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Tool for making or sharpening Phillips screwdriver tips

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  • #46
    That might be OK, but it would create an angle at the tip instead of the straighter portion of the cut that seems to be the norm. That shape could be created and sharpened using just a square file. I thought perhaps that might be the "Reed and Prince" or "Frearson" drive, but that has an even sharper profile which is a cross shape that has the same width slots for all sizes, so any driver can be used on any screw (although not ideally).


    By The original uploader was Doodle77 at English Wikipedia.Later versions were uploaded by Sakurambo at en.wikipedia. - Transferred from en.wikipedia to Commons., Public Domain, https://commons.wikimedia.org/w/index.php?curid=2821283

    You might have a "point" about grinding back the tip a "bit" to sharpen it. Good "tip"!

    http://pauleschoen.com/pix/PM08_P76_P54.png
    Paul , P S Technology, Inc. and MrTibbs
    USA Maryland 21030

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    • #47
      It depends a bit (!) on what the problem is with the driver. The usual condition after long use is that the entire end gets rounded back, so that the edges shown in your post get to be blunted, and the sides approaching them are worn to a slope, often for some distance back, perhaps 0,060 or so in severe cases. In that condition, they "cam out" at a low torque.

      If worn that far, then "sharpening" might be a "because I want to" task, and less "practical", given that screwdrivers are available without great cost, and replaceable tips are quite cheap, if you can use them. The equipment to "sharpen" would likely be more expensive than a raft of new drivers.

      The only way to sharpen would be to grind back past the sloped section, and re-cut the flutes if necessary. Re-cutting would likely be needed, as the "wings" thicken in the "phillips" type shown above, and the "Frearson" would likely be worn far enough back to need re-cutting also. to

      With the Phillips shown above, the original angle that leads to the edge would need to be reproduced accurately so that the cam-out torque would be correct.

      The various types seem to have become hybridized to the extent that it is difficult to identify a "Pozidrive" (which works decently) vs a Phillips. The one labeled "Frearson" above is the type I find identified as "Phillips" the most.

      The most practical version would perhaps have been a very blunt tip, with the 4 "wings" coming down to almost a flat end. That would have been nearly a Torx as far as ability to drive, and resistance to camming out.

      Things that are "designed to fail" (in this case to "cam out"), suffer from the problem that they may work well when first made, and properly made, but if made less perfectly, or worn, they totally change their behavior.
      Last edited by J Tiers; 12-10-2019, 01:31 PM.
      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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      • #48
        Not sure if anyone has mentioned this.....back in the day (around 1975) there were three types of "Phillips" style screws. We had an ongoing job to assemble hardwood pieces. We started with regular Phillips head screws and matching bits in power screw drivers. We had the usual problems with bit slippage in the screw heads messing up the appearance of the exposed heads.

        Our local screw supplier suggested we try a variation of Phillips that was popular in Canada and the associated special bits (can't remember the name). Much improvement over Phillips.

        There was another one that came along about when we quit that particular job. Don't remember that name either.

        With both these Phillips variations you were somewhat limited in sources. Since they were so much better grip-wise than regular Phillips the manufacturers defaulted to double start threads as the standard for quick driving. For us the double starts ran in too fast without enough control of depth as a single start.

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        • #49
          DR, I wonder if you tripped over a source for JIS which might not have been properly identified?

          I also wonder if drywall screws are not a bit of a special case? I find that drywall screws fit the usual Phillips bits more snugly and don't seem to cam out as readily as regular shiny style Phillips screws.

          EDIT- I now wonder if the drywall screws and most commonly found "Phillips" bits are not in fact the Reed and Prince or Frearson bits and screws. The curved shape vs straight taper shown in the drawing above is far more common on the tips.
          Last edited by BCRider; 12-10-2019, 10:36 PM.
          Chilliwack BC, Canada

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          • #50
            Originally posted by BCRider View Post
            DR, I wonder if you tripped over a source for JIS which might not have been properly identified?

            I also wonder if drywall screws are not a bit of a special case? I find that drywall screws fit the usual Phillips bits more snugly and don't seem to cam out as readily as regular shiny style Phillips screws.

            EDIT- I now wonder if the drywall screws and most commonly found "Phillips" bits are not in fact the Reed and Prince or Frearson bits and screws. The curved shape vs straight taper shown in the drawing above is far more common on the tips.
            Frearson/Reed seem to have sharper tip and even more taper than Philips so I don't think that the drywall screw heads are Frearson/Reed.

            I think drywall screws are just made with tighter tolerance. Heads are also hardened and won't deform nearly as easy. And the black coating has possibly more friction than bright zink.

            Location: Helsinki, Finland, Europe

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