Ruff Manufacturing Inc., a heavy steel fabricator and flame cutting shop in Farmington, Minn., was supplying a customer with parts that had a hole that was flame cut in 2.250-in. thick A36 plate. When the fabricator’s customer asked Ruff to supply a finished part, the company was faced with machining the bore to finished size.
At first, Ruff Manufacturing roughed out the flame cut bore by milling with helical interpolation, then drilling to finish size. Depending on the size of the hole, the flame cutting and machining process took 3 min. to 10 min. The helical interpolation and finishing process on a 2 in. bore took about 4 min.
To reduce cycle time and boost productivity, Larry Stenger, Allied Machine & Engineering Corp. (www.alliedmachine.com) field sales engineer, suggested using his company’s Revolution Drill to machine the bore. Stenger said that would eliminate the helical interpolation and finishing operations. The time to drill a 2.015-in. dia. by 2.250-in. deep bore with Allied’s R36 Revolution Drill with a length-todiameter ratio of 2.2 was reduced to 50 sec. — a reduction in machining time of more than 75 percent. The Revolution Drill has an adjustability of 0.200 in. on diameter, so Ruff Manufacturing could reduce tooling requirements with this tool to machine bores within its adjustability range.
Indexable Revolution Drills are available in diameters from 1.75 in. to 4.0 in., with 12 different holders and three lengths to 4.5-times diameter.