The reaming process is used to slightly enlarge holes for steel connections. The process will take an existing hole and slowly increase its diameter. A reaming tool has a central shaft with several cutting edges running parallel to the shaft. The reamer is inserted into the hole so the edges run perpendicular to the surface the holes are drilled into. A reaming tool is used to remove little material from the inside of the hole so the most accurate diameter can be achieved.
Reaming tools for steel construction can be used in milling machines, drill presses or by hand. Because of the extreme presence of friction, it is important to lubricate tool parts with sulfurized oil when reaming steel. In addition, reaming tools that are made from heat resistant material such as high cobalt steels or even tungsten carbide should be used. The actual time and position of a reamer during the process is calculated scientifically based on diameter of tool, number of blades on tool, feed rate, distance to next hole, and depth of hole. While a CNC machine milling would provide the most precise position and time a drill press is sufficient when the steel part is tightly secured.
Using reaming in steel construction can be expensive so it is important to consider when reaming is important and when it is not necessary. Reaming is mostly used when a typical structural bolt is not sufficient for the design safety required. A close tolerance bolt may be needed to avoid any slipping in the connection. In this case the hole will be made at the same diameter of the bolt and then reamed to create a close tolerance fit with the bolt. Cold work must be minimized when drilling initial hole so that when the reaming cut is made it reveal steel that is not work hardened. This is another benefit to reaming.