GB 5783-1986 Hexagon Head Bolts, Full Thread, Product Grades A and B
GB 5783-1986 fully threaded hexagon head bolts, product grades A and B, M3 to M64: pitch, thread runout a, head shear c, bearing diameters, across-flats and across-corners, head height, fillet radius and wrench size ladders.
Last updated: 2026-11
Specifications
GB 5783 is the Chinese standard's full-thread counterpart to the ISO 4017-style hex bolt, and the collected table runs the whole ladder M3 to M64 — 25 sizes including the parenthesized non-preferred steps, printed with the parentheses. The attribute rows come in min/max pairs per feature: pitch P (0.5 at M3 to 6 at M64), thread runout a, head shear c, bearing face da and dw, across-corners e (Grade A and Grade B rows — at M16, 26.75/26.17 for A/B), head height k (max 2 at M3 to 40 at M64 with the min rows behind it), k1, fillet radius r, and width across flats s from 5.5 to 95 nominal with its tolerance ladder. The grade-A/grade-B distinction is visible in the table itself: at the small sizes the grade-B min/max cells print "-" (not tabulated — Grade A values only), and the e and s min rows split by grade from M5 up. Against the registered ISO 4017 page this is the GB-designation identity; quoting GB 5783 on a drawing means this ladder, in this case the 1986 edition.
| Standard / scope | GB 5783-1986 hexagon head bolts, full thread, product grades A and B — M3 to M64 with non-preferred sizes parenthesized, as printed |
|---|---|
| Pitch P / runout a | P 0.5 (M3) to 6 (M64); a max 1.5 (M3) to 18 (M64) — with grade-B "-" cells at the small sizes |
| Width across flats s | 5.5 (M3) to 95 (M64) nominal; min ladder 5.32 to 92.8 with Grade A/B rows as printed |
| Width across corners e | Grade A min 6.07 (M3) to 39.98 (M24) then 45.2 (M27) to 104.86 (M64); Grade B rows from M5 (8.63) — both carried per grade |
| Head height k / k1 | k max 2 (M3) to 15 (M24), then 17 to 40 (M64) with min and grade-B rows; k1 1.3 (M3) to 10.35 (M24), then 11.7 to 27.1 (M64) |
| Not tabulated | Lengths (full thread to the head by definition), mechanical property classes, finishes — per RFQ against the property-class standards |
Materials
- GB full-thread hex bolts ship in the usual property classes (8.8 the industrial default; 4.8 and 10.9 on request) and zinc or black finishes; the A/B on this page is the product grade of the geometry — tolerance class — not a strength grade, and the two must not be confused on the RFQ. Quote the property class, finish and any GB/ISO equivalence expectation explicitly; if the drawing says GB 5783 the 1986 geometry is what the table carries
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (GB 5783-1986 Hexagon Head Bolts, Full Thread, Product Grades A and B) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 1,000–10,000 pieces depending on size. Stock items run 3–7 days. High-strength and custom parts run 15–25 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Why do some cells print "-" in the grade-B columns at small sizes?
Because at the smaller sizes the standard tabulates the min/max geometry for product grade A only — grade B bolts in those diameters are defined by the nominal rows, not by separate tolerance bands. The collected table carries those cells as "-" exactly as printed. Practically: if your RFQ says grade A, the full max/min ladder applies; if grade B at the small sizes, expect the geometry to follow the nominal/grade-A rows. Confirm which product grade the drawing demands before quoting tolerance-critical fitments.
Is GB 5783 interchangeable with ISO 4017 hardware?
Largely yes at the common sizes — the across-flats, head height and bearing-face ladders sit on the same ISO 4014-family architecture, which is why both identities are registered separately but read similarly. The differences are in the edition details: this table is the 1986 edition (a newer GB/T revision exists upstream of the collected page), and thread runout a, e minima and the grade split carry edition-specific values. For general industrial assembly the parts interchange; for anything where a standard is cited contractually, buy to the designation the drawing prints — GB 5783 if it says GB 5783, ISO 4017 if it says ISO 4017 — and let the RFQ carry that citation through to the certificate.
Related knowledge
- What Bolt Property Classes 8.8, 10.9 and 12.9 Encode — and When High Strength Stops Being the Right Choice
- Bolt Grade Selection: ISO 898-1 8.8/10.9/12.9 vs ASTM A307 and A325
- 8.8 vs 10.9 vs 12.9 Bolts: Strength, Hardness and Cost — What the Evidence Settles
- Calculating Bolt Preload and Clamp Force: Torque, Friction and Tightening Method
- How to Determine Tightening Torque and Choose a Tightening Method for a Bolted Joint
- Fastener Failure Modes: Which Fatigue, Creep and SCC Controls the Evidence Supports
- Hydrogen Embrittlement in High-Strength Bolts: Which Grades Need Controls, Which Coatings and Baking Schedules Are Acceptable, and What to Require Before the RFQ
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support