Cross Recessed Hex Head Three-Piece SEMS Bolts
Dual-Drive Hex Bolts with Captive Spring Lock Washer & Flat Washer
Cross Recessed Hex Head Three-Piece SEMS Bolts combine an indented external hexagon head with a centered cross recess, one captive single-coil spring washer and one captive plain washer. The pre-assembled stack supports repetitive machinery and electrical-equipment fastening without handling loose washers.
Product Overview
This specific three-piece SEMS product consists of one cross-recessed external-hex machine bolt, one captive spring lock washer directly below the head and one captive flat washer below the spring washer. GB/T 9074.13-1988 is the applicable current assembly reference for M3–M8 products where dimensions conform.
The external hex accepts socket, wrench or nut-driver tooling, while the centered cross recess supports compatible screwdriver or powered-driver access. These interfaces offer tooling flexibility but are not claimed to have identical torque capacity. Both washers remain mechanically retained on the finished bolt.
Specify M size, pitch, length, cross recess, bolt material, spring-washer material, flat-washer material, washer dimensions, finish, GB/T standard or customer drawing, mating thread, quantity and application.
Technical Specifications
Dual-Drive Hex Head, Captive Washer Stack & Thread Engagement
Material, Size & Finish Options
Washer Dimensions & OEM Manufacturing
Diameter, pitch, length, across flats, head height, cross recess and thread length.
Spring-washer OD, thickness, free height, material and geometry; plain-washer OD, ID, thickness and material.
Specify bolt and both washer materials separately, plus size, finish, standard/drawing, quantity, application and sample.
Inner bags, boxes, bulk packaging, export cartons, pallets, labels, customer part numbers and authorized private label.
Head, Washer & Captive Assembly Quality
Inspection verifies component count, head form, across flats, recess centering/depth, washer split and flatness, rolled thread and captive retention. Materials are verified separately for bolt, spring washer and flat washer. Documents may include MTC, dimensional, thread, washer, captive-assembly or coating reports where applicable.
Applications
Dual-drive captive-washer fasteners for repeatable OEM machine-thread assembly.
Captive washers simplify cabinet structures, brackets and equipment components.
External-hex installation with a predefined spring-and-flat-washer stack.
Consistent flat-washer bearing interface without loose-part handling.
Dual drive supports compatible production-line tooling choices.
GB/T 9074.13 or drawing-based supply in specified material, finish and packaging.
Frequently Asked Questions
What is a Cross Recessed Hex Head Three-Piece SEMS Bolt?
It combines one dual-drive machine bolt, one captive single-coil spring washer and one captive plain washer into a pre-assembled fastener.
What standard applies to this product?
GB/T 9074.13-1988 is the current Chinese national assembly standard and covers M3–M8 thread sizes where dimensions conform.
How does GB/T 9074.13 differ from a plain Hex Head combination bolt?
9074.13 includes a centered cross recess in its indented external-hex head; the GB/T 9074.17 family uses a plain hex head without the same cross-recessed configuration.
Are the Spring Washer and Flat Washer loose?
No. Both are captive; a common process installs them before final thread rolling so the completed thread prevents normal detachment.
Can these SEMS Bolts be supplied in stainless steel?
Yes. VALTOR can supply 304/A2, 316/A4 and carbon-steel configurations. Bolt, spring-washer and flat-washer materials should each be confirmed.
Related Products
Share size, length, recess, bolt and washer materials, washer dimensions, finish, standard/drawing and quantity with VALTOR.