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Drill Bit Sharpening

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  • #31
    John, sounds like a CAM version of the Black Diamond type sharpener. That uses a collet and cam to grind by hand. See these go frequently under $100.00.
    I use the $20.00 fixture, but mount on my T&C grinder table so I can move in & out. I use a cup wheel so I'm not using the side of the wheel.
    I use my disc/belt sander to touch up drills.
    One thing I don't recall seeing mentioned here is a drill gage. If one of these is used to check point angle and center, the relief can pretty well be eye balled.
    Points can be split, or web releived carefully by hand using a cut off disc or thin disc wheel. Operative word here is carefully.
    Also, touch up drill before it gets to the point that it needs to be reground. Saves a lot of grief.
    Jim H.


    • #32
      I hand sharpen my tools and drills and don't feel like I need to take a back seat to anyone ...... unless I need a hole dead on and round. I think a high quality machine ground drill would be more accurate than what I can do by hand and would cut better once the machine learns "my grind" and how to grind on an abused grinding wheel. As our cutting tools become more exotic so will our sharping of tools.

      John, I think you are right on in your thinking about drill sharpening.


      • #33
        I suppose all this comes down to what you do with your drills. By this, I mean, do you produce precision holes to put bolts in? or are you drilling a rough hole for a fuel feed orifice??

        If I want an accurate hole (larger than say 1/8") I drill, then ream to size; if I want a rough sized hole I drill it because thats easier than punching. I keep a set of drills for rough(!) work, and a lovely set for nice jobs. I always clean them after use and put them back in the drill index in order. Any drills that get chuck damaged get dressed on the grind wheel, or replaced (but I can second Thrud's sentiments about an Albrecht chuck!)

        I know its difficult to sometimes get across in words what a physical action consists of, I'm sorry if my command of words is inadequate (guess thats why I'm an engineer and not a journalist or writer!!). As for grinding techniques, I have found that flat lands are less 'reliable' than the manufacturers curved land, some flat lands will 'drag' on the high rear edge next to the following flute. Flats can tend to 'dive' into material (especially ally), whereas curved lands perform as originals. I also 'back off' the trailing flutes, this has the effect of thinning the centre cutting edge. No need to do this on large diameter drills but its helpful on smaller drills especially when drilling stainless or titanium. Seems to me that its easier to follow the original land than to reshape the drill by putting flat lands on it!

        Be my guest! I suppose thats what this BB is all about ~ share info and thoughts between us all.

        John S:
        I like the idea, the advent of cheap CNC T&C's is long overdue; but it still makes sense to learn a 'hand art'. By the time a CNC T&C has been set up, programmed, and drill resharpened; the 'hand artist' is back on the machine 3 operations further on. Makes sense for a tool crib though, or for the home machinist to have a 'tool crib day' when he sorts out all his drills and cutters for a lick up.



        • #34
          Here is an idea for checking the grinding of taper shank drills (ie, drills with a centre in the shank end). I thought this method was well known, but met a machinist today who had not seen it, so...
          It is a way of checking that both cutting edges are the same height. Take a piece of flat steel, say 50mm x 5mm x 400mm long. (2" x 3/16" x 16" for those who think metric is a "pinko commie plot")drill a hole in one end and hang it on the wall next to your grinder. At the lower end weld or attach a point which sticks up ie bend a nail 90* and weld it to the flatsteel. Take your freshly ground drill, place the centre hole of the shank end over the pointy nail and scribe a line on the steel plate with the one of the cutting edge corners, Rotate drill 180* and scribe again, the second scribed line should overlay the first. If not, go back to the grinder.
          The steel plate can be covered with marking blue now and again.

          Also intrigued to see some recommend grinding drills on belts. I have found that what I call a linishing belt is not good for drills. A grindstone is better, but maybe you are talking about something else.
          By the way, a linishing belt (eg 900 x 50 wide) fitted to one side of a bench grinder has to be one of the most useful workshop tools I know of. You will never use a grindstone again (except for grinding drills!).


          • #35
            When you say "...back off the trailing flutes...", I'm visualizing a grinding operation similar to that of splitting a point. Am I close?
            Lynn (Huntsville, AL)


            • #36
              You have an excellent idea - a low cost cnc drill pointer. By taking it a step farther endmills and ballmills could also be done. I do not think a PIC could handle it math wise. And you would want to use microsteppers to smooth things out.

              Darex has a very expensive cnc repointer based on their drill holding collets - full automatic - big $$$$$.00

              I like the idea.


              • #37
                Please don't flame me or burn me at the stake!!
                Why hasn't any one suggested the TINKER Tool and Cutter Grinding Jig that Guy Lautard in BC,CA sells plans and castings for. Plans 32.50 and castings are 75.00.
                I have no experience with this machine/addon. But has anyone else here????

                Bill Adams
                IN NE WA ST
                Bill Adams
                IN SC WA ST


                • #38
                  A few of the guys have already built it and seem to like it - since they have not been complaining much...