On Wednesday 07 May 2014 04:38:27 Erik Christiansen did opine: > On 05.05.14 04:48, Gene Heskett wrote: > > This one is currently only bolted to its work surface via its front > > feet, a 3/4" thick slab of formica covered MDF, which in turn is > > sitting inside the "don't let a tool roll off" lip around the edge of > > heavy duty tool box, on casters, and sitting on a floor with a > > noticeable sway, low in the center of a 12x16 shed. > > Gene, it can easily be bed twist. Some years ago, all I did to install > my Taiwanese 3/4 ton lathe was adjust the tailstock to cut parallel. > (I _assumed_ that the massive bed casting wouldn't twist, sitting on its > metal stands, on a "level" concrete floor.) > > But putting a cheap laser level across the shears, pointing at a wall > about 16 feet away, there seemed to be about 0.4mm (10 thou) twist > between over the 40" bed length. An inexpensive Chinese machine level, > with one division = 0.02mm/m, soon made the hair on the back of my neck > stand on end. (Instead of putting it across the shears, as in the books, > I laid it on the flat top of the cross-slide, and wound the saddle back > and forth. Rapid saddle traverse necessitated quite a few seconds wait > for the bubble to settle down.) > > Just by carefully adjusting one jacking screw at each end, i.e. turning > a few tens of degrees, I now have the bed ends parallel, with a bit of > twist in the middle, amounting to 5 scale divisions (0.1 mm in 1 m = > 0.013 mm across the 133 mm bed). That's a third of thou in the old > money, and it'll do me. Of course, I had to put the tailstock back after > that, to undo the kludge. > > I think the machine level was about A$180, so it's worth trying to > borrow one, since it's only used for about ten minutes. > > Erik
I hadn't though of the laser level & the spot on the wall, I'll give that a shot tomorrow. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Is your legacy SCM system holding you back? Join Perforce May 7 to find out: • 3 signs your SCM is hindering your productivity • Requirements for releasing software faster • Expert tips and advice for migrating your SCM now http://p.sf.net/sfu/perforce _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
