Trident Heat-Treated Carbon Steel Locknuts - Type SL - Unified -- SL-0420-1ZI
from PennEngineering

Type SL self-locking nuts are designed with a unique and economical TRI-DENT ® locking feature, which meets demanding locking performance requirements. 3 cycle locking performance. Achieved using steel socket head cap screws, 180 ksi / property class 12.9 with standard finish of thermal oxide... [See More]

  • Size: #4; 1/4"
  • Material: Hardened Steel
  • Type: TRI-DENT® Locking Feature
  • Finish: Zinc Plated
A 9M64-0440
from Stock Drive Products/Sterling Instrument - SDP/SI

Nylon Hex Lock Nut, #4-40 Self Threading, 0.25in. Head Height, 0.25in. Across Flats, Material - Nylon (Zytel 101). [See More]

  • Size: #4
  • Material: Plastic; Nylon
#4-40 K-Lock Nut, Zinc -- NG2KEP00440Z
from NBS Corp.

Featuring a built in external tooth lock washer for exceptional surface grip, NBS’ k-lock nuts are available from ¼” through ¾” internal diameter. All k-lock nuts are sourced from ISO-9001 accredited manufacturers and come with zinc finish. [See More]

  • Size: #4
  • Material: Steel
  • Type: Jet Nut (K-Nut)
  • Finish: Zinc Plated
Nylon Insert Locknut -- 4-40 NY - IN - LK - NU
from PENCOM

Custom sizes and other finishes available [See More]

  • Size: #4
  • Material: Steel (optional feature); Stainless Steel (optional feature)
  • Type: Nylon Insert Nut
  • Finish: Zinc Plated; Black Zinc