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Extra long ball screw

Barnes Industries has made some of the longest ball screws in the machine tool industry. The Daniluk Corporation, Oklahoma City, OK contracted Barnes to build a custom-made 56 foot long ball screw with a rotating ball nut assembly for a large Giddings and Lewis horizontal boring mill. The traveling boring mill head was originally driven by a rack and pinion and was retrofitted to a ball screw drive using a 4 inch diameter screw x 56 foot long. The screw was supported in several areas to eliminate sag and improve overall accuracy. The project was completed in 1998 and is still in service today running two shifts, 6 days a week.

The ball screw was originally manufactured in two pieces and permanently joined together by a specially engineered process. We keep an inventory of hardened and ground 40 foot long bars up to 6 inch in diameter, in stock at all times in order to expedite delivery of large ball screws.

The bar was centerless ground on one of the longest bar-feeds in the Midwest holding a roundness of .0002 inches over full length.

The screw thread raceway is precut in the hardened state and then precision ground in one of the five Matrix 70 external thread grinding machines.

Barnes Industries can manufacture ball screws up to 70 feet long by this special process with the shortest deliveries in the industry. Contact our sales department to see how Barnes can help with your custom ball screw needs

Product Description	New Extra long ball screw assembly, 4.0 inch diameter by 56 feet long.
Capabilities applied, processes	Joining extra long bars by special process; 40 foot bar and 16 foot bar joined together
Tightest Tolerances	Major diameter of screw is centerless ground to a roundness of .0002” in 56’ length
Material Used	AISI 6150 HR, heat treated and centerless ground in 40 foot lengths-on the shelf, ready for processing
Lead Requirements	Screw lead adjusted during thread grind to compensate for screw stretch Less than .0005 inch/foot lead error after screw is stretched Screw stretched to compensate for sag and thermal growth
Screw supports	Screw sag in long shaft eliminated by retractable screw supports
Thread Grinding Requirements	Large Capacity Matrix 70 thread grinding machine used Extensive steady rest support required Accurate hook-ups between thread ground sections Solid outboard supports for length outside of thread grinding machine Continuous thermal control during grind operation
Application assistance	Engineering assistance available Retrofit from rack and pinion drive to ball screw drive Ball screw load and life calculations Engineered reliability
Industry for Use	Machine Tool
Delivery Time	10-12 weeks Expedited Service Available
Delivery Location	Oklahoma
Project Scope	Design and Build a long ball screw with a rotating nut assembly to replace the rack and pinion drive on a large Giddings and Lewis horizontal boring mill.