy tools. |
Solid rods are the standard choice for general machining. With no internal cavities, they provide maximum cross-sectional area and torsional rigidity, making them ideal for high-feed side loading.
Best For: Profile milling, pocketing, shallow hole drilling (L/D < 5).
Key Advantage: Cost-effective; achieves peak Transverse Rupture Strength (TRS) for the grade.
Limitation: In deep-hole drilling, heat builds up rapidly, risking thermal softening ("burning" the edge).
Coolant hole rods are engineered for deep-hole drilling and heat-sensitive materials. They pump coolant exactly where it’s needed most—the cutting edge.
Single Straight Hole: Basic internal coolant; suitable for straight-flute drills and standard end mills.
Double Straight Hole: Higher coolant volume for large-diameter deep-hole drills (>Ø8 mm); balances cooling with rigidity.
Helical Hole (30°/40°): The premium choice for high-performance tools. Holes run parallel to the flute helix, ensuring continuous coolant coverage and optimal chip evacuation. Ideal for titanium, stainless steel, and high-temp alloys.
Best For: Deep-hole drilling (L/D > 5), gun drills, stainless steel/titanium/Inconel machining.
Key Advantage: Significantly extends tool life, improves hole straightness and surface finish, and allows higher cutting parameters.
Your Machining Requirement | Recommended Choice | Reason |
|---|---|---|
General steel/aluminum; L/D < 4 | Solid Rod | Most cost-effective; rigidity is sufficient. |
Deep-hole drilling (L/D > 5) | Coolant Hole Rod | Prevents chip packing and heat buildup. |
Stainless steel, Titanium, Inconel | Helical Coolant Hole Rod | Poor thermal conductivity requires high-pressure cooling to prevent work hardening. |
High surface finish requirements | Coolant Hole Rod | Prevents chip re-cutting and surface scoring. |
Budget-conscious standard tools | Solid Rod | Reduces raw material costs. |
Always define the hole structure explicitly to avoid ambiguity:
Solid: Ø6 x 330 mm (Solid)
Single Straight Hole: Ø6.3 x ID1.0 x 330 mm (Single Straight Hole)
Double Straight Hole: Ø8 x 2-Ø1.0 x 330 mm (Double Straight Hole)
Helical Hole: Ø10 x ID1.5 x 330 mm, 30° Helical (Helical Coolant Hole)
Quote based on drawings
Phone: 0731-28214800
tel: +86 17773379950
E-mail: sales@chinahardalloy.com