"Tempo" instead of "paper tissue", "Sellotape" instead of "adhesive tape", "google" instead of "use an internet search engine" - every child knows these terms, which are known as deonyms in linguistics. Similarly, in precision engineering circles, the term "helicoil" has been used for decades to stand for "repair thread insert for (soft) metallic materials". In fact, however, this is the registered brand name of the thread inserts manufactured by Bölhoff.
These inserts are now also available for defective bicycle pedal threads with the dimensions UN 9/16"-20. If you destroy the thread in the crank arm when trying to unscrew an old, completely corroded pedal, you don't have to buy a new crank straight away. Without dismantling the crank, the new thread is created in a single operation using a combined drilling and cutting tool - without pre-drilling. A high-strength wire is then screwed in as a thread insert. Additional locking elements or adhesive are not required, and the repaired thread is even more robust than before.
Further information: www.boellhoff.com
Sebastian Brust
Editor
