Engineering:Confirmat screw
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 blunt tips, large shanks, and often a shoulder, a broad length of unthreaded shank just below the head, which helps hold the screw in position.[2] They have coarse threads, 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 new threads 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 woodscrews. 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 that cams are also weaker than confirmats, if better than drywall screws.[4]Template: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
The name comes from the Latin word confirmat, meaning "it makes [something] firm or strong".[2]
See also
- List of screw and bolt types
- Cam fastener
References
- ↑ "Make MDF Joints That Last" (in en). https://www.woodmagazine.com/woodworking-how-to/shop-tips/fasteners-hardware/mdf-joints-that-last.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Baker, Ron (20 April 2024). "What Confirmat Screws Are, And Why Your Cabinets Need Them". https://www.housedigest.com/1563640/what-are-confirmat-screws-cabinet-benefits/.
- ↑ 3.0 3.1 "Confirmat Screws and Drill Guides". https://www.woodweb.com/knowledge_base/Confirmat_Screws_and_Drill_Guides.html.
- ↑ 4.0 4.1 4.2 4.3 4.4 Gibson, Scott (27 June 2008). "What's the Difference: Cabinet assembly screws". https://www.finehomebuilding.com/2008/06/27/whats-the-difference-cabinet-assembly-screws.
- ↑ "What are confirmats?" (in en). https://furnica.com/blogs/news/what-are-confirmats., a furniture fittings supplier.
- ↑ "Does Particle Board Furniture Need Special Screws (Vs Regular Wood Screws)?". https://www.thewoodworkplace.com/particle-board-screws-vs-wood-screws/.
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