Announcement

Collapse
No announcement yet.

Drill sharpening jig question

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Drill sharpening jig question

    So.... this winter I plan on building a drill sharpening system. Ive been wanting to do this for awhile and will finally have the time. After researching a few of the different types I seem to have narrowed the design down to 2 types. The first uses a rotational motion to sharpen the bit. Kinda like the drill dr but in a more vertical position. This type produces a convex / rounded profile on the bit. The other is one moves the bit in a linear motion like the tormek system. Anyone have any advice as to which method would be better. My initial thoughts are to build it like the tormek system. This would allow me to grind a split point multi angle bit much easier... Plus I could adapt for straight blades / end mills and such. My concern is that I just dont see many bits from the factory ground like this. This makes me wonder if there are any pros and cons between the two

    Any thoughts??

  • #2
    I thought about it also. Decided to work on a multi facet type jig. Am to the point of testing the concept with a crude but workable unit. Will follow your thread to see what comes up.
    Jim

    Comment


    • #3
      I have to agree with Jim, a multifaceted type jig is more versatile. The split point style grind is very desirable. And there are at least a half dozen other types of tips that it can do.
      Paul A.

      Make it fit.
      You can't win and there is a penalty for trying!

      Comment


      • #4
        Good worthy ideas but why not practice and become proficient in free/off-hand drill grinding. It might take a while and needs relatively frequent practice to keep your skill-set up to date.

        Its a very satisfying feeling when you get it right.

        Same applies to free/off-hand grinding of HSS tools for lathes and fly-cutters etc.

        I was taught to "hand" grind" tools as an Apprentice - 60 years ago - and I still use it as my default/"go-to" method even though I have adequate tools to do it on my pretty good range of specialist grinders.

        Comment


        • #5
          A reasonable-looking design was written up in the magazine that just happens to sponsor this site. Last year maybe. recently in any case.

          A 4 facet sharpener with point splitting.

          Bound to work a hundred times better than the stupid Drill Doctor that wears out after a few drills
          1601

          Keep eye on ball.
          Hashim Khan

          Comment


          • #6
            One consideration would be the range of bits you're going to sharpen. Cloning a darex would work for most bits up to 1/2" I'd rather have a Stirling type drill grinder for anything bigger.

            Comment


            • #7
              Originally posted by J Tiers View Post
              A reasonable-looking design was written up in the magazine that just happens to sponsor this site. Last year maybe. recently in any case.

              A 4 facet sharpener with point splitting.

              Bound to work a hundred times better than the stupid Drill Doctor that wears out after a few drills
              Do you know if its possible to get back issues ?

              Thanks

              Comment


              • #8
                Originally posted by oldtiffie View Post
                Good worthy ideas but why not practice and become proficient in free/off-hand drill grinding. It might take a while and needs relatively frequent practice to keep your skill-set up to date.

                Its a very satisfying feeling when you get it right.

                Same applies to free/off-hand grinding of HSS tools for lathes and fly-cutters etc.

                I was taught to "hand" grind" tools as an Apprentice - 60 years ago - and I still use it as my default/"go-to" method even though I have adequate tools to do it on my pretty good range of specialist grinders.
                Well, I do agree that having the ability to hand sharpen a bit is a skill any wannabe machinist like myself needs to have. Its my opinion though that no one no matter how good they are or how much they practice can sharpen as well as a machine designed for the task.

                Plus it gives me something to build lol

                Comment


                • #9
                  Originally posted by Axkiker View Post
                  Do you know if its possible to get back issues ?

                  Thanks
                  I believe the article J Tiers is referring to is "A Four-Facet Drill Sharpener" by John Moran. It ran in The Home Shop Machinist issues Jan/Feb 2012 and Mar/April 2012. Back issues are available by calling 800-447-7367.
                  George

                  Comment


                  • #10
                    I pre-grind badly dulled bits by hand grinding, then finish off with a precision, dedicated drill grinder. The reason is I don't want to waste the expensive CBN wheels roughing down a bit.

                    Learning the geometry of a correctly sharpened bit is worth doing. Trying to accurately sharpen bits by hand to drill as on size as possible seems to me to be wasted effort. If anyone claims to be able to hand grind to the accuracy of a good factory grind then I suggest they probably don't need measuring tools to machine to .001" accuracy either.

                    Comment


                    • #11
                      Multi-facet grinds require multiple passes, one for each facet, so sharpening takes longer and drives the price up - that is likely why they're not common commercially. Split point drills are usually more expensive than conical points for this reason.

                      Overview info on the 4 facet sharpener presented in HSM is here:
                      http://www.gadgetbuilder.com/DrillSharp.html#Facet4

                      Cost to build is about $130 assuming you use the small Harbor Freight grinder, a modest cost CBN or diamond wheel and ER collets from CTC. And assuming a modest supply of scrap.

                      John

                      Comment


                      • #12
                        In many twist drills anymore, the two gullets will be found to have either
                        two different forms, and/or two different depths. Lax quallity controll in all but
                        the highest end manufacturers.

                        May as well get good at free-handing. Because with drillls like this a "perfect grind"
                        isn't going to do it. You'll test your grind, and drill as much as 3 times oversise
                        what would have once been considered an acceptable result.

                        To salvage the bit you'll have to grind a compensation.
                        Any douts on this, section the gullet on a suspect drill on a comparator.
                        index 180 and get out the vomit bag.

                        Comment


                        • #13
                          Learning to hand-grind drills is indeed an excellent skill. When grinding a drill, I was taught (in the apprenticeship by the old journeymen) not to "roll" the drill . Always "drop the taper end". Try two drills, one each way, and then compare them to a brand new drill. No contest. Good luck.

                          Sarge

                          Comment


                          • #14
                            JMHO, but I'd suggest just buying a good used Darex M3-5 and building your own accessories as desired. $2-300 for them is pretty common once you get past the insane craigslist and ebay $500+ price tags. My current one was $250 in literally "only used a couple times" in a home/hobby "sharpening" shop and included the BNIB accessories for oversize drills, spade drills, and quite a few other things that I have to attempt still.

                            Admittedly, Ive thought about building my own cnc drill sharpener to speed up the process with some sort of automatic loading/unloading, but that was after staring too long at the cnc sharpening centers at work and dreaming of owning a similar business. Reality I believe today tho is that drills are considered expendable by too many to be worth it.
                            "I am, and ever will be, a white-socks, pocket-protector, nerdy engineer -- born under the second law of thermodynamics, steeped in the steam tables, in love with free-body diagrams, transformed by Laplace, and propelled by compressible flow."

                            Comment


                            • #15
                              +1 to what sarge41 said, hand sharpening is a skill worth leaning.
                              +1 to justanengineer. Buy a good drill grinder and be done with it. It may not do 4 facet grinds, but are you running production? Can you live without it?
                              IMHO, small drills can be cheap enough to toss when dull, just picked up some less than full packs of new National, Barnes, Illinois, PTD, etc. , over 100 pieces, wire size drills, #40 through #60, at a tag sale, $20. I can't be bothered squinting through a loupe to align a drill in a jig for less than 20 cents. Drills 0.125 and bigger, that's different all together.

                              Comment

                              Working...
                              X