working with small diamter tools

working with small diamter tools

Home Forums Beginners questions working with small diamter tools

  • This topic has 10 replies, 7 voices, and was last updated 30 May 2016 at 19:35 by Dave Smith the 16th.
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  • #240468
    Dave Smith the 16th
    Participant
      @davesmiththe16th

      I have a dial test indicator and whilst rotating the dial the dovetail holder snapped off. More a case of cheap junk than heavy handedness. The threads on the holders shaft had a very loose fit and it would tighten up and you turned the outer rim. Cheap metal and a tiny contact area left from where the dovetail cuts into it, sure fire fail point.

      I thought i would make another holder, a larger aluminium bar would be better to start with, leaving some material left so it doesnt break again.

      That got me thinking how do you cut a <5mm dovetail slot in steel? High spindle speed and slow travel? Would you slot it then cut one dovetail at a time? Or would cutting both offer better stability?

      How would it differ between say a small sub 15mm piece of steel and then the same dovetail in a 100mm long piece?

      Thanks.

      #8140
      Dave Smith the 16th
      Participant
        @davesmiththe16th
        #240475
        Thor 🇳🇴
        Participant
          @thor

          Hi Dave,

          I understand I am not the only one that has experienced destruction of the dial dovetail. I made a new one in steel, used a small slot drill to mill a slot to the correct width and then used a small triangular file to file the dovetail part into each slot wall. Not perfect by any means but it worked for me, I have been using it for over a year without problems.

          Thor

          #240485
          Chris Evans 6
          Participant
            @chrisevans6

            I recently cut dovetails in cast iron when making my ball turning attachment. My HSS dovetail cutters are 30 degrees which was to much for the job so I used one from my woodwork router (brazed carbide) 14 degrees from memory.

            Run at around 1000 RPM it cut well with no visible cutter damage.

            #240493
            Jon Gibbs
            Participant
              @jongibbs59756

              This video might be of interest…

              **LINK**

              Jon

              #240507
              not done it yet
              Participant
                @notdoneityet

                Personally, I would likely be looking to replace the quick change dovetail fixings for a more conventional hinged alternative. Some of the more expensive cheap DTI's come with replaceable backs. Although I have a couple with dovetail fittings, I still prefer the normal eye and screw type as there are very few times I need to change heads on my mag bases.

                #240510
                Dave Smith the 16th
                Participant
                  @davesmiththe16th

                  Thanks, I have seen some of his video's but not that one. Thats ideal for a small holder, what would you do with a larger piece though say 60mm or 100mm long? Filing that maybe an issue?

                  Didn't we have an edit post button somewhere? Typo in my title and a few elsewhere i wanted to change but its appears to be MIA.

                  #240689
                  John P
                  Participant
                    @johnp77052

                    I too had one of these small holders break ,this is one of these
                    jobs where a Quorn grinder is very useful.
                    Seen here in the album Workshop and machines a small
                    dovetail cutter ground up from the shank of an old 1/4 inch
                    end mill ,diameter across the points .210 inch.

                    John

                    #240814
                    Dave Smith the 16th
                    Participant
                      @davesmiththe16th

                      I 3D printed a small block to test the size and after a bit of filing it fitted but an odd problem popped up.

                      Moving the lever towards me moves the needle to the right, move the lever away and sometimes it moves to the left and sometimes to the right?

                      Move the lever very slightly to the rear and the needle moves left for 0.2mm or 0.3mm (it varies) then the needle jumps and starts moving to the right?

                      Broken spring or something overshooting? Its not that old but a cheapy one. Contacted the seller and hoping they will exchange it.

                      Probably need to look for a better one. Proper brand

                      I still need a better holder though, if they do replace it the holder is likely to be just as rubbish.

                      X$M brand.

                      #240864
                      mark costello 1
                      Participant
                        @markcostello1

                        Metal shaper and some quality grinding time would make a small dovetail.

                        #240898
                        Dave Smith the 16th
                        Participant
                          @davesmiththe16th

                          Only seen the shapers on youtube, I think Tubalcain did one on the fast return stroke?

                          How would you shape a tool for this?

                          block.jpg

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