From: muratlanne@gmail.com   
      
   "Richard Smith"  wrote in message news:m1ecop1ofb.fsf@void.com...   
   ...   
   I liked the look of a "Myford ML7R" on sale locally - but you cannot win   
   'em all.  Timing can not work out.   
      
   I've been told - you really really want to have a cover for precision   
   machine tools if the workspace is mainly a welding and metal-fab. space.   
      
   Best wishes to you all and a happy Christmas,   
   Rich S   
      
   ----------------------------   
      
   I'd look at the diameter and length of parts of the ore processing equipment   
   you might be building or repairing. My 10" diameter capacity lathe is too   
   small to refinish its own speed reduction pulley, or my brake drums and   
   rotors.   
      
   Unless you need to turn long solid rollers a lathe with some bed wear might   
   be acceptable. Usually the tailstock end has less wear and could turn each   
   half of a roller or thread the end of a shaft. My little lathe had over half   
   a mm wear in the ways near the chuck which didn't affect the small tools I   
   made with it.   
      
   The spindle bore is important when turning the ends of long shafts to fit   
   salvaged or rebored pulleys or gears. The slowest turning, highest torque   
   shaft on my sawmill calculated to 1" OD for mild steel fatigue life at 10HP.   
   That happened to be right for the metric chain sprocket I turned and splined   
   the shaft to fit.   
      
   The precision slides are bare steel. Machines left outdoors rust quickly, I   
   was lucky with the surface grinder because its ways are shielded from   
   grinding grit (and rain) and it could clean up the top of its magnetic   
   chuck. I still had to buy or make some replacement parts.   
      
   A lathe and mill are necessary, a surface grinder not so much but for $100 I   
   couldn't resist. It's probably saved several times its cost by resharpening   
   high quality endmills and large taps I bought dull and cheap. For me the   
   other essentials are a horizontal bandsaw and a bench grinder which shapes   
   and sharpens HSS lathe bits, my old, slow, worn lathe isn't happy with   
   carbide. The vertical mill is a fine drill press. Many have found the 4" x   
   6" bandsaw too troublesome and bought larger though mine is OK with some   
   changes. The 4x6 with a very coarse blade cuts 150mm (6") square timbers   
   neatly enough to expose the cut ends in a retaining wall.   
      
   I also have a horizontal mill which is less versatile but more rigid and   
   cuts considerably faster, and an abrasive chop saw for harder steel such as   
   rebar and tubing too thin-walled for the bandsaw until I found a 32 TPI   
   blade. A belt sander is handy for deburring sharp edges, a small portable 1"   
   x 30" model is enough for me and claims no permanent bench space, like the   
   chop saw (and often the bandsaw) I use it outside.   
      
   A 4 jaw lathe chuck will do everything, including hold a smaller chuck that   
   grips small rods or even a drill chuck for very fine work. Centering a shaft   
   in one is slower but more precise than a 3-jaw, especially a worn one. Part   
   of my qualification for optical work was showing I could center a 4-jaw to 1   
   micron, another was hand writing my name 0.5mm high. I can carve straight   
   strokes but not curves 0.1mm high, to label an IC bonding pad on the silicon   
   wafer.   
      
   1 micron is 0.4 divisions on an indicator graduated to tenths of 0.001". I   
   have a B&S BesTest graduated to 0.00005", 1.25 microns, $25 at a second-hand   
   tool store.   
      
   5C collets are very nice, partly to avoid the danger of spinning chuck jaws.   
   You need only the collets for standard sizes of rods and shafting. Work held   
   in them can be moved between the lathe and milling machine for indexed cuts.   
   My small 3, 4 and 6 jaw chucks are on 5C mounts for that purpose.   
      
   The lathe makes circular and rotating parts, power transmission, the mill   
   sliding or stationary ones, the frame. A lathe can be rigged to cut keyways,   
   flats on small parts or splines before you find a mill. Either can cut   
   mathematically defined curves or tapers by making an X-Y table with a   
   spreadsheet and then filing to the bottom of the cut marks.   
      
   A digital readout isn't essential especially for one-offs and repairs. My   
   home machines don't have them, I measure how far is left to go and cut most   
   of it by the graduated dials. This minimizes the effect of wear and shows if   
   I need to resharpen for final surface finish.   
   jsw   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)