H & J Johnson wrote: > > >> My suggestion is to just replace the pinion as most of the wear is >> there. At some point it maybe necessary to replace the rack as >> well. >> Of course if the amount of engagement is adjustable there may >> well be a >> lot more service gotten out of the pinions as well. >> >> >> Doug >> > > Doug, this has been my MO for a couple years now but the Rack finally wore > to the point of point loading the pinions so I said enough.. I've got > replacement > Rack already in the shop so I'll use it but I won't be installing it again.. > next time it > wears out I'll have the parts here to upgrade to ballscrews. Over time the > increased > roughness of movement destroys the ability to get a decent surface finish so, > I'm > confident that the upgrade to ballscrews will significantly improve this over > the long run. > > Not to mention stepping up the o/a accuracy of the machine. > > Btw, the pinons are pressure loaded into the rack using a gas shock. It's > just enough > load to overcome the max seperation pressure created by the rack [to seperate > the pinon > from the rack] This take into account wear and any possible miss alignment > etc of the rack. > > It's not optimum but has worked thus far.. The ballscrew is a good upgrade > for me.. can't wait > to get it done :) > > J. Johnson > > > > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day > trial. Simplify your report design, integration and deployment - and focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > Sounds like you are working the butt of that machine, in which case it sure ought to pay for good lead screws. I belong to some lists of home boat builders. I would really like to build a router about 4ft x 16ft . I could cut out complete boat kits and in a home shop there would not be much overhead costs. Even if the machine were a bit slow it would still be worth while. I would likely use wrack and pinion drives or belt drives. I have even considered chain drives of course that would require a more often calibrating of the machine. I have also thought about building the machine from wood with metal ways at least for the bed. It would expand and contract as moisture changes but so would the wood I'd be cutting so that would likely be a wash. An accuracy of 1/32" in four feet would be really, really accurate for boat building. That would be 1/8" in 16ft would be very perceptible. This would require cutting all the lengthwise lumber and all the cross frames together so if there were expansion and contraction of the machine, frames and longitudinals would all match each other. I have a work shed 20'x 30' that is heated with a wood coal stove. I have a cnc bench mill and south bend lathe so I can cast and make at least some special hardware. Don't know if I will get this done but I like to think about it :-) We'll see! Doug
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