Self-Drilling Screw Selection Guide
Choosing the right self-drilling screw depends on the material being fastened, the thickness of the substrate, the required corrosion resistance, and the load the connection needs to carry. This guide explains how self-drilling screws work, when to use structural or stainless options, how to choose the right point size, and which fastener types are best for steel-to-steel, aluminum-to-steel, aluminum-to-aluminum, and wood-to-steel applications.
How to Choose the Right Self-Drilling Screw
Start by identifying the materials you need to join. Self-drilling screws are commonly used for steel-to-steel, aluminum-to-steel, aluminum-to-aluminum, and wood-to-steel fastening. From there, choose a screw based on four main factors: drill point capacity, material compatibility, corrosion resistance, and head style.
Drill point size matters because each point is designed for a specific material thickness range. If the point is too small for the base material, installation becomes slower and less reliable. If the screw is oversized for the job, you may be paying for performance you do not need.
Material and finish also matter. Carbon steel and structural self-drilling screws are often used when strength is the top priority. Stainless and bi-metal fasteners are better choices when corrosion resistance is critical, especially in aluminum, exterior, coastal, or high-moisture environments.
Head style should match the application. Hex washer heads are common for metal building and roofing work, while low-profile, flat, wafer, or pancake heads may be preferred where clearance, appearance, or clip attachment matters.
Self-Drilling Screw Selection Guide: Types, Materials, Point Sizes & Applications
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 Dril-Flex® Dril-Flex Structural Drill Screws are dual heat-treated self-drilling tapping screws that provide the strength, ductility and resistance to embrittlement required for critical applications. |
 Bi-Flex® Bi-Flex structural screws are bi-metal self-drilling tapping screws that provide the corrosion resistance of 300 series stainless steel and theH53 efficiency of drill screws. Bi-Flex screws are suitable for use in both steel and aluminum. |
 Alumi-Flex® Alumi-Flex structural drill screws are 300 series (18-8) stainless steel self-drilling tapping screws that are used for fastening to aluminum when corrosion resistance and galvanic reaction are a primary concern. |
 Drillit® Drilit® self drilling fasteners (often called Tek Screws) are designed for faster, easier & more economical installations by eliminating dual process functions of drilling and tappin. |
 ITW Teks Select™ Designed to attach similar or dissimilar metals, Teks Select fasteners have strength and ductility performance similar to Grade 5 bolts. These characteristics in the fastener’s load-bearing area improve resistance to shear failure due to wind and other loads requiring mechanical flex (ductility). |
 ITW Teks Self drilling screws are offered in sharp and drill points that easily penetrate light to heavy gauge metal and wood. With ITW Teks Self drilling screws professionals can drill, tap, and fasten – all in one motion. |
 Structural Grade 5 Tanner Grade 5 drill screws are made from alloy steel heat treated to Grade 5 specifications, SAE J429 (ASTM A449 Type 1) (RC 28-34), with a higher hardness on the drill point and lead threads (RC 52 min) and coated with a 1,000 hours salt spray corrosion-resistant coating. |
 Architectural Roof Clip Fasteners ELCO Architectural Roof Clip Fasteners offer a low-profile head design for wood and steel applications. The efficiency of self-drilling fasteners and the aesthetics of an unobtrusive head are ideal for attaching metal roof clips to metal and wood. |
 EJOT® Marine Grade Stainless Steel Marine Grade 316 Stainless Steel and provide exceptional corrosion protection and superior ductility. The JT6 Bi-Metal Self-Drilling Fasteners feature a screw head and threads that are made of 316 stainless steel & a drill point made of hardened carbon steel that is welded to the body. |
Self-Drilling Screws Manufactured in the USA by a Tanner Approved Vendor. These screws are heat treated in strict accordance to SAE J78 and feature a coating that provides 1000 hours of salt spray protection. |
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| Features | ||||||||||
| Structural Self Drilling | YES | YES |
YES Immune to hydrogen assisted stress corrosion cracking |
NO | YES |
NO | YES |
NO |
NO |
NO |
| Critical Applications | YES | YES | NO | NO | YES |
NO | YES | NO | NO | NO |
| Made in USA | YES | NO |
NO |
NO | YES |
VARIOUS | YES |
NO | NO | YES |
| ICC Approved | YES | YES | YES | YES | YES | YES | NO | YES | FM APPROVED | NO |
| Corrosion Resistant Finish | Silver Stalgard® (PWH, PUFH) or Stalgard SUB coating (HWH, PPH) | Stalgard® GB |
Stalgard® GB |
Stalgard®, Gray Stalgard® & Zinc | Climaseal® ACR |
Climaseal®, Climaseal® ACR, Climacoat® , Gray Spex, Zinc Electro | Corrosion Resistant | Stalgard® Silver |
N/A | YES |
| Salt Spray Preformance | Silver Stalgard® (1000 hours) or Stalgard SUB (2000 hours) | 1,000 Hrs. | 1,000 Hrs. | 1,000 Hrs. | 1,000 Hrs. | Climasea® , Climaseal® ACR (1000 hrs.), Climacoat® (500 hrs.) , Gray Spex (300 hrs.), Electro Zinc (48 hrs.) | 1,000 Hrs. | 1,000 Hrs. | N/A | 1,000 Hrs. |
| Material | Medium Carbon Steel | Stainless (300) |
Stainless (300) 18-8 | Case Hardened Carbon Steel |
Medium carbon steel | Steel | Alloy Steel | Case Hardened Steel | 316 Stainless Steel | Case Hardened Carbon Steel |
| Tanner Base Code | *EAF,*EDX & EBL | *EAJ,*EAX & EBN | *EAH, & EBM | EDO, EDA, EHL, EDC, ECC, ECW, EHB, EDM & EDT | ITW | ITW | UHW5C/USA & UFP5C/USA | EDO | JT6 | UHW3TC, UHHW3TC, UHHWB3TC, UHW3STCB, UHW4TC, UHW5TC, UHWB4TC, UHWB5TC |
| Material Note | Dual Hardened - Load Bearing Area meets SAE J429 Grade 5 and ASTM A449 Type 1 specifications |
Hardened Steel Tapping Threads and Point Fused onto an 18-8 Stainless Steel Shank and Head |
Case Hardened Carbon Steel | Strength and ductility performance similar to a Grade 5 SAE J 429 and ASTM A 449 fastener | Case Hardened Carbon Steel | Alloy steel heat treated to Grade 5 specifications, SAE J429 (ASTM A449 Type 1) (RC 28-34) | A4 stainless steel body, case hardened carbon steel drill point | Heat treated in strict accordance to SAE J78 | ||
Technical Specs |
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| Washer | NO | NO |
NO |
YES Bonded Sealing, Integral Sealing System |
NO |
YES Bonded Sealing, Integral Sealing System |
NO |
NO |
YES Stainless-steel/EPDM vulcanized sealing washer vulcanized sealing washer |
YES Galvanized bonded washers |
| Head Styles | Hex Washer Head; Pan Head; Wafer Head, Undercut Flat Head | Hex Washer, Pan, Pancake, Flat, Flat UC |
Hex Washer, Undercut Flat |
Hex Washer, Pan, Wafer & Flat |
Hex Washer Head (HWH) |
Hex Washer Head, HWH w/serrations, Pan Head | Hex Washer & Flat UC |
Pancake |
Hex Washer, Hex w/ Sealing Washer, Button, Flat Ctsk | Hi-Hex Washer, Hex Washer |
| Drive Styles | Hex and Phillips | Hex and Phillips |
Hex and Phillips |
Hex and Phillips |
Hex (Unslotted) |
Hex (Unslotted), Phillips, Combo (Sq/Ph) | Hex and Phillips |
Phillips |
Hex and Torx® | Hex |
| Point Sizes | #3, #4 & #5 | #2, #3, #4 & #5 |
#3 & #4 |
#1, #2, #3, #4, #4.5 & #5 |
# 3 & #4 |
#1, #2, # 3, #4, #4.5 & #5 | #3, #4 & #5 |
#3 |
#1, #2, #3, #5 | #1 Point Stitch, #3, #4, #4.5 & #5 |
| Diameters | #10, #12, 1/4" & 5/16" | #10 to 1/4" |
#10 to 1/4" |
#6, #8, #10, #12, 1/4" & 5/16" |
#10, #12, #14 & 1/4"-20 | #10, #12, #14, 12-24 & 1/4"-28 | #10, #12, #14, 12-24 & 1/4"-20 |
#10 & #12 |
#10 & #12 | #10, #12, #14, 12-24, 1/4"-20 |
| Lengths | 3/4" to 4" | 3/4" to 8" | 3/4" to 8" | 3/8" to 4" | 3/4 to 2" | 1/2” to 8” | 3/4" to 3-3/8" | 1" to 2” | 3/4" to 1-3/8" | 3/4"to 6" |
| Technical Specifcation Download | DOWNLOAD | DOWNLOAD | DOWNLOAD | DOWNLOAD | DOWNLOAD | DOWNLOAD | DOWNLOAD | DOWNLOAD | DOWNLOAD | BY REQUEST |
Application |
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| Steel-to-Steel | YES | YES | NO | YES | YES |
YES | YES |
YES |
YES | YES |
| Aluminum-to-Steel | YES | YES | NO | NO | YES | NO | YES | NO | YES | NO |
| Aluminum-to-Aluminum | YES | YES | YES | NO | YES | NO | YES | NO | NO | YES |
| Wood-to-Steel | YES | YES | NO | YES | YES |
YES | YES |
YES |
NO | NO |
| Misc Building Materials to Aluminum |
NO | NO | YES | NO | NO |
NO | NO | NO |
NO | NO |
| Composite Material-to-Steel | NO | NO | NO | YES | NO | NO | NO | NO | NO | YES |
| Curtain walls , Rainscreen , Window walls/glazing, Solar panel systems | Steel-to-steel connections , Aluminum-to-steel connections, Aluminum-to-aluminum connections, Wood-to-steel connections | Aluminum-to-aluminum connections ,Attaching misc. building materials to aluminum | Steel-to-steel connections, Wood-to-steel connections, Composite material-to-steel connections | Metal attachments, including aluminum to steel | Light, medium, heavy duty steel-to-steel, wood-to metal, metal roof and wall | Curtain walls , Rainscreen , Window walls/glazing, Solar panel systems | Low-profile head design for wood and steel applications. | For applications that require exceptional corrsion resistance and superior ductility | Steel-to-steel, aluminum-to-aluminum | |
Reference Articles Related to Self-Drilling Screws
Self-Drilling Screws – How They Work
Self-Drilling Screws eliminate the need for separate drilling and tapping operations, helping provide the user with a faster, more economical installation process.
When selecting our screw size and length remember to take into consideration of the total thickness of the material including the gap between the two pieces being joined.
Screw point is the first part of the screw to make contact with material. Screw points are categorized into (5) major product groups, with each group having a number of different screw points available.
Self-Drilling Screws operate on the same principles as drill bits and other cutting tools. This means that the way in which these screws are used affects their performance as much as how they are designed.