We have a query where a contractor wants to cut down the projection of resin anchors in a column baseplate. They are asking what the minimum projection of bolt above the nut should be. I had it in my head as 2 full threads but I think it is for connections. Can you please advise what the minimum number of threads above the nut should be? Thanks
Thanks for the question however it is not something that we would recommend as cutting would remove the corrosion protection as well as head marking which identifies the anchor. This could be an issue for the QA of the client as the traceability, length identification is lost, and would mean that it is reliant on proper documentation of the modifications being recorded (Who is responsible for recoding this ?) as a minimum if accepted by the client engineers.
Should the process go ahead then the tool used for cutting shall not give heat input (a disc grinder is not preferable, e.g. sawing is preferred). Generally good engineering practice considers that a minimum of two full threads are visible.