Homebrew PCBs

In a message dated 1/30/2007 10:15:24 A.M. Central Standard Time,  
stefan_trethan@... writes:

Does  carbide lose hardness if it gets too hot like hardened steel? I didn't  
bother to cool it much and it got  
orange hot quite  quickly.<<
ST!  No, WC does not anneal like steel does.   Getting it "red" does no harm. 
 It is back to just as hard when new, once  cooled, again.  The ONLY way to 
properly sharpen WC is with a DIAMOND  GRIT.  Some will tell you a "green 
wheel" will work (silicone grit), but  this is only SLIGHTLY better than 
aluminum-oxide (cheap grit).  The edge  will be "rounded" if you attempt to grind with 
ANYthing other than diamond  grit!  Too, you must not try to grind-off any more 
than 0.02-0.03 mm per  pass.  Else, you WASTE the grit on the diamond wheel.  
Takes some  experience; perhaps best if an old, skilled machinist (Schlosser) 
demonstrates,  once or twice!  You MUST have a fixture to hold the bit being 
sharpened, to  adjust each pass! Jan Rowland

 


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