Drill Sharpeners - Page 3
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  1. #41
    Join Date
    Aug 2005
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    Toronto
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    At work I do them by hand, up the 3 1/2 inches on a belt sander. Not a single fabricator knows how to sharpen one so they call me down to do it. Funniest one was when they ground clearance angle in the wrong direction...so again the much disdained "hobbyist" machinist as to come down from the office and fix it.

    That's fabrication with loose tolerances. For machining, hand grinding works but its is nicer to have greater precision. I can't eyeball a hand sharpening to get a drill that drills with a few thou....but I can with a tool grinder. No, we're not drill to thou's, but its better knowing what size hole you get than not, especially if say the next op is reaming.

    For down to #80 I have the small christen grinder, a beautiful machine with a microscope so they get set up perfectly. For larger I use the a V block thing I design and made, complete with a micrometer rest. With different extensions It'll do about any length of drill and works on a T&CG or surface grinder. The hard part is how to hold the drill - with the steep helix of the land, you need a long reference for it to rest against solidly - this is why collets often don't work well on larger drills. Anyway this thing has proven to work really well on any size I can fit in the V. The block is hardened and ground and the length stop and micro rest are locked with split cotters








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  3. #42
    Join Date
    Dec 2012
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    AUSTRALIA
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    The four facet method is an improvement on the old guy in the toolroom with coke bottle glasses who gets drills 1/8" off centre,but is no substitute for the requirement of correct rake and clearance over the whole edge .....maybe I should cancel scrapping my Herbert Hunt and give it another chance ,now Ive got a lot more time to play around with it......Last time I used it there was no net ,and no ebay ......so maybe Ill have a go at getting the setting bushes .....it needs a 6 jaw chuck too,to get away from morse taper holders ...be nice to grip the bits on the flutes.


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