Self-Drilling Screws Guide (Tek Screws)
Complete guide to self-drilling screws including Tek point types, metal thickness applications, thread designs, and installation techniques for HVAC, roofing, and metal framing projects.
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Self-Drilling Screw Point Types
Self-drilling screws (commonly called Tek screws after the brand name) feature a drill point that penetrates metal without pre-drilling, significantly reducing installation time. The point type must be matched to the combined thickness of materials being joined to ensure the drill point fully penetrates before threads engage.
How Self-Drilling Screws Work
Self-drilling screws combine drilling and fastening in one operation:
- Drill point penetrates through metal like a drill bit
- Flutes remove chips as point drills through material
- Threads engage after point emerges on opposite side
- Self-tapping action forms mating threads in metal
- Faster installation than pre-drilling + standard screws
- Consistent holes - no wandering or misalignment
Tek Point Types by Material Thickness
Tek 1 (Shortest Point)
Entry-level drill point for the thinnest materials. Limited penetration capacity.
- Drill point length: 0.016" to 0.031"
- Maximum thickness: 0.035" to 0.060" (29-20 gauge)
- Sharp drill point
- Very short flutes
- Fast drilling action
- Best for: Thin sheet metal, HVAC ductwork, light metal panels
Tek 2
Most common type for light to medium gauge metal applications.
- Drill point length: 0.050" to 0.070"
- Maximum thickness: 0.060" to 0.090" (18-14 gauge)
- Medium-length point
- Good chip clearance
- Versatile for many applications
- Best for: Metal studs, light structural steel, roofing, standard HVAC
Tek 3
Medium-duty point for standard steel framing and structural applications.
- Drill point length: 0.115" to 0.130"
- Maximum thickness: 0.090" to 0.190" (11-7 gauge)
- Longer drill point
- Enhanced flute design
- Industry standard for commercial
- Best for: Steel studs, metal framing, structural connections, commercial roofing
Tek 4
Heavy-duty point for thick steel and structural steel applications.
- Drill point length: 0.190" to 0.200"
- Maximum thickness: 0.190" to 0.250" (7-3 gauge)
- Long drill point
- Deep flutes for chip removal
- Hardened point for durability
- Best for: Heavy structural steel, thick metal decking, industrial applications
Tek 5 (Longest Point)
Maximum penetration capacity for the thickest metal applications.
- Drill point length: 0.250" to 0.315"
- Maximum thickness: 0.250" to 0.500" (up to 1/2" thick)
- Extra-long drill point
- Maximum chip clearance
- Requires high torque tools
- Best for: Thick structural steel, heavy equipment, industrial machinery
Stitch Screws (Specialty)
Short point designed specifically for joining two layers of thin metal together.
- Very short drill point
- Metal-to-metal stitching
- No pilot hole needed
- Self-tapping threads
- Common in HVAC assembly
- Best for: Ductwork seams, metal panel overlaps, thin metal joining
Download Tek Point Selection Guide
Print reference showing point types matched to material thicknesses
Point Selection GuideCritical: Point Selection Mistakes
- Point too short: Won't penetrate fully - threads engage before point emerges, causing binding and breakage
- Point too long: Works but costs more - wastes money on unnecessary drill length
- Combined thickness matters: Add ALL metal layers together when selecting point type
- Always round up: If between two point types, choose the longer one for safety
- Hardened steel: May require Tek 4 or 5 even for thinner materials
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Shop All Tek Screws Ask an ExpertApplications & Thread Types
Self-drilling screws are available with different thread designs to optimize performance for specific materials and applications. Matching the thread type to your application ensures maximum holding power and installation efficiency.
Thread Designs for Different Applications
Fine Thread (Type S)
Close-spaced threads designed specifically for sheet metal applications.
- 20-24 threads per inch
- Maximum thread engagement
- Best for thin to medium gauge metal
- Standard for HVAC and roofing
- High pull-out resistance
- Applications: Metal studs, ductwork, metal roofing, thin steel
Coarse Thread (Type W)
Wide-spaced threads for attaching metal to wood or composite materials.
- 6-12 threads per inch
- Designed for wood fiber grip
- Faster installation than fine thread
- Metal panel to wood substrate
- Common in construction
- Applications: Metal roofing to wood, siding to studs, steel to lumber
Hi-Lo Thread (Dual Thread)
Combination of high and low threads for universal applications and faster driving.
- Alternating thread heights
- Works in metal and wood
- Reduced driving torque
- Less material deformation
- Versatile for mixed materials
- Applications: Metal to wood, plastics, composites, multi-material assemblies
Thread Cutting (Type 17, 23)
Thread-cutting design that removes material rather than forming threads.
- Sharp cutting edges on threads
- Reduces installation torque
- Better for brittle materials
- Less stress on material
- Ideal for thick or hard metals
- Applications: Stainless steel, thick steel, cast metals, hard alloys
Industry-Specific Applications
HVAC & Ductwork
- Point type: Tek 1 or 2 for thin gauge
- Thread: Fine thread (Type S)
- Common sizes: #8 × 1/2", #10 × 3/4"
- Head style: Hex washer or pan head
- Material: Zinc plated or stainless
- Tip: Use stitch screws for seam joining
Metal Roofing
- Point type: Tek 3 for standard, Tek 4 for heavy
- Thread: Coarse for wood, fine for metal
- Common sizes: #12 × 1-1/2" to 3"
- Head style: Hex washer with EPDM seal
- Material: Painted or stainless steel
- Tip: Match screw color to panel
Metal Framing/Studs
- Point type: Tek 2 or 3 for 20-18 gauge
- Thread: Fine thread (Type S)
- Common sizes: #8 × 1/2", #10 × 1"
- Head style: Pan head or wafer head
- Material: Black phosphate or zinc
- Tip: Use framing guns for speed
Metal Decking
- Point type: Tek 4 or 5 for structural
- Thread: Fine thread, high strength
- Common sizes: #12 to 5/16" × 1" to 3"
- Head style: Hex washer for torque
- Material: Heat-treated, zinc plated
- Tip: Follow deck manufacturer specs
Metal Siding
- Point type: Tek 2 or 3 depending on backing
- Thread: Coarse for wood, fine for metal
- Common sizes: #10 × 1-1/4" to 2"
- Head style: Painted match head
- Material: Color-matched coating
- Tip: Use washer for weatherproofing
Structural Steel
- Point type: Tek 4 or 5 for thick steel
- Thread: Thread cutting (Type 17)
- Common sizes: 1/4" to 3/8" diameter
- Head style: Hex head for high torque
- Material: Hardened, galvanized
- Tip: Pre-mark hole locations
Download Application Guide
Print guide showing recommended point and thread types by application
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Browse by Application Request QuoteSelf-Drilling Screw Size Chart
Self-drilling screws are available in a wide range of sizes from small #6 HVAC screws to large 5/16" structural fasteners. Selection depends on material thickness, application requirements, and load demands.
| Size | Gauge/Diameter | Common Lengths | Typical Point | Primary Applications |
|---|---|---|---|---|
| #6 | 6 gauge (0.138") | 1/2", 3/4", 1" | Tek 1, Tek 2 | Light HVAC, thin ductwork, metal panels |
| #8 | 8 gauge (0.164") | 1/2", 3/4", 1", 1-1/4" | Tek 2 | HVAC, light metal framing, ductwork |
| #10 | 10 gauge (0.190") | 3/4", 1", 1-1/2", 2" | Tek 2, Tek 3 | Metal studs, standard roofing, HVAC |
| #12 | 12 gauge (0.216") | 1", 1-1/2", 2", 3" | Tek 3, Tek 4 | Metal roofing, framing, structural light |
| #14 | 14 gauge (0.242") | 1-1/2", 2", 2-1/2", 3" | Tek 3, Tek 4 | Heavy roofing, metal siding, structural |
| 1/4" | 1/4" diameter | 1-1/2", 2", 3", 4" | Tek 4, Tek 5 | Structural steel, thick metal, heavy-duty |
| 5/16" | 5/16" diameter | 2", 3", 4", 6" | Tek 5 | Heavy structural, equipment mounting |
Size Selection Guidelines
- Diameter selection: Based on required holding strength and material thickness
- Length selection: Must penetrate through all layers plus minimum 3/8" engagement
- HVAC standard: #8 × 1/2" to 3/4" most common for ductwork
- Roofing standard: #12 × 1" to 2" typical for metal-to-wood
- Framing standard: #10 × 1" typical for metal stud to track
- Structural: 1/4" and larger for load-bearing connections
- Minimum engagement: At least 3 full threads into base material required
Head Styles & Features
Hex Washer Head
Most common for exterior and roofing applications.
- Integrated washer provides seal
- Hex drive for high torque
- Often includes EPDM washer
- Weatherproof design
- Available in multiple colors
- Use for: Roofing, siding, exterior applications
Pan Head
Low profile head for tight spaces and interior work.
- Phillips or square drive
- Smooth finished appearance
- Lower profile than hex washer
- Good for interior applications
- Easy to paint over
- Use for: HVAC, metal framing, interior work
Hex Head (No Washer)
Heavy-duty applications requiring maximum torque.
- No integrated washer
- Maximum torque capacity
- Structural applications
- Separate washers available
- Socket drive for impact tools
- Use for: Structural steel, heavy equipment
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Shop All Sizes Ask an ExpertInstallation Best Practices
Proper installation of self-drilling screws requires correct drill speed, adequate torque, and proper technique to ensure the drill point penetrates cleanly and threads engage fully. Following these guidelines prevents common failures like stripped heads, broken points, and inadequate holding power.
Tool Selection & Setup
Power Tools
- Impact driver: Best for #8 and smaller screws
- Drill/driver: Good for controlled speed, clutch setting
- Screw gun: Professional option for high-volume work
- Magnetic sockets: Required for hex head screws
- Bit holders: Magnetic holders prevent screw wobble
- Collated system: Auto-feed for production work
Speed & Torque Settings
- Start speed: Medium (1500-2000 RPM) to establish hole
- Drilling phase: Full speed once point engages
- Threading phase: Reduce speed as threads engage
- Too fast: Overheats point, damages threads
- Too slow: Point won't cut, causes binding
- Torque: Set clutch to stop when seated (avoid over-tightening)
Installation Technique
Starting the Screw
- Hold drill perpendicular to surface
- Apply firm, steady pressure
- Start at medium speed
- Let point establish position (1-2 seconds)
- Don't force or push too hard
- Keep bit centered on screw head
Drilling Phase
- Increase to full drill speed
- Maintain steady pressure
- Watch for chips clearing flutes
- Listen for point breakthrough
- Don't hesitate mid-drilling
- Point must fully penetrate first layer
Threading & Seating
- Reduce speed as threads engage
- Maintain constant pressure
- Stop when washer compresses
- Don't over-tighten (strips metal)
- Check for tight connection
- Verify no gap between materials
Common Installation Problems & Solutions
- Point breaks: Point too short for thickness OR too much pressure - select longer point, reduce pressure
- Screw spins/won't grip: Point didn't fully penetrate - use longer point type or pre-drill
- Stripped drive: Wrong bit size OR worn bit - use correct size, replace worn bits frequently
- Material tears: Drill speed too slow OR point dull - increase speed, replace screws
- Screws overheat: Speed too high OR inadequate chip clearance - reduce speed slightly
- Won't start: Drill wandering on smooth surface - use center punch or pilot dimple
Quality & Safety Checks
During Installation
- Verify screw is perpendicular
- Listen for clean drilling sound
- Watch for metal chips clearing
- Feel for thread engagement
- Check that washer is compressing evenly
- Ensure no gaps between materials
After Installation
- Check fastener is tight (no wobble)
- Verify washer is compressed (if equipped)
- Look for stripped heads or damage
- Check for material deformation
- Ensure no proud screws (roofing)
- Test pull strength on sample joints
Pro Installation Tips
- Practice first: Test technique on scrap material before starting project
- Fresh bits: Replace bits every 500-1000 screws for consistent performance
- Mark locations: Pre-mark screw positions for straight lines and consistent spacing
- Temperature matters: Cold weather makes metal more brittle - adjust technique
- Lubrication: For stainless or hardened steel, use cutting fluid on point
- Backup material: Use backer plate for thin materials to prevent tearing
- Safety: Wear eye protection - metal chips fly during drilling
Download Installation Guide
Step-by-step instructions with troubleshooting and speed recommendations
Installation GuideQuestions About Your Installation?
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