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  • Sharpening fixture plans?

    Are there any plans available for a drill sharpening fixture?

  • #2
    A quick search for "drill sharpener plans" turned up about 6 different jigs ranging from simple holders which still need skilled touch to some degree up to a plan for a really fancy setup that requires you to make around two dozen parts. Have you done a similar web search and found those yet? If not then perhaps start with that and see if one of those will suit your needs?

    Which of the drill sharpeners you use will also depend on what sort of grinder or belt sander or surface grinder you have to use with the specific jig.
    Chilliwack BC, Canada

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    • #3
      Not trying to be an ass here, but try grinding by hand. It's not that difficult. A little practice is all it takes. Buy you self a good gauge to check your progress.
      Grab a couple of drill bits and go to town.

      Comment


      • #4
        To paraphrase a comment on this; "if you sharpen by hand you may get a result that works, but it will be neither correct, nor optimal as far as working."

        I sharpen by hand, especially big drills, and have hand sharpened down to 0.030" diameter, but I am aware that what I get is really only a better or worse approximation of the correct shape and performance.
        CNC machines only go through the motions.

        Ideas expressed may be mine, or from anyone else in the universe.
        Not responsible for clerical errors. Or those made by lay people either.
        Number formats and units may be chosen at random depending on what day it is.
        I reserve the right to use a number system with any integer base without prior notice.
        Generalizations are understood to be "often" true, but not true in every case.

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        • #5
          I hope to get around to making a sharpening set-up some day myself. Presently I sharpen drills larger then 1/8" by hand and can get good results but I have had a good bit of practice. For smaller ones, I mostly just buy new ones: name brands from good suppliers. I have done smaller ones by hand, but it is an exercise in getting lucky with two edges that more or less meet in the center. I do not do split point or other fancy grinds by hand.

          I do not plan to buy or make a sharpening device for just drills as I am satisfied with what I do now with them. But I do want to be able to sharpen other tools that I have and when I have this, I will probably look at sharpening drills with them too in order to be able to get split points and other geometries that can not be done by hand.

          There are three paths to this, IMHO. First you can make a facet type fixture to grind one, two, three, or even more facets on the end of a drill, end mill, reamer, or a lathe or lathe like tool. And second, you can make something that can sharpen the side edges of the end mills and reamers and other tools that have cutting edges on their sides. Oh, and then there are circular saw blades.

          I picked up a HF device for sharpening circular saw blades in a pawn shop and it can do an OK job if the wear is not too much. I do plan to make some improvements on it.

          For just sharpening the facets on drills, end mills, etc. I plan to make some fixtures for my bench grinders that are outlined in the "Workshop Practice Series" books. I can not remember the exact volume numbers but there were at least two which outlined how this was done. I can not find those exact volumes right now, but I think they may have been #s 38 and either 28 or 31. I have them somewhere and will check on the exact numbers and correct this post. The techniques and fixtures shown in these books would allow almost any drill bit geometry to be ground.

          As for the side cutting edges of end mills, etc. I have no definite ideas yet, but I do have a spin index that I may incorporate in at least a first attempt. But many say that an air bearing is really needed for this so that may or may not work.
          Paul A.
          SE Texas

          And if you look REAL close at an analog signal,
          You will find that it has discrete steps.

          Comment


          • #6
            Originally posted by aliva View Post
            Not trying to be an ass here, but try grinding by hand. It's not that difficult. A little practice is all it takes. Buy you self a good gauge to check your progress.
            Grab a couple of drill bits and go to town.
            It's not that difficult but you need a good wheel properly dressed so the drill bit doesn't bounce off it.
            occasionally I will sharpen one off the wheel on my T&C grinder. It's a 60 grit wheel. It runs much smoother than any bench grinder. But I only do this if I'm too lazy to take out my drill doctor.

            JL.....

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            • #7
              I believe that learning off hand sharpening isn't that difficult as I've done some myself. That said, I'm very sure that a well designed and built fixture would be yield better results. Every video I've watched on the subject ends with the drill being tested in a chuck of steel. If it is so fool proof why does everyone test the drill bit?

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              • #8
                I sharpen drills by hand on my belt sander. I have a good drill point gauge to get the angle and flute length the same on each side. Then a glance to insure "backing off" or clearance angles are close to the same and reasonable. After grinding I stand them up in a drill press vise with the cutting edges right and left in front of me on the bench. I stone the flute on the right then rotate the drill 180 deg. and stone the other flute, using a fine stone to polish out the marks from the belt. They generally cut well and usually very close to size. I have no use for a jig or Drill Doctor, or any other drill sharpening device.

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                • #9
                  I sharpened off hand for years. But I knew that at best getting a nice even end with identical angles and centered point was purely a matter of luck. It was a rare time when the drills would cut evenly like when new. They'd look fine to my eye but the real test is when they are put into a drill chuck on the lathe and both edges cut equal thickness full width ribbons of metal. And that is a rare thing on an off hand sharpened drill.

                  I'm sorry but insisting that off hand sharpening is optimum over a jig of some manner is like suggesting that we give up our graduated dials and DRO's on our machines and do all the work by eye and trial and error like we do with a wood lathe. The only reason we get away with it on drill sharpening is that the drills are like a pencil and we can simply try again until it's right.


                  Chilliwack BC, Canada

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                  • #10
                    I know how to hand sharpen a drill bit in theory but every time I have tried it, the results have been *less than spectacular* to put it mildly. I suck at eye- hand coordinationso I have to make do with either buying new ones or dragging out my Drill Doctor.
                    Location: Saskatoon, Saskatchewan, Canada

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                    • #11
                      the problem with drills is they are more complex than meets the eye. most fixtures/machines dont produce a correct grind. the question also is what is a correct grind. it doesnt take much to make a hole in a piece of steel, so a plethora of "contraptions" out there work, kind of. a multifacet grind is easy, but takes so much time its hardly worth is.

                      this is a usefull modification of the gadget everybody has in the bottom drawer that supposedly doesnt work. also a vid of what it takes to produce a real grind.

                      https://youtu.be/b-z1e8c8t0w?t=95
                      Attached Files
                      Last edited by dian; 02-04-2021, 04:59 PM.

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                      • #12
                        I keep one of these near my bench grinder. They use star wheels to break off the used abrasive and expose fresh.

                        https://www.zoro.com/dayton-grinding...UaAk56EALw_wcB

                        That is just the first one which came up in my search. There are many brands available.

                        PS: If you are looking for a smooth running bench grinder, I used a Dayton some years ago and it was very well balanced and would coast for two or three minutes after turning the power off. It was a pleasure to work with.



                        Originally posted by JoeLee View Post
                        It's not that difficult but you need a good wheel properly dressed so the drill bit doesn't bounce off it.
                        occasionally I will sharpen one off the wheel on my T&C grinder. It's a 60 grit wheel. It runs much smoother than any bench grinder. But I only do this if I'm too lazy to take out my drill doctor.

                        JL.....
                        Paul A.
                        SE Texas

                        And if you look REAL close at an analog signal,
                        You will find that it has discrete steps.

                        Comment


                        • #13
                          There is no single, "correct" grind. There are many different tip geometries that have been used and all of them work to one extent or another.

                          The one that I call a modified cone. This is probably the most common tip on commercially sold drill bits. I have seen excellent and really poor examples of this on new bits. When properly done, it works well but has a problem with the chisel point that requires brute force to work and can walk off center.

                          The two facet grind. This is just that; grind one facet at an angle, rotate the bit 180° and do the other edge in the same manner. This can work as well as, but no better than the modified cone. You must be careful to have clearance all the way to the rear edge of the flute and it has the same chisel point as the modified cone. And insuring this clearance requires a larger clearance angle just behind the cutting edge so that edge is weaker and will wear down faster than the modified cone.

                          The split point. This is not a unique grind, but an add-on for others, like the modified cone or two facet grinds. It eliminates the chisel point, replacing it with two edges that cut all the way to the center. This is probably the most popular of the improved drill grinds.

                          Then there are four and even six facet grinds. This allows the primary relief angle, the one just behind the cutting edge, to be smaller, producing a stronger cutting edge. The additional facets are present to ensure that there is sufficient clearance for the remainder of the area between the primary facet and the back edge of the flute. The split point feature can be added to them.

                          Those are only the most popular ones that I am aware of. I am sure there are others or other variations of the ones I mentioned.

                          Another word on the split point: the split point grind automatically (accidentally?) helps ensure a sufficient clearance at the rear area of a flute. So, if it is going to be employed with a two, four, or six facet grind, you may not even need the second or third pair of facets. I really like the split point feature.



                          Originally posted by dian View Post
                          the problem with drills is they are more complex than meets the eye. most fixtures/machines dont produce a correct grind. the question also is what is a correct grind. it doesnt take much to make a hole in a piece of steel, so a plethora of "contraptions" out there work, kind of. a multifacet grind is easy, but takes so much time its hardly worth is.

                          this is a usefull modification of the gadget everybody has in the bottom drawer that supposedly doesnt work. also a vid of what it takes to produce a real grind.

                          https://youtu.be/b-z1e8c8t0w?t=95
                          Paul A.
                          SE Texas

                          And if you look REAL close at an analog signal,
                          You will find that it has discrete steps.

                          Comment


                          • #14
                            Originally posted by challenger View Post
                            Are there any plans available for a drill sharpening fixture?
                            Well since you asked about plans and not should I learn to hand sharpen drills, here is You tube video of the 'Duplex' grinder based on the Potts grinder.
                            Twist drill sharpening jig - model engineer plan - YouTube
                            ^Shouldn't be grinding on the side of a regular wheel though, he should be using a plate backed wheel for that.


                            There are plans in the video or right here.
                            Dropbox - Drill sharpening - Simplify your life

                            There was a excellent 50ish page article by J. Hugel on drill geometry and why most grinders don't work or work well.
                            I downloaded it off the web years ago, but can't seem to find it now.

                            Edit, I found it.
                            Microsoft Word - Instructions-7Full (model-engineer.co.uk)
                            Last edited by cijuanni; 02-04-2021, 09:19 PM.

                            Comment


                            • #15
                              Originally posted by Paul Alciatore View Post
                              I keep one of these near my bench grinder. They use star wheels to break off the used abrasive and expose fresh.

                              https://www.zoro.com/dayton-grinding...UaAk56EALw_wcB

                              That is just the first one which came up in my search. There are many brands available.

                              PS: If you are looking for a smooth running bench grinder, I used a Dayton some years ago and it was very well balanced and would coast for two or three minutes after turning the power off. It was a pleasure to work with.




                              I've had one of those for years. It does an OK job. When I do dress my bench grinder wheel I take the grinder outside. Never do that in the shop as I don't have any dust collection system hooked up to it.

                              I always wanted to make a cross slide fixture that I could clamp to the bench grinder where I could mount a diamond nib on it and run it across the wheel. Maybe my next project.

                              JL............

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