Captive Screws from Wixroyd
What is...
A Captive Screw is a fastener specially designed to remain in place within an assembly when the assembly is removed. They achieve this by having the threaded section a larger diameter than the main length of the screw. Their primary use is for guard panels and safety guards to comply with EU Machine Safety Directive 2006/42/EC, which requires fasteners remain attached to fixed guards or equipment when guards are removed.
Wixroyd Captive Screws are manufactured mainly from stainless steel (A2) but are also available in aluminium, brass or zinc plated steel. Our technical support team can help provide you with assistance on making sure your application complies with the EU safety directive or general technical help on their use.
For more information on how to prepare your application and how to install your captive screw, or any other questions you might have, please visit our Technical section or feel free to contact one of our friendly and knowledgable team members.
OPTIONS
Captive Screws with selection of heads
These screws have a reduced diameter shank and should not be tightened to the recommended torque for an equivalent machine screw of size d1.
Available in stainless steel A2 and marine grade A4, black oxide coated B2 and B4 stainless steel, titanium grade T2 and T4, and on request even in steel (anodised, black oxide or zinc plated), brass, aluminium etc.
Stainless steel AISI 316.
Hex drive.
Suitable for outdoors, medical and marine applications.
Stainless steel AISI 316.
Hex drive.
Suitable for outdoors, medical and marine applications.
Not available in titanium.
Imperial.
Stainless steel AISI 303.
Slot and hex drive.
Stainless steel AISI 303.
With Anu-Lok 180 locking patch.
Hex drive; torx also available.
Black oxide coated, stainless steel AISI 316.
Torx drive.
M 8 sizes have a reduced TX size.
Stainless steel AISI 303.
Hex drive.
To accommodate the slight undercut at the top of the shank, the hex socket is smaller than on a similar threaded machine screw.
Black oxide coated, stainless steel AISI 303.
Torx drive.
M 8 sizes have a reduced TX size.
Captive Thumb Screws
These screws have a reduced diameter shank and should not be tightened to the recommended torque for an equivalent machine screw of size d1.
Available in stainless steel A2, marine grade A4, blackened stainless steel B2 and B4, and titanium T2 and T4. Upon request, also available in steel (anodied, black oxide or zinc plated), brass, aluminium etc. Thin or large heads.
Stainless steel AISI 303.
Tensile strength 550 N/mm2.
Proof stress min. 190 N/mm2
Stainless steel AISI 316, marin grade.
Tensile strength 480 N/mm2.
Proof stress min. 200 N/mm2.
Titanium T2, tensile strength 345 N/mm2.
Titanium T5, tensile strength 900 N/mm2.
Slot drive.
Black oxide coated, stainless steel AISI 303.
Slot drive.
Tensile strength 550 N/mm2.
Proof stress min. 190 N/mm2.
Captive Bolts, Washers and Retainer Flanges
Stainless steel, AISI 303.
Reduced diameter shank.
Also available in marine grade A4, blackened stainless steel B2 and B4, and titanium T2 and T4. Upon request, also available in steel (anodied, black oxide or zinc plated), brass, aluminium etc.
For captive screws.
With very shallow thread in the i/d, to prevent separation from the screw or bolt.
Available in stainless steel A2, marine grade A4, blackened stainless steel B2 and B4, and titanium T2 and T4 and in steel (black oxide or zinc plated),.
Stainless steel AISI 303.
For retaining captive screws in a panel.
Also available in marine grade stainless steel AISI316, steel (anodised, black oxide or zinc plated) and brass.
General Guidance
One option to retain screws to panels are our Retaining Washers. Used in place of Retainer Flanges, Retaining Washers are simple but effective when used with our Captive Screws. The Captive Screws have a normal thread and a reduced diameter for the rest of the screw length.
The Retaining Washer has a small length of thread on the internal diameter and once screwed on to the Captive Screw is effectively captive.
Preparation
- Selection retainer based upon panel thickness
- Countersink panel
Applications
Screw the thin Retaining Washer onto the Captive Screw and the screw is therefore retained to the panel.
Material Coatings
Many finishes can be applied - black oxide finish, anodizing etc.
The main options are as follows:
Finish | Notes |
| Black Chrome (MIL-C-1458B) | Black chrome is hard, non-reflective coating which is resistant to abrasion, heat and erosion. The black chrome surface is a dull, dark grey and may be waxed or oiled to darken surface. |
| Black Oxide Coating (MIL-C-13924B) | Black oxide is a uniform black coating for ferrous metals. Generally it is considered a decorative coating and provides only very limited corrosion protections under mild corrosion conditions. |
| Cadmium | Cadmium is a bright, silvery white plating. Supplementary treatments for type II can be golden, iridescent, amber, black or olive drab. |
| Passivate (QQ-P-35/MIL S-5OOSC) | Passivation is a process designed to remove foreign metals from the surface of stainless and corrosion resistant steels. |
| Phosphate Coating Ligth (TT-C-0D490B) | Phosphate coating is a light coating for use as a base paint. |
| Gold (MIL-G-45204B) | Yellow to orange colour depending on a proprietary process used. Will range from matt to bright finish depending on base metal. Good corrosion resistance and high tarnish resistance. |
| Nickel | Nickel is a corrosion protective plating for steel, zinc and zinc alloys as well as copper and copper alloys. |
| Zinc (QQ-Z-325C) | The primary use of chromate finishes on zinc is to retard or prevent formation of white corrosion products on zinc surfaces. |
Head Types
Different head types for factors like ease of access, security needs, aesthetics, and the specific application.
Schematic | Drive Types | Uses |
 | Hexagonal recess | Ideal for precision assembly. Most recommended where less surface area is available. |
 | Crosshead (Phillips®) | Provides good control in driving. Always use a driver bit of the proper size which is in good condition. |
 | Star Head (Torx®) | Positive-engaging, fast-locating method which transmits drive torque with less required downward pressure. Good fastening appearance. |
 | Slotted | Accepts standard blade screwdriver. Requires less downward pressure to drive parts than those with recessed openings. Use a proper fitting blade to minimise slippage. |
 | Security | These screws are impossible to remove without the special matching screw driver. |
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Alexia House, Glenmore Business Park
PO19 7BJ Chichester
United Kingdom
0333 207 4497
sales@wixroyd.com
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Company registration no: 00496138
Company VAT number GB 408154022
