Spring loaded zero backlash nuts on lead screws work ok for a while for light loads, but they do still wear out rather quickly and cause problems when they do. Some of the cheaper poorer designed ones will back off the spring when moving under load in one direction causing slop and lost motion. The better ones will bind up and get stuck when the screw gets too worn. They are no substitute for a good ballscrew. I work with a router that uses/used antibacklash lead screws. And we'd have to replace the screws and nuts every 2-3 years. After the manufacturer changed nut designs to a cheaper version, the life cut in half (but not the price). I had a ball screw made by Hywin for it about 12 years ago and it still works much better with tighter tolerances than the old leadscrew ever had and the one off ballscrew cost about half what the machine builder was charging us for their crappy lead screws.
Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -----Original Message----- From: Chris Albertson <albertson.ch...@gmail.com> Sent: Wednesday, April 14, 2021 12:15 PM To: Thomas J Powderly <tjt...@gmail.com>; Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> Subject: Re: [Emc-users] Worn Ball Screw? [EXTERNAL EMAIL] Be sure links are safe. On Wed, Apr 14, 2021 at 8:54 AM Thomas J Powderly <tjt...@gmail.com> wrote: > A few of the larger EDMs we built had 5meter leadscrews with dbl nuts, > That would fix the issue too. They use two nuts with a spring between them. It is really the same concept as oversized balls. In both cases, the balls ride on the walls of the groove rather than the groove's bottom. Some day 100 years from now the ball screw on my mill z-axis might become worn but the screw is always in tension as it supports the weight of the milling head and motor so the balls ride on only the lower side of the groove and it will not matter much if the balls or groove is worn down over the years. My 3D printer works the same way but with acme lead screws, only one side of the screw thread Is used, so there is never backlash when the direction of motion reverses. -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
