From: none@none.com99   
      
   On 6/26/2025 6:06 PM, Jim Wilkins wrote:   
   > "Bob La Londe"  wrote in message news:103kkic$3nnjj$1@dont-email.me...   
   >   
   > I've made a few parts to scribe lines and center punches.  I made a   
   > point of it after my son gave me an optical center punch set for   
   > Christmas one year.  I even have a couple height gages with carbide   
   > scribes for helping with layout, although one usually only gets used to   
   > measure tool heights to be entered into a CNC machine's tool table.  Its   
   > pretty scary when I bring that carbide scribe down on top of a 0.026"   
   > ball nose end mill to measure the height.   
   > -- Bob La Londe   
   > ------------------------------------   
   >   
   > I learned to creep up on damageable things while wiggling paper between   
   > the part and the height gauge or endmill. When the paper drags I have a   
   > few thousandths of safe clearance left.   
   >   
      
      
   Paper is fine, if you measure the paper.  I learned that right here on   
   this group.  Most quality printer paper is about .003, but it can vary.   
   Its also slow, and if your reference surface is wet or covered in oil   
   its even slower because it changes the paper or you must take the time   
   to clean the surface.   
      
   3 of the machines I currently have under power use repeatable quick   
   change tool holders.  Two more that are int he project phase also do.   
   Using a height gage or an electronic tool height setter (one machine) is   
   much faster even being careful with fragile tools, and I might argue for   
   me atleast more controllable and less likely to damage a tool in spite   
   of any trepidation.  On those machines I may only need to measure the   
   tool once or twice in the life of the tool no matter how many times I   
   take it out of the machine.   
      
   All of that being said, I make mistakes.  I don't know how many edge   
   finders I have destroyed by turning the handle or the MPG in the wrong   
   direction, or by forgetting to reduce the spindle speed before I hit the   
   start button.  I do sometimes find myself using paper on edges and when   
   it jerks out of my hand I advance the thickness of the paper and look   
   for a witness mark.  Paper is a good tool, but its far from the best tool.   
      
   FYI:  People say an edge finder is only good to about .003, but I find   
   with care and the .0001 step I have programed for the step increment for   
   my MPGs its repeatable to about to within a couple tenths of the   
   backlash of the machine.  I've used an edge finder to put parts back on   
   the machine when I didn't plan for it with a work stop.  Its still only   
   good to .002 to .003, but its the same .002 to .003 every time.   
      
   --   
   Bob La Londe   
   CNC Molds N Stuff   
      
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