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Confirmat screw

From Wikipedia, the free encyclopedia
Confirmat screws on a sheet of the particleboard material in which they were designed to hold.
Diagram of a hex-headed confirmat screw, made to be turned with an allen key
A confirmat screw holding a butt joint in melamine-coated particleboard.
A specialized stepped drill bit and a screw to match it. The screw is covered with a cosmetic plastic cap. The Z-shaped object is an allen key.

Confirmat screws or cabinet-connecting screws[1] are screws designed to hold in particleboard, medium-density fiberboard, and similar materials.[2] They are very common in furniture assembly, but are rare in retail.[2] They may have flat or barrel heads.[3] They have a blunt tip, a large shank, and they often have shoulder, a broad length of unthreaded shank just below the head, which helps hold the screw in position.[2] They have a coarse thread, rather like masonry screws (which may match them exactly in thread).

Confirmat screws are usually screwed into stepped predrilled holes,[3] often drilled with a stepped bit.[2] Short, shoulderless confirmat screws, whose heads pass through hardware like hinges or drawer slides, may go into unstepped holes.[2]

As they are screwed in, confirmat screws compress a thread (the spiral groove) into the particle board. They do not cut a new thread if removed and re-inserted. A confirmat screw can therefore be removed and replaced dozens of times.[4] However, a confirmat screw can not be replaced by a confirmat screw with a different thread, or it will destroy the threading of the hole (filling the hole with a wooden dowel and using a woodscrew can fix a stripped hole[2]).

Confirmats may be made of steel, galvanised steel, and nickel and aluminium-zinc alloys.[5] They commonly come in lengths of 40, 50 and 70 millimetres (1.6, 2.0 and 2.8 in), and in shank sizes of 5, 6.3 and 7 millimetres (0.20, 0.25 and 0.28 in), with Phillips drive or hex heads.[4]

Ordinary wood screws do not hold well in particleboard, which is much weaker than wood. They tend to tear out.[6] Confirmat screws have about twice the shank diameter of a woodscrew. Drywall screws, while half the price of confirmat screws, do not hold as well in particleboard-like materials, and cannot be removed and re-inserted. Cam-and-bolt connectors can be swapped out, but are more complex and expensive;[4] confirmat manufacturers say they cams are also weaker than confirmats, if better than drywall screws.[4][third-party source needed]

Confirmat screws were formerly under patent, but the patent has expired, and they are now made by many companies.[4]

Etymology

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The name comes from the Latin word confirmat, meaning "it makes [something] firm or strong".[2]

See also

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References

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  1. ^ "Make MDF Joints That Last". WOOD Magazine. Retrieved 22 September 2024.
  2. ^ a b c d e f g Baker, Ron (20 April 2024). "What Confirmat Screws Are, And Why Your Cabinets Need Them". House Digest. Retrieved 22 September 2024.
  3. ^ a b "Confirmat Screws and Drill Guides". www.woodweb.com. Retrieved 22 September 2024.
  4. ^ a b c d e Gibson, Scott (27 June 2008). "What's the Difference: Cabinet assembly screws". Fine Homebuilding. Retrieved 22 September 2024.
  5. ^ "What are confirmats?". Furnica., a furniture fittings supplier.
  6. ^ "Does Particle Board Furniture Need Special Screws (Vs Regular Wood Screws)?". www.thewoodworkplace.com. Retrieved 22 September 2024.
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