Captive Screws From Automotion
A captive screw is a fastener specially designed to remain in place within an assembly when the assembly is removed.In general the captive screw has a thinner diameter shoulder over the length of the screw, then a threaded portion at the end. This means that when you remove a panel by unscrewing the captive screw, it does not come away from the cover itself. This makes them important fasteners for safety equipment where you need to avoid loose components.
For example removing a cover panel such as a guard panel from an assembly whilst performing maintenance, the screw is required remain with the guard so that the guard or cover can be easily replaced.
In general the captive screw has a thinner diameter shoulder over the length of the screw, then a threaded portion at the end. When fixing in place the screw is screwed through the panel (or cover) and then into the final part of the structure.
Our standard range of captive screws with threads sizes from M3 to M12 - and a large number of lengths up to 80mm to suit customer applications.
Captive Phillips drive pan head screws available in M2.5 to M6. Stainless steel version
These are special thin diameter head type captive thumb screws and are available in M3, M4, M4, M5 and M6. Lengths from 8mm to 60mm.
Captive button head screws with either hex or Torx drive. In stainless steel A2 AISI 303 (other materials on request). Thread sizes M2.5 to M6, lengths 8mm to 60mm.
These are special threaded captive washers that are often used in conjuction with our captive screws. Stainless steel (grade A2 and A4, AISI 303 AISI 316) and zinc-plated steel.
Available in thread sizes M2.5, M3, M3.5, M4, M5, M6, M8, M10 and M12.
Our standard range of captive hex bolts/screws with threads sizes M3 to M12 - and a large number of lengths up to 80mm to suit customer applications
Standard captive thumb screws in M3, M4, M5 and M6. Lengths from 8mm to 30mm.
Countersunk (hex drive) captive screws in thread sizes M2 to M6. Lengths from 10mm to 60mm. Stainless steel (A2) - zinc-plated steel and other versions on request.
These are special thin diameter shank screws with pointed end for easy location of the screw and are available in M3, M4, M5 and M6. Lengths from 8mm to 50mm.
Associated Products
Materials
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. |
| Schematic | Drive Types | Uses |
 | Hexagonal recess | Ideal for precision assembly. Most recommended where less surface area is available. |
 | Crosshead (Phillips®) | Provides good control in driveing. 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. |
Applications
Retaining washers
These are simple but effective when used with our captive screws. The captive screws have a normal thread then a reduced diameter for the rest of the screw length.
The washer has a small length of thread on the internal diameter and once screwed on to the captive screw is effectively captive.
Screw the thin retaining washer onto the captive screw and the screw is therefore retained to the panel.
