How to Build a Fastener Part Number
A structured part number encodes the key attributes so people and systems can read it. Consistency matters more than any particular scheme.
Example structure
| Segment | Example | Meaning |
|---|---|---|
| Product | HCS | Hex cap screw |
| Diameter-thread | 050-13 | 1/2-13 |
| Length | 0200 | 2 in |
| Grade | G5 | SAE Grade 5 |
| Finish | ZY | Zinc yellow |
Example: HCS050-13-0200-G5-ZY. Many distributors use compact codes such as 50C200HCS5Z; the key is one rule applied everywhere.
These tables carry the same figures as the printed sheet below.
The printed sheet
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Text version of this sheet
How to build a fastener part number
What it is
AT A GLANCE
PART NO.
A structured part number encodes the key attributes so people and systems can read it. Consistency
matters more than any particular scheme.
A good part number decodes itself
Example structure
Segment
Example
Meaning
Product
HCS
Hex cap screw
Diameter-thread
050-13
1/2-13
Length
0200
2 in
Grade
G5
SAE Grade 5
Finish
ZY
Zinc yellow
Example: HCS050-13-0200-G5-ZY. Many distributors use compact codes such as 50C200HCS5Z; the key is one rule applied everywhere.
Key points
Never reuse a retired part number for a different part.
Governing standards: Internal / distributor practice. Editions shown are the latest confirmed as of September 2026. The drawing and the governing standard always take precedence
over this sheet.
torquing any fastener. Verify the current governing standard, project documents, OEM requirements, size, thread, coating and lot certification. To the fullest extent permitted by law, The Fastener App disclaims liability
arising from reliance on this reference.
Fastener Guide reference FG-B521F3 · thefastenerapp.com/fastener-guide/specification-control/how-to-build-a-fastener-part-number · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
