Announcement

Collapse
No announcement yet.

Good, bad, and ugly - odd tools

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

  • Good, bad, and ugly - odd tools

    I have what seems to be a carbide milling bit with 5 flutes, but the size (including the shank) is 15/64" (and not 1/4" as I had thought it was). I remember buying it a long time ago to attempt some light milling, such as making a slot in a piece of phenolic, but when I returned to the industrial supply store where I think I got it, they no longer carried such items. I could find similar tools, but they are usually with four flutes, and 15/64" end mills have 1/4" or other more standard sizes. Here is a picture:



    That's the good. As for the bad and ugly, I found some drill bits that were part of a set of 13 that I bought for cheap when I was just a teen in the early 1960s. That was before there were cheap Chinese tools, and before "Made in Japan" meant high quality. I used them mostly for wood, but I also may have used them on steel bar and angle, using a 1/4" electric drill (remember when they were the norm?) Anyway, they seem to have been roughly ground from a chunk of rather soft steel, and no raised edge on the flutes, which probably accounts for the problems I remember having with them jamming and getting hot and breaking. My father, who had been a machinist, had a nice set of numbered drills, but they were "off-limits". Have a look:



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

  • #2
    Think that the milling bit is metrick. 15/64 is 5,953 mm

    Comment


    • #3
      Originally posted by spinningwheels View Post
      Think that the milling bit is metrick. 15/64 is 5,953 mm

      Hmmm - when I metrick I don't think he had any of those - when was the first time you seen him?

      Comment


      • #4
        When I met Rick, I didn't think he would manufacture a 5.953 endmill.
        Maybe Rick made a 6mm. ??

        Comment


        • #5
          Now you have me wondering if were all talking about the same guy???

          Comment


          • #6
            OK its metric, sorry English is not my first language

            Comment


            • #7
              Originally posted by spinningwheels View Post
              sorry English
              Nice play on words.

              Comment


              • #8
                It reads 0.2335" or 5.93 mm on my HF digital caliper. 15/64" is 0.2344. 6mm is 0.236". So it would be undersize for either.

                However, I used my old Starrett micrometer and it reads 0.2358", as does my dial caliper. I estimate the fourth digit.

                I'm surprised that the digital caliper reads that far off, and I have checked it previously. But I just now checked a piece of round tubing, and the micrometer reads 0.3767 while the caliper reads 0.3745. And I checked a sprocket that read 0.870" in the micrometer but 0.8675" on the caliper.

                So, it seems to be a "Me Trick" tool!
                http://pauleschoen.com/pix/PM08_P76_P54.png
                Paul , P S Technology, Inc. and MrTibbs
                USA Maryland 21030

                Comment


                • #9
                  Shanks are usually pretty close to "correct" or "marked" size, so no idea on that one.....

                  The drills without the flute relief are generally older, and/or maybe not intended for metal. The cutaway trailing part of the lands lessens the drag in the hole. Might be other reasons also.

                  As far as calipers, don't bother trying to read them to tenths. With a caliper that has a full turn per 0.1", you can usually trust it to a couple thou. The ones with 0.2" per turn, more likely 4 or 5 thou, mostly due to reading errors and zeroing errors, added to tilting of the jaws because this is a contact measurement, and there is a tilting force applied when they touch the part.

                  Then also, the pointer is thick and the graduations are rather fine in comparison. It's as much a "resolution" problem as it is a real "accuracy" issue. The basic accuracy of the device as-made probably takes that into account

                  We've had folks here claim better accuracy by reading the dial with a magnifying glass and interpolating. You DO get better resolution that way. But not better "accuracy".

                  There is no guarantee whatsoever that the basic mechanism justifies the resolution. Most likely it does not. The accuracy may be much less, so you can read to a tenth or two, but the pointer position may be "out" by 10x that much relative to the true dimension of the part.
                  CNC machines only go through the motions

                  Comment


                  • #10
                    Here is an ugly drill bit.



                    It came out of a pack of #10 jobbers bits. Does anyone know how drill bits are made?

                    Stu

                    Comment


                    • #11
                      Thats snagged at some point and wound the opposite way. Heres one I did personally using cheap drills in the mill...

                      Comment


                      • #12
                        I thought those might be some kind of new fangled ambidextrous drill bits.
                        Location: Long Island, N.Y.

                        Comment


                        • #13
                          The drill bits I showed seem to have been milled or ground in discrete steps to make the flutes, and then the diameter ground to size. The steel is very soft, and looks "grainy". I can scratch it with a screwdriver but not a paper clip.

                          Looking closely at the shank of the 1/4" bit I can see "Made in Japan". These were from the late 50s or early 60s, when that meant something much different from what it does now. I seem to remember some of them being sharpened backwards, but not with backwards flutes. I think I did manage to "untwist" one or two when they jammed.
                          http://pauleschoen.com/pix/PM08_P76_P54.png
                          Paul , P S Technology, Inc. and MrTibbs
                          USA Maryland 21030

                          Comment


                          • #14
                            Originally posted by Stu View Post
                            Here is an ugly drill bit.

                            It came out of a pack of #10 jobbers bits. Does anyone know how drill bits are made?

                            Stu
                            Clearly that is a bidirectional handed drill bit. It feeds the chips towards the center of the hole for better jamming and binding action. :P
                            Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                            Comment


                            • #15
                              It's a relic of the "mirror universe", where time goes backwards and the CCW rotation of that tool (which is made of anti-matter) fills the hole with chips. It's an "undrill", or "llird" to our Doppelg┘ćngers.
                              http://pauleschoen.com/pix/PM08_P76_P54.png
                              Paul , P S Technology, Inc. and MrTibbs
                              USA Maryland 21030

                              Comment

                              Working...
                              X