Industrial DM 7/8UNF Ø20.5LF Thermal Friction Drill Bit
Precision Tungsten Carbide Thermal Drill Bit for High-Speed Chipless Tube & Plate Bushing Formation
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Features
Thermal Friction Flow Forming: Operates at 600°C+ to plasticize metal and extrude a strong threaded bushing in seconds.
Replaces Rivet & Weld Nuts: Creates a monolithic extruded boss with 3x the original sheet metal wall thickness.
Ultra-Hard Tungsten Carbide: Micro-grain solid carbide substrate provides extreme heat resistance and 10,000+ hole tool life.
Universal Thin-Wall Metal Forming: Optimally suited for carbon steel, stainless steel, aluminum tubing, and copper.
In-Depth Engineering Description & Technical Overview
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Overview of DM 7/8UNF Ø20.5LF Thermal Friction Drill Bit
The Industrial DM 7/8UNF Ø20.5LF Thermal Friction Drill Bit by DUOMI CNC is engineered for high-efficiency, chipless hole forming in thin-walled metal tubes, profiles, and sheet metal plates. Utilizing high rotational speed (typically 1,200–2,800 RPM) and axial force, the solid tungsten carbide bit generates localized frictional heat (600°C–800°C) to plasticize the workpiece metal. This creates a solid, high-strength bushing collar up to 3–5x the original wall thickness, perfectly sized for cold thread-forming to 7/8UNF specification.
The Ø20.5LF (Long Flat) design integrates a cutter collar that planes the surface smooth in a single operation, eliminating secondary deburring or facing processes.
Key Features & Technical Advantages
- Flat-Mouth (Planed Surface) Finishing: Long Flat (LF) geometry simultaneously forms the lower extrusion sleeve and planes off the top raised collar to create a perfectly flush surface.
- Zero-Chip Production: Chipless forming eliminates metal shavings, reducing waste disposal costs and protecting internal assemblies (e.g., fluid pipes, heat exchangers).
- High Tensile & Torsional Strength: Cold-formed thread bushings provide 3x higher pull-out torque compared to standard rivet nuts or sheet metal threads.
- Industrial Tungsten Carbide Construction: High thermal resistance and micro-grain carbide matrix yield extended tool life exceeding 3,000–5,000 holes per bit under optimal conditions.
- Universal CNC & Tapping Compatibility: Designed for standard CNC machining centers, high-speed drill presses, and automated thermal friction drilling units.
Guide to Thermal Friction Drill Bit Selection
When selecting thermal friction drill bits for production, understanding geometry options is critical:
- Standard Round-Mouth Type: Forms a lower extrusion sleeve while leaving a rounded rim/collar above the material surface. Best for applications where a raised face is acceptable or beneficial.
- Flat-Mouth (Planed/LF) Type: Features built-in cutting shoulders that shear away the top collar during the final downstroke, leaving a smooth, flat surface ideal for flush bolt seats and sealed joints.
Industry Applications & Compatibility
- Automotive & Transportation: Chassis frames, exhaust manifolds, fluid lines, and structural tubular assemblies.
- HVAC & Heat Exchangers: Multi-layer heat exchanger manifolds, central heating boilers, and liquid-cooling distribution pipes.
- Structural & Architectural Metalwork: Stainless steel furniture joints, balustrades, lighting support frames, and machinery guards.
- Aerospace & General Machinery: Lightweight structural frames requiring thread reinforcement without adding heavy weld nuts.
For complementary equipment, explore our range of CNC Drilling Machines and automated thermal tapping tooling.
Purchase & Delivery Guarantees
Direct Factory Assurance — Built, Tested, and Supported from Dongguan to Your Shop Floor
Runs on Your System
Standard GSK control (100% Fanuc G-code compatible) or optional Mitsubishi/Siemens. Direct CAD file import for code-free toolpath generation.
Factory Video FAT
Live drilling/tapping tests on your actual workpiece recorded before dispatch. Final 50% balance payment is paid only after your video approval.
40-Day Build & Rugged Crate
Guaranteed maximum 40-day manufacturing cycle. Sealed in anti-rust vacuum aluminum foil and bolted in fumigation-free timber crates (EXW/FOB/CIF).
Direct Engineer Care
Direct 1-on-1 WhatsApp group with your machine's build engineers, 12-month full warranty, and critical replacement parts dispatched via DHL within 24–48h.
Every DUOMI machine is built under a transparent 13-step factory production & responsibility chain.
Parameters
Download Technical Brochure| Thread Size | 7/8UNF |
| Diameter | Ø20.5 mm |
| Finishing | Plane Surface |
| Materials | Tungsten Carbide |
| Brand | DUOMI ( DM ) |
Machining Samples
Real parts processed by our machines
Frequently Asked Questions
We “only” do drilling & tapping. Why do customers still choose Duomi over general-purpose CNC machines?
What does “Your part defines the solution” mean in practice?
What is the primary benefit of the Ø20.5LF flat-mouth design over standard friction drill bits?
What thread size does the Ø20.5 mm thermal drill bit prepare?
Which metal materials are suitable for thermal friction drilling with this tool?
What operating parameters (RPM and feed rate) should be used?
Does thermal friction drilling require coolant during operation?
What is the expected tool life of a DUOMI tungsten carbide thermal drill bit?
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