Honestly I had a RF31 round column mill drill for quite awhile. Initially I bought it to help me convert my RF45 I CNC'd and honestly I WISH I had never sold it. It is a GREAT little benchtop mill and there are a bunch of folks who have CNC'd them with good results. There are of course some issues with the round column but there are work arounds that work well. If I had one here and did not already have a Cincinatti arrow 500 VMC here working I would consider CNC'ing the round column. A square column RF45 is a better choice probably but if I found another RF31 for a good price somewhere I would not hesitate to snap it up again. Peace
Pete On Fri, Jun 21, 2013 at 5:21 PM, Art Eckstein <[email protected]>wrote: > At 05:02 PM 6/21/2013, you wrote: > >I'm thinking about converting my jet jmd-18 mill/drill with round > >column, but thing that worries me the most right from the start is, > >if Z axis would be accurate enough. > > > >There is one solution by reversing quill spring so it is forcing > >axis all the time downwards and this way you get rid of backlash on > >worm gear, next thing is how solve problem with quill lock, which is > >meant to be used when quill is in desired position (height) so you > >lock it to increase stiffness (and accuracy) on Z axis. > >So did anyone here did any similar conversion and have a solution or > >suggestion for this? > > > >here is machine's pic: > >http://www.rustan.ru/sites/default/files/JMD-18F.jpg > > > I cnc'd my RF31 about 13 years ago and had the same concerns as you. > Instead of reversing the spring, I got rid of it and replaced it with > a needle thrust bearing and a cap to keep the pinion shaft from > moving in and out (yes, it did and cause some problems as it allowed > the worm wheel ride up and down on the worm enough to break the worm > wheel) and put a counter balance on it to maintain tension. > Then on the right hand side, I loosened the two socket head screws > that holds the fine down feed housing to the head and gently tapped > the housing to make a tighter fit of the pinion shaft to the rack (be > careful as you can do to much!) and finally, as I put my servo on the > fine down feed shaft, removed the chrome bezel and made a proper > sized spacer that is held in by the plate for my servo motor to > rigidly locate the worm shaft so it could not move in and out and > again contribute to backlash. OH and the quill lock is in a drawer > someplace. The servo maintains proper height. > > Has worked well for me all these years! > > Art > Country Bubba > > > > > > > >------------------------------------------------------------------------------ > >This SF.net email is sponsored by Windows: > > > >Build for Windows Store. > > > >http://p.sf.net/sfu/windows-dev2dev > >_______________________________________________ > >Emc-users mailing list > >[email protected] > >https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
