SPAX® PowerLags® T-Star Washer Head, Interior Construction Screws, Yellow Zinc

Base Part #: 458102()

Choose SPAX T-Star Washer Head Interior Construction PowerLag Screws. The low-profile, large-diameter design provides outstanding clamping force and improved aesthetics. Deep T-Star drive offers excellent bit engagement without requiring a “special” driver bit. Available in 1/4”, 5/16”, and 3/8” diameters and in lengths up to 10”. Yellow zinc coating for use in interior structural applications. Buy SPAX T-Star Washer Head PowerLags and interior construction screws in bulk pails or in job-friendly package quantities (hex driver included) from wholesalers, dealers, and specialty distributors or retail hardware and home improvement stores near you.


SPAX® T-Star Washer Head construction fasteners with yellow zinc coating are intended for interior structural wood-to-wood connection applications. These fasteners are designed with a low profile large diameter wafer head for applications requiring additional surface area under the head for superior pull-down force. Ideal for framing attachment and multi-ply beam applications. 

Materials & Coating

Cold-rolled “carbon steel” wire, heat treated to grade 5 durability and plated with a yellow zinc finish to prevent red rust. “Yellow zinc” is tested and recognized for use in above ground contact pressure treated lumber for interior dry/damp general construction applications (e.g. AWPA UC1-UC2).


SPAX PowerLags with built-on washer design is available in a variety of screw styles, including Hex head, T-Star, and multiple coating options. Our interior and exterior construction screws require no pre-drilling and drive faster and easier than conventional lags and other structural lag screws. We offer the largest selection of code-recognized structural wood-to-wood fasteners in the industry.

  • IRC / IBC Code Compliant DrJ TER No. 1912-07 Structural Fastener Properties
  • DrJ Technical Evaluation Report (TER No. 1802-03; Multi-Ply; Sawn lumber assemblies and engineered wood - LVL, PSL and LSL assemblies) 
  • Grade 5 durability
  • No pre-drilling required (1/4" and 5/16")
    Note: Lead holes of 11/64" (0.172") diameter are required for 3/8"
  • Patented thread serrations require up to 40% less driving torque to increase installation speed while helping prevent cracking in logs
  • Built-on washer head designs eliminate the need and extra cost of a separate washer 
  • Fastener length stamp on the head provides convenient identification without measuring and aids on-site inspections

Choose SPAX PowerLags structural wood to wood screws for interior and exterior applications. Request a sample pack of SPAX PowerLags today and build strong connections on the job site. Need something stronger? Shop our PowerLags collection designed for timber frame and log home construction.


• Multi-ply engineered wood (LVL, PSL, LSL) assemblies

• Multi-ply sawn lumber assembly

• Interior framing applications

• Shelving applications — interior buildings

• Indoor furniture

For CAD documents, please see Technical Documents.

SizeDrive/Bit SizeThreadAvailable Pkg. Options
Retail PaxLarge Retail Pax1 lb. Box3 lb. Box5 lb. BoxIndividualProject PaxContractor PaxMini PailBulk Pail
1/4" x 2-1/2"T-30Partial1+1250500
1/4" x 3"T-30Partial1+1250500
1/4" x 3-1/2"T-30Partial1+1250500
1/4" x 4"T-30Partial1+1250500
1/4" x 4-1/2"T-30Partial1+1250500
1/4" x 5"T-30Partial1+1250500
1/4" x 6"T-30Partial1+1250500
5/16" x 3"T-40Partial1+1250250
5/16" x 3-1/2"T-40Partial1+50250
5/16" x 4"T-40Partial1+1250250
5/16" x 4-1/2"T-40Partial1+50250
5/16" x 5"T-40Partial1+
5/16" x 6"T-40Partial1+
3/8" x 5"T-50Partial1+25150
3/8" x 6"T-50Partial1+1225150
3/8" x 8"T-50Partial150
3/8" x 10"T-50Partial1+150