// TECHNICAL RESOURCES
Mil-Spec materials and finishes.
Understand the material, treatment and lubrication details that belong in a complete fastener requirement.
// READING THE CALLOUT
Read the requirement in three layers
| Item | Reference |
|---|---|
| Base material | The alloy or material grade of the part. |
| Condition and performance | Heat treatment, hardness, strength and other requirements stated by the controlling specification. |
| Surface treatment and lubricant | Passivation, plating, supplemental treatment and lubrication, where required. |
These layers work together. A matching thread size and a similar-looking finish do not establish the same fastener requirement. Send Webson the complete designation and any drawing notes so the full combination can be reviewed.
// BASE MATERIAL
Common material descriptions
| Term | What it tells you | What to confirm |
|---|---|---|
| CRES / stainless steel | CRES means corrosion-resistant steel. It describes a material family, rather than a single alloy or strength level. | Retain the exact alloy, condition and product specification. A general stainless description does not establish an equivalent part. |
| 303 / 303Se | These are specific corrosion-resistant steel designations used in some hardware families. | Preserve the grade called out by the selected series and any material suffix. |
| Alloy steel | A base-material description used in specification-controlled hardware. The grade and heat treatment remain part of the requirement. | Provide the required grade, strength or hardness condition and protective treatment. |
| A286 | A distinct alloy designation used in aerospace hardware, including some threaded-insert options. | Keep the specified material condition and processing requirements; do not substitute a generic stainless description. |
| Other specified alloys | A drawing may identify aluminum, brass, nickel-copper or another material. | Quote the complete alloy and condition as specified, rather than selecting material by appearance. |
// FINISH REQUIREMENTS
Common surface treatments and lubricants
| Treatment | What it describes | What to send Webson |
|---|---|---|
| Passivation | A treatment for specified corrosion-resistant steels that addresses surface contamination such as free iron. It is distinct from depositing a metal plating. | Supply the required process specification, method/type and verification requirements when stated. |
| Cadmium plating | An electrodeposited metal coating that appears in some military hardware requirements. | Retain the exact specification, type, class and any additional processing requirements. Ask Webson to review any proposed alternative. |
| Zinc-nickel plating | A separate coating designation from cadmium or ordinary zinc plating. Some series define specific options. | Do not replace one coating with another using color or appearance. Provide the exact callout and application restrictions. |
| Dry-film lubricant | A surface-applied lubricant that may be specified in addition to a base material or coating. | Identify the lubricant specification and type. Locking and lubrication requirements may depend on the application. |
| Other coating or treatment | The finish may be controlled by a drawing note, part-number suffix or referenced process specification. | Include the complete requirement, including any supplemental treatment. A finish name alone may be incomplete. |
// SERIES-SPECIFIC EXAMPLE
One family shows why the suffix matters
MS51830 keylocking inserts distinguish material, coating and internal locking options within a single series. Revision G includes CA for A286 and QX for zinc-nickel plated alloy steel. Its L and LM locking suffixes distinguish aerospace and non-aerospace lubrication requirements.
Those codes belong to that series. They should not be copied into other MS, NAS or AN part numbers as universal material or finish rules.
// DISCUSS THE REQUIREMENT
Questions to resolve before changing a finish
- Does the drawing permit an alternative material or coating?
- Does the proposed part preserve dimensions, thread fit and specified performance?
- Are application-specific lubrication or locking requirements retained?
- Will the required certificates and processing records be available?
- Who must approve the change before purchase?
If a finish is difficult to source, ask Webson to review the exact requirement. Any proposed alternative should be identified separately for the appropriate approval.
// SOURCE WITH WEBSON
Have a part number or bill of material?
Send the complete designation, quantity, required delivery date and documentation requirements. Webson will review your requirement for quotation.