Set Screws: Complete Guide
Types, Point Styles, Torque Specs & Applications for Securing Collars, Pulleys, Gears & Shafts
Set Screw Types
Socket, square, and slotted configurations
Point Styles
Cup, cone, flat, dog, and oval points
Sizes & Torque
Complete sizing chart with torque specifications
Applications
Collars, pulleys, gears, and shaft mounting
Downloadable Reference Guides
Quick access to all set screw specification charts and guides
What Are Set Screws?
Set screws (also called grub screws or blind screws) are headless threaded fasteners designed to secure one component to another, typically to hold collars, pulleys, gears, or other rotating components onto shafts. Unlike traditional screws, set screws are fully threaded with no protruding head, allowing them to sit flush or below the surface of the mounted component.
The lack of a head means set screws are driven using special tools (hex keys, square drivers, or screwdrivers depending on type) and rely entirely on their point pressing against the mating surface to create holding force. Different point styles optimize set screws for specific applications and materials.
Key Advantages of Set Screws
No protrusion: Headless design sits flush or recessed, eliminating snag hazards and allowing close clearances.
Simple installation: Quick to install and remove with appropriate driver, no head to strip.
Adjustable clamping: Can be tightened or loosened to adjust component position on shaft.
Compact design: Small footprint allows use in tight spaces where headed fasteners won't fit.
Multiple point options: Different point styles optimize performance for various materials and applications.
Set Screw Types by Drive Style
Socket Head Set Screws (Hex Socket)
Most common type featuring hexagonal socket in the end for drive with hex keys (Allen wrenches). Preferred for modern applications.
- Hex socket drive (most common)
- High torque capacity
- Less likely to strip than slotted
- Available in all point styles
- Metric and inch sizes
Square Head Set Screws
Features square socket drive requiring square drive bits. Provides excellent torque transfer and visibility.
- Square socket drive
- Very high torque capacity
- Easy visual inspection
- Less common than hex socket
- Preferred in some industrial applications
Slotted Set Screws
Traditional style with flat screwdriver slot. Lower torque capacity but universally compatible with standard screwdrivers.
- Flat screwdriver slot
- Lower torque capacity
- More prone to cam-out and stripping
- Widely available, inexpensive
- Legacy equipment compatibility
Headless Set Screws (Full Thread)
Completely threaded from end to end with point on one side and drive on the other. Maximum thread engagement.
- Full-length threads
- Maximum holding power
- Various drive styles available
- No unthreaded shank section
- Best for deep tapped holes
Knurled Set Screws
Features knurled grip area for hand tightening without tools. Used where frequent adjustment is needed.
- Knurled exterior for hand grip
- Tool-free adjustment
- Lower torque applications
- Frequent adjustment scenarios
- May protrude slightly
Nylon Tip Set Screws
Features nylon pellet at point to prevent marring soft shafts while providing vibration resistance.
- Nylon pellet at tip
- Protects soft materials
- Vibration dampening
- Non-marring contact
- Lower holding force than steel point
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Call (866) 573-0445 Browse All Set ScrewsSet Screw Point Styles
The point style is critical to set screw performance and should be selected based on the material being secured and whether permanent marking is acceptable.
Cup Point
Most common point style featuring a cup-shaped indentation that bites into the shaft for secure grip.
- Circular cup indentation in point
- Creates dimple in shaft surface
- Excellent grip and torque resistance
- Best for: steel shafts, permanent installations
- Standard choice for most applications
Cone Point (Full Dog)
Sharp conical point designed to seat in a pre-drilled dimple or detent in the shaft for positive location.
- Sharp 118° cone angle
- Requires pre-drilled dimple in shaft
- Most secure holding power
- Best for: precision positioning, high torque
- Prevents axial and rotational movement
Flat Point
Flat-ended point for applications where shaft damage must be minimized or frequent adjustment is required.
- Flat, smooth end surface
- Minimal shaft marking
- Lower holding power than cup/cone
- Best for: frequent adjustments, soft materials
- Requires smooth shaft surface
Dog Point (Half Dog)
Cylindrical extension that fits into a drilled hole in the shaft for precise alignment and high shear resistance.
- Cylindrical pilot extends from point
- Fits into drilled hole in shaft
- Highest shear strength
- Best for: precise positioning, heavy loads
- Prevents rotation under high torque
Oval Point
Rounded point provides moderate grip with minimal shaft damage, suitable for soft materials.
- Smooth rounded end
- Low shaft marking
- Moderate holding power
- Best for: soft shafts, temporary setups
- Good for aluminum and brass
Nylon Pellet Point
Nylon tip prevents marring of precision shafts while providing vibration dampening and non-metallic contact.
- Soft nylon contact surface
- Zero shaft marking
- Vibration resistant
- Best for: precision shafts, sensitive finishes
- Lower holding force requires care
Point Style Selection Guide
Cup Point: General purpose, standard for steel shafts - use when permanent marking acceptable
Cone Point: High torque, precision location - requires pre-drilled dimple
Flat Point: Frequent adjustment, minimal marking - lower holding power
Dog Point: Maximum shear strength - requires drilled hole in shaft
Oval Point: Soft materials (aluminum, brass) - moderate grip
Nylon Point: Precision shafts, no marking - lowest holding force
Download Point Style Selection Guide
Comprehensive comparison of all set screw point types with selection criteria
Download Point Style Guide (PDF)Looking for Specific Point Styles?
We stock set screws in all point configurations with quick delivery on standard sizes.
Shop All Set Screws Get Expert AdviceSet Screw Sizes and Torque Specifications
Set screws are available in metric and inch sizes. Socket head set screws use standard hex key sizes for their drive.
Inch Sizes - Socket Head Set Screws
| Thread Size | TPI (UNC) | Hex Socket Size | Cup Point Torque (in-lbs) | Cone Point Torque (in-lbs) | Common Lengths |
|---|---|---|---|---|---|
| #4-40 | 40 | 0.050" (1/20") | 3-4 | 2-3 | 1/8" - 1/2" |
| #6-32 | 32 | 1/16" | 7-9 | 5-7 | 1/8" - 5/8" |
| #8-32 | 32 | 5/64" | 13-17 | 10-13 | 1/8" - 3/4" |
| #10-24 | 24 | 3/32" | 22-27 | 17-22 | 1/8" - 1" |
| 1/4"-20 | 20 | 1/8" | 65-85 | 50-65 | 1/4" - 2" |
| 5/16"-18 | 18 | 5/32" | 130-165 | 100-130 | 1/4" - 2" |
| 3/8"-16 | 16 | 3/16" | 230-290 | 175-230 | 3/8" - 3" |
| 1/2"-13 | 13 | 1/4" | 515-650 | 390-515 | 1/2" - 4" |
| 5/8"-11 | 11 | 5/16" | 1020-1280 | 770-1020 | 5/8" - 4" |
| 3/4"-10 | 10 | 3/8" | 1760-2200 | 1330-1760 | 3/4" - 6" |
Note: Torque values are for dry, steel set screws into steel tapped holes. Reduce torque by 25-30% for lubricated threads or softer materials. Cone point values are lower due to point concentration risk.
Metric Sizes - Socket Head Set Screws
| Thread Size | Pitch (mm) | Hex Socket Size | Cup Point Torque (Nm) | Common Lengths |
|---|---|---|---|---|
| M3 | 0.5 | 1.5 mm | 0.4-0.6 | 3-16 mm |
| M4 | 0.7 | 2 mm | 1.0-1.4 | 4-20 mm |
| M5 | 0.8 | 2.5 mm | 2.0-2.7 | 5-25 mm |
| M6 | 1.0 | 3 mm | 3.5-4.7 | 6-30 mm |
| M8 | 1.25 | 4 mm | 8.5-11.5 | 8-40 mm |
| M10 | 1.5 | 5 mm | 17-22 | 10-50 mm |
| M12 | 1.75 | 6 mm | 29-39 | 12-60 mm |
| M16 | 2.0 | 8 mm | 70-95 | 16-80 mm |
⚠️ Critical Torque Considerations
Do not over-torque: Excessive torque can strip threads in the collar/hub or shear the set screw point.
Use correct hex key: Worn or wrong-size hex keys round out socket and prevent proper tightening.
Multiple set screws: When using multiple set screws, tighten in a star pattern to distribute clamping force evenly.
Threadlocker: Apply threadlocker (Loctite 243) to prevent loosening from vibration - especially critical for rotating assemblies.
Material matters: Soft materials (aluminum, brass) require reduced torque to prevent thread damage.
Download Size and Torque Chart
Complete sizing with recommended torque specifications for all common sizes
Download Size & Torque Chart (PDF)Need Specific Sizes or Bulk Quantities?
We stock set screws in all standard sizes with volume pricing available for industrial customers.
Shop Set Screws Request Bulk QuoteCommon Applications
Shaft Collars
Securing shaft collars to position and lock components on linear or rotary shafts.
- Single-piece clamp collars
- Two-piece split collars
- Thrust collars for axial positioning
- Cup or flat point recommended
- Multiple screws for heavy loads
Pulley and Sprocket Mounting
Securing pulleys, sprockets, and timing gears to shafts in power transmission systems.
- V-belt pulleys
- Chain sprockets
- Timing belt pulleys
- Cone point for pre-drilled dimples
- Use threadlocker for vibration
Gear Hubs
Mounting gears to shafts in gearboxes, transmissions, and mechanical drives.
- Spur gears
- Bevel gears
- Worm gears
- Dog point for high torque
- Precision positioning critical
Knobs and Handles
Securing knobs, handles, and hand wheels to control shafts and valve stems.
- Machine knobs
- Hand wheels
- Control handles
- Flat or oval point to minimize marking
- Easy position adjustment
Linear Motion Components
Positioning bearings, bushings, and motion components on guide shafts and rails.
- Linear bearings
- Pillow block bearings
- Bushing mounts
- Cup point for general use
- Frequent readjustment capability
Adjustable Stops and Limits
Creating adjustable mechanical stops, travel limits, and positioning references.
- Travel limit stops
- Adjustable jigs and fixtures
- Position references
- Flat point for adjustment
- Locknut for position holding
Download Set Screw Application Guide
Common uses and project examples with specifications and recommendations
Download Application Guide (PDF)Installation Best Practices
Preparation
- Clean surfaces: Remove oil, dirt, and debris from shaft and tapped hole threads
- Inspect threads: Verify tapped hole threads are not damaged or cross-threaded
- Check alignment: Ensure collar/hub bore is perpendicular to set screw axis
- Pre-drill dimples: For cone or dog point, pre-drill proper sized dimple in shaft
- Select correct point: Match point style to shaft material and application requirements
Installation Procedure
- Thread set screw by hand: Start threading set screw manually to avoid cross-threading
- Use correct hex key: Select proper size hex key that fits snugly in socket
- Position component: Adjust collar/hub to desired position on shaft before final tightening
- Apply threadlocker (if needed): For vibration-prone applications, apply medium-strength threadlocker
- Tighten to specification: Use torque wrench for critical applications to reach recommended torque
- Multiple screws pattern: If using multiple set screws, tighten in star/cross pattern for even load
- Verify position: Check component position after tightening - may shift slightly under clamping force
Safety Wire (Critical Applications)
For applications where loosening could cause failure or injury, use safety wire through set screw socket and tie-off:
- Aerospace and high-reliability applications
- Rotating assemblies at high RPM
- Safety-critical mechanisms
- Applications where inspection is difficult
⚠️ Common Installation Mistakes
- Using worn hex keys: Rounds out socket making removal impossible - use new, correctly sized keys
- Over-tightening: Strips threads or shears point - use torque specifications
- Wrong point style: Cup point on soft shaft creates excessive damage; flat point on steel has poor grip
- No threadlocker on vibration: Set screws loosen from vibration - always use threadlocker for rotating parts
- Insufficient thread engagement: Need minimum 1× diameter thread depth for full holding power
- Dirty threads: Contamination causes false torque reading - clean before installation
Download Set Screw Installation Guide
Step-by-step procedures for proper set screw installation and best practices
Download Installation Guide (PDF)Material and Finish Options
Alloy Steel (Grade 45H or Stronger)
Most common material for set screws requiring high holding power:
- Black oxide finish: Basic corrosion resistance, most economical
- Zinc plated: Better corrosion protection for indoor use
- Heat treated: Hardened to 45-53 HRC for maximum strength
- Use for: General industrial applications, steel shafts
Stainless Steel (18-8 or 316)
Corrosion-resistant option for harsh environments:
- 18-8 stainless (304): Good corrosion resistance, lower strength than alloy steel
- 316 stainless: Superior corrosion resistance, marine applications
- Slightly magnetic: Due to cold working during manufacture
- Use for: Outdoor, marine, food processing, chemical exposure
Brass
Non-magnetic, electrically conductive option:
- Excellent machinability
- Non-magnetic properties
- Electrical conductivity
- Lower strength than steel
- Use for: Electrical equipment, non-magnetic assemblies
Nylon/Plastic
Non-marring, insulating option for specialized uses:
- Will not damage precision shafts
- Electrical insulation
- Very low holding force
- Not for high-torque applications
- Use for: Delicate finishes, temporary positioning
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