Re: [Emc-users] Oversized balls
On Sun, 17 Feb 2013 20:23:40 -0600, you wrote: If the rebuilder uses two different sizes then the smaller ones alternate with the larger, that way the smaller counter rotate to keep down friction. The load capacity decreases. Any other ratio defeats the purpose. Your right - I asked today and it seems they replace most balls with oversize and use smaller balls evenly placed to take up the gap. They said if the fingers that pick up the balls are broken, the nut is scrapped. They replace the tubes too. The screw is usually harder than the balls and often doesn't wear, if so it's just polished and cleaned. Steve Blackmore -- -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Oversized balls
A MFG of CNC Routers no longer in business use to buy cheap ball screws and re load with over size balls to make them appear more accurate. And at first they were, but they would in short order destroy the ballscrew. From: ed ate...@mwt.net To: st...@pilotltd.net; Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Sent: Sunday, February 17, 2013 6:23 PM Subject: Re: [Emc-users] Oversized balls Steve Blackmore wrote: On Sat, 16 Feb 2013 13:34:52 +, you wrote: Has anyone tried reducing the backlash in a ballnut by fitting oversized balls? If so, how did it turn out? Andy - commercially they don't replace every ball with oversize ones. Some do, some don't. They replace every n th ball with a slightly oversize one. If the rebuilder uses two different sizes then the smaller ones alternate with the larger, that way the smaller counter rotate to keep down friction. The load capacity decreases. Any other ratio defeats the purpose. It's a bit of a black art and the guys sort of do it by feel. Feel is the key, that and having a varied selection of sizes to try. I've seen a screw that was rebuilt by some company in the midlands and it was superb, and much cheaper than a replacement, but still out of my pocket. I did have a go doing all the linear slides on an Isel router, I replaced every 5th ball with oversize ones and replaced all the other balls with correctly sized ones and it worked great. Only having 1 of 5 oversize either loses rigidity with the correct size or greatly increases the strain on the individual balls and the contact points of the slide if you go oversize and go by feel That had had a hard life cutting ceramic and the dust had got in despite the fact the ways are covered and the inside was air pressurized in an attempt to keep the dust out. Steve Blackmore -- Ed. -- The Go Parallel Website, sponsored by Intel - in partnership with Geeknet, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials, tech docs, whitepapers, evaluation guides, and opinion stories. Check out the most recent posts - join the conversation now. http://goparallel.sourceforge.net/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- The Go Parallel Website, sponsored by Intel - in partnership with Geeknet, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials, tech docs, whitepapers, evaluation guides, and opinion stories. Check out the most recent posts - join the conversation now. http://goparallel.sourceforge.net/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Oversized balls
On 17 Feb 2013, at 00:47, ed ate...@mwt.net wrote: Is this a single nut? Some are doubles with shims between to set lash, they of course cost more. Yes, single nut. Some sort of double nut would have been nice, but it would cost me too much travel on that axis. -- The Go Parallel Website, sponsored by Intel - in partnership with Geeknet, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials, tech docs, whitepapers, evaluation guides, and opinion stories. Check out the most recent posts - join the conversation now. http://goparallel.sourceforge.net/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Oversized balls
On Sat, 16 Feb 2013 13:34:52 +, you wrote: Has anyone tried reducing the backlash in a ballnut by fitting oversized balls? If so, how did it turn out? Andy - commercially they don't replace every ball with oversize ones. They replace every n th ball with a slightly oversize one. It's a bit of a black art and the guys sort of do it by feel. I've seen a screw that was rebuilt by some company in the midlands and it was superb, and much cheaper than a replacement, but still out of my pocket. I did have a go doing all the linear slides on an Isel router, I replaced every 5th ball with oversize ones and replaced all the other balls with correctly sized ones and it worked great. That had had a hard life cutting ceramic and the dust had got in despite the fact the ways are covered and the inside was air pressurized in an attempt to keep the dust out. Steve Blackmore -- -- The Go Parallel Website, sponsored by Intel - in partnership with Geeknet, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials, tech docs, whitepapers, evaluation guides, and opinion stories. Check out the most recent posts - join the conversation now. http://goparallel.sourceforge.net/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Oversized balls
andy pugh wrote: Has anyone tried reducing the backlash in a ballnut by fitting oversized balls? If so, how did it turn out? Do you have backlash the full length or is the screw worn in the middle? Most can be reballed to reduce the slop but you must be careful that the OD of the ball does not bear, you want contact on the quadrants. How much backlash do you have now? I put new balls in my Well-Index X axis and it tightened it right up. Luckily the screw had very little wear. Ed -- The Go Parallel Website, sponsored by Intel - in partnership with Geeknet, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials, tech docs, whitepapers, evaluation guides, and opinion stories. Check out the most recent posts - join the conversation now. http://goparallel.sourceforge.net/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Oversized balls
On 16 Feb 2013, at 14:58, ed ate...@mwt.net wrote: Do you have backlash the full length or is the screw worn in the middle? Most can be reballed to reduce the slop but you must be careful that the OD of the ball does not bear, you want contact on the quadrants. How much backlash do you have now? Turning the pulley by hand between positions with the table clamped shows 0.08mm delta on the DRO. This is with brand-new parts, but no preload. RSW pattern nut. -- The Go Parallel Website, sponsored by Intel - in partnership with Geeknet, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials, tech docs, whitepapers, evaluation guides, and opinion stories. Check out the most recent posts - join the conversation now. http://goparallel.sourceforge.net/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Oversized balls
Andy Pugh wrote: On 16 Feb 2013, at 14:58, ed ate...@mwt.net wrote: Do you have backlash the full length or is the screw worn in the middle? Most can be reballed to reduce the slop but you must be careful that the OD of the ball does not bear, you want contact on the quadrants. How much backlash do you have now? Turning the pulley by hand between positions with the table clamped shows 0.08mm delta on the DRO. This is with brand-new parts, but no preload. RSW pattern nut. With that amount of backlash I would try some that were .1mm larger then check it again. Without knowing the pressure angle it makes it difficult to give a solid number. Is this a single nut? Some are doubles with shims between to set lash, they of course cost more. Ed. -- The Go Parallel Website, sponsored by Intel - in partnership with Geeknet, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials, tech docs, whitepapers, evaluation guides, and opinion stories. Check out the most recent posts - join the conversation now. http://goparallel.sourceforge.net/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
