Stainless Steel Hex Head Machine Screw
Specification
Stainless Steel Hex Head Screws and Bolts
PO JUN supplies stainless steel hex head screws and bolts in inch diameters from 3/16" to 1-1/4", with available lengths from 1/2" to 15".
These fasteners feature an external six-sided hex head for wrench or socket installation. Depending on the size, thread configuration, and applicable standard, they may also be referred to as stainless steel hex bolts, hex cap screws, or hex head machine screws.
Full-thread and long-length options are available according to the required specification. Thread type, material grade, and dimensions should be confirmed before ordering.
Product Configuration
Plain Hex Head
The standard configuration features a plain external hex head without an integral flange. Head dimensions can be matched to the applicable standard or customer drawing.
Washers are not included unless specifically required and quoted separately.
Forged Large-Diameter Products
The 1-1/8" and 1-1/4" diameters in the current size chart are identified as forged products. Material, mechanical properties, head dimensions, and inspection requirements should be confirmed according to the application.
Available Inch Sizes
| Diameter | Available Lengths |
|---|---|
| 3/16" | 1/2", 5/8", 3/4", 1", 1-1/4", 1-1/2", 1-3/4", 2", 2-1/2", 3" |
| 1/4" | 1/2", 5/8", 3/4", 1", 1-1/4", 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6" |
| 5/16" | 1/2", 5/8", 3/4", 1", 1-1/4", 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6" |
| 3/8" | 1/2", 5/8", 3/4", 1", 1-1/4", 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8", 8-1/2", 9", 9-1/2", 10", 11", 12", 13", 14", 15" |
| 7/16" | 3/4", 1", 1-1/4", 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4" |
| 1/2" | 3/4", 1", 1-1/4", 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8", 8-1/2", 9", 9-1/2", 10", 11", 12", 13", 14", 15" |
| 5/8" | 1", 1-1/4", 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8", 8-1/2", 9", 9-1/2", 10", 11", 12", 13", 14", 15" |
| 3/4" | 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8", 8-1/2", 9", 9-1/2", 10", 11", 12", 13", 14", 15" |
| 7/8" | 1-1/2", 1-3/4", 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8", 8-1/2", 9", 9-1/2", 10" |
| 1" | 2", 2-1/2", 3", 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8", 8-1/2", 9", 9-1/2", 10" |
| 1-1/8" | 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8" — forged product |
| 1-1/4" | 3-1/2", 4", 4-1/2", 5", 5-1/2", 6", 6-1/2", 7", 7-1/2", 8" — forged product |
Diameter and length alone do not define a complete fastener. Thread series, material grade, thread coverage, head dimensions, and applicable standards should be confirmed before ordering.
Thread Options
Inch stainless steel hex bolts may be supplied with different thread series and configurations. Specify the required thread according to the mating nut, tapped hole, drawing, or applicable standard.
- UNC, UNF, or other thread series
- Threads per inch
- Thread class
- Full or partial thread
- Required thread length
- Right-hand or left-hand thread
For example, “1/2-inch stainless steel hex bolt” does not identify whether the required thread is UNC or UNF.
Stainless Steel Grades
Stainless steel hex head screws and bolts can be manufactured in different grades according to application requirements. Common options include 304 and 316 stainless steel.
Grade selection depends on corrosion resistance, mechanical requirements, service environment, and the applicable material specification. Material certificates, passivation, cleaning, and testing can be specified when required.
Full Thread or Partial Thread
The product images show fully threaded examples. Longer stainless steel bolts may also be supplied with an unthreaded shank when required by the application.
For assemblies that use the smooth shank for alignment, positioning, or shear transfer, the required thread length and shank length should be specified.
Head Dimensions
The standard product has a plain external hex head without an integral flange. When installation space or tooling clearance is limited, the required head dimensions should be confirmed with the applicable standard or drawing.
Typical dimensions include width across flats, head height, bearing face, chamfer, and under-head fillet.
Common Applications
Subject to material, mechanical, and dimensional requirements, stainless steel hex head screws and bolts may be used for:
- Industrial machinery
- Equipment frames and brackets
- Conveyor and automation assemblies
- Metal structures and fabricated parts
- Commercial hardware
- Outdoor equipment
- Marine hardware components
- Food-equipment assemblies
- Maintenance and replacement parts
- Custom OEM products
Structural, pressure-containing, transportation, and safety-related applications require the appropriate material, mechanical properties, inspection requirements, and applicable code to be confirmed before use.
Stainless Steel Thread Galling
Stainless steel bolts and nuts can be susceptible to thread galling during assembly, especially with high installation speed, damaged threads, dry surfaces, or excessive torque.
To reduce the risk of galling, consider the bolt and nut material combination, thread condition, installation speed, tightening method, and any required lubricant or anti-seize compound. When lubricant is used, the specified torque may need to be adjusted.
RFQ Checklist
PO JUN has manufactured screws and nuts since 2003. For an accurate quotation, provide the following key information:
- Part name or buyer part number
- Diameter and length
- Thread series and threads per inch
- Thread class and thread length
- Full or partial thread
- Stainless steel grade
- Material or dimensional standard
- Required mechanical properties
- Head dimensions when non-standard
- Surface treatment, passivation, cleaning, or lubrication requirements
- Order quantity
- Packaging and labeling requirements
- Inspection or certificate requirements
- Destination country and requested delivery date
- Drawing or sample when available
Providing the basic thread, material, dimensional, and quantity information helps PO JUN review the specification and prepare an accurate quotation.
Frequently Asked Questions
Is this product a machine screw, hex cap screw, or hex bolt?
The terminology can vary according to size, length, thread coverage, and applicable standards. For international purchasing, a drawing or standard number should be used to define the required product.
Are all sizes fully threaded?
The product images show fully threaded examples, but thread coverage is not specified for every listed length. Specify full thread or the required thread length when requesting a quotation.
Are 304 and 316 stainless steel available?
304 and 316 are common stainless steel options. Availability depends on the required size, specification, quantity, and production requirements.
Are the threads UNC or UNF?
The size chart does not specify the thread series. UNC, UNF, or another thread series should be stated in the purchase specification.
How is hex bolt length measured?
Hex head fastener length is commonly measured from the bearing surface under the head to the end of the fastener. The applicable standard or purchase drawing should control the measurement method.
What does “forged product” mean for 1-1/8" and 1-1/4"?
The current size chart identifies these two diameters as forged products, with listed lengths from 3-1/2" through 8". Specific forging, dimensional, material, and inspection requirements should be confirmed for the application.
Is a washer included?
The product is a plain hex head fastener. A flat washer, spring washer, sealing washer, or other washer should be specified separately if required.
Can these fasteners be used outdoors?
Outdoor suitability depends on the stainless steel grade, exposure to salt or chemicals, contact with other metals, surface condition, and maintenance requirements. The service environment should be considered when selecting the material grade.