TAP-FLEX^®

Specifications THREAD VERSION UNC threaded bolt ANCHOR MATERIALS Carbon steel with Stalgard® PLUS coating HEAD STYLES Hex Washer Head ANCHORE SIZE RANGE 3/8" through 5/8" diameters SUTABLE BASE MATERIALS Steel Aluminum

Thread-Forming Structural Screws 

Elco Tap-Flex have transitioned to Dewalt Tap-Flex
You can review the Elco Tap-Flex Spec Sheet that is being phased out here
Specs on this page are utilizing technical information from the new DEWALT Tap-Flex Tech Page

Tap-Flex^® Thread-Forming Structural Screws are thread-forming, dual heat treated self-tapping fasteners that provide the strength, ductlity, and resistance to embrittlement failures required in critical curtain wall and dissimilar metal applications. Tap-Flex fasteners are designed to offer a replacement option for traditional nut and bolt assemblies. These fasteners provide an excellent solution for blind connections. The patented E-Form^® segmented thread profile design improves installation and forms threads that provide increased thread engagement.

GENERAL APPLICATIONS AND USES 

• Curtain walls
• Hollow Steel Sections (HSS)
• Window walls/Glazing
• Curtain wall/Cladding
• Angles and brackets
• Metal Infill Panels
• Stairs and risers

FEATURES AND BENEFITS  

• Eliminates thread-tapping operations and allows for blind installations (e.g. HSS)
• High hardness lead threads for tapping into steel and aluminum
• E-Form^® thread profile overcomes friction build-up and reduces drive torque +Formed threads help resist loosening (e.g., vibration, thermal change)
• Serrations on underside of hex washer head lock against the fixture
• In the load-bearing area, a lower hardness heat treatment provides Grade 5 bolt mechanical properties, resulting in a fastener with increased ductility having no significant susceptibility to Hydrogen-Assisted Stress Corrosion Cracking (HASCC)
• Stalgard^® Plus Coating provides improved corrosion resistance as well as enhanced galvanic compatibility in dissimilar metal applications, including those involving aluminum, compared with fasteners with standard zinc plating
• Fasteners coated with Stalgard PLUS typically show no red rust or other base metal corrosion on significant surfaces after 1500 hours of salt spray exposure in accordance with ASTM b117
• Fasteners accept standard nuts and washers (if desired and/or required)

APPROVALS AND LISTINGS

• Pull-out testing conducted in accordance with AISI S905 using the alternate tension test (with adjustments to allow for large fastener diameters)
• Shear testing conducted in accordance with AISI S905 using the standard lap joint shear test (with adjustments to allow for large fastener diameters)

GUIDE SPECIFICATIONS

05 05 23 – Metal Fastenings, 09 22 16.23 – Fasteners. Fasteners shall be Tap-Flex as supplied by DEwALT, Towson, MD. Fasteners shall be installed in accordance with published instructions and the Authority Having Jurisdiction.

MATERIAL SPECIFICATIONS

Fastener Component	Specification
Fastener body	Medium carbon steel
Plating/Coating	Stalgard PLUS coating 1,500 hour rating in for ASTM b117 salt spray test

INSTALLATION SPECIFICATIONS

Installation Specifications and Supplemental Information for Tap-Flex

Dimension	Unit	Fastener Diameter
		3/8"	1/2"	5/8"
Thread Size (UNC)	in.	3/8-16	1/2-13	5/8-11
Nominal drill bit diameter	-	8.5 mm	29/64"	37/64"
Impact wrench socket size	in.	9/16	3/4	15/16
Head height1	in.	3/8	1/2	19/32
washer diameter	in.	3/4	1	1-1/4
Maximum material thickness (Tapping)	in.	5/8	3/4	1
Effective tensile stress area (Threads)	in2	0.078	0.142	0.226
Effective tensile stress area (Unthreaded Shank)	in2	0.086	0.156	0.249
Minimum specified ultimate strength	ksi	120	120	120
Minimum specified yield strength	ksi	92	92	92
1. Head height includes the thickness of the integral washer.

 

Seating Torque of Tap-Flex Fasteners in Steel, ft-lbf1,2,3

Fastener Diameter	Steel Type and Thickness
	A653 Grade 33 / A500 Grade A (Fu = 45 ksi)						A36 / A500 Grade B (Fu = 58 ksi)						A572 Grade 50 (Fu = 65 ksi)
	1/8"	3/16"	1/4"	3/8"	1/2"	5/8"	1/8"	3/16"	1/4"	3/8"	1/2"	5/8"	1/8"	3/16"	1/4"	3/8"	1/2"	5/8"
3/8"	13	25	35	36	-	-	16	32	40	40	-	-	18	36	40	40	-	-
1/2"	13	26	33	56	95	-	17	34	43	72	95	-	19	38	48	80	95	-
5/8"	16	32	47	88	118	185	21	41	60	114	152	185	23	46	67	128	171	185
Tabulated seating torques are 75% of the tested ultimate failure torque in each material. Tabulated seating torques are based on laboratory testing and are for reference only. If seating torques greater than snug tight are desired, it is suggested to determine the failure torque in the application and base material with a manual torque wrench. Maximum seating torque should not exceed 75% of this failure torque. when using a washer under the head of the fastener, multiply tabulated seating torques by 0.75.

 

Seating Torque of Tap-Flex Fasteners in Aluminum, ft-lbf1,2,3

Fastener Diameter	Aluminum Type and Thickness
	6063-T5 (Fu = 22 ksi)			6063-T6 (Fu = 30 ksi)			6061-T6 (Fu = 38 ksi)
	1/8"	3/16"	1/4"	1/8"	3/16"	1/4"	1/8"	3/16"	1/4"
3/8"	11	23	31	14	30	39	17	36	40
1/2"	11	22	32	15	27	44	18	32	56
5/8"	14	29	49	20	38	59	25	47	70
Tabulated seating torques are 75% of the tested ultimate failure torque in each material. Tabulated seating torques are based on laboratory testing and are for reference only. If seating torques greater than snug tight are desired, it is suggested to determine the failure torque in the application and base material with a manual torque wrench. Maximum seating torque should not exceed 75% of this failure torque. when using a washer under the head of the fastener, multiply tabulated seating torques by 0.75.

TECHNICAL GUIDE – SCREW FASTENERS ©2022 DEWALT – REV. b

 

Suggested Minimum Spacing and Edge Distance of Tap-Flex Fasteners1

Fastener Diameter d (in.)	Minimum Screw Spacing in Aluminum 2.5d (in.)	Minimum Screw Spacing in Steel 3d (in.)	Minimum Edge Distance in Aluminum and Steel 1.5d (in.)
3/8	15/16	1-1/8	9/16
1/2	1-1/4	1-1/2	3/4
5/8	1-9/16	1-7/8	15/16
1. Fastener spacing is measured center-to-center and fastener edge distance is measured center-to-edge.