Announcement

Collapse
No announcement yet.

Indexible Boring Bar Advice Needed

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

  • #31
    Originally posted by Bented View Post

    Boring head for small holes like so.

    https://www.ebay.com/itm/25437651093...xoCI2UQAvD_BwE

    I am not suggesting that you buy such a tool, this is merely the first picture that appeared during a web search that answers your question.



    I see what that one does, very nice. The one I asked about had a very small dial @ 2-3 inches up the bar from the cutter. Of course I can't find a picture of that right now.

    Don't think I'll ever have one of those, but this was on the shelf next to the Bridgeport head, thought It might be fun to try. Ericson Tenthset.

    Click image for larger version

Name:	Ericson Tenthset Boring Head.jpg
Views:	67
Size:	654.7 KB
ID:	1972118

    Comment


    • #32
      Originally posted by BCRider View Post
      Oh, the grinding wheels. I think you'll find that 120 is pretty fine. Wheel grits cut a lot more smoothly than sandpaper grits. I bought a 120 originally to use for my wood working chisels. But for grinding wheels 120 is almost super fine. So I found that for touch ups to edges it's fine. But for actual hogging new shapes out of tool blanks it's slow and the pressure seems to polish the working face and I have to freshen it with one of the diamond bars frequently. I wish I'd gotten an 80 grit instead if I were to have only one wheel. For a two wheel setup I'd go 60 for rough hogging and a 100 or 120 for the touchups to edges on existing tools.

      For stoning the edges on HSS tools for the ones used for the fine cuts or for the shear cut tool I did for my shaper I use a fine india stone. I've no idea what the equivalent grit number would be. But the fine india is still pretty coarse compared to the "hard arkansa" stones or the white ceramic Lansky stones I use for finer work. For lathe and shaper work I found that the fine india was dandy. The mirror like edges from a few more licks with the white ceramic didn't make the edge cut any smoother or last any longer but took about 4 times as long to make it look good.

      Again, hope that helps.
      The gray wheels on my tool bit grinder are labeled "medium" & "coarse". Coarse is good for initial shaping but I want to replace the medium one with a 100 or 120 fine for final finish, then use this india stone for touch up.

      Click image for larger version  Name:	India stone.png Views:	0 Size:	213.4 KB ID:	1972122
      Last edited by Spindle; 11-26-2021, 09:44 PM.

      Comment


      • #33
        Originally posted by Spindle View Post

        I see what that one does, very nice. The one I asked about had a very small dial @ 2-3 inches up the bar from the cutter. Of course I can't find a picture of that right now.

        Don't think I'll ever have one of those, but this was on the shelf next to the Bridgeport head, thought It might be fun to try. Ericson Tenthset.

        Click image for larger version

Name:	Ericson Tenthset Boring Head.jpg
Views:	67
Size:	654.7 KB
ID:	1972118
        Buy it, your quest for repeatable <.001" diameters will require such a tool for boring.
        You have a small part, as mentioned above, drill then ream this will very likely get you within the desired dimensions

        Comment


        • #34
          I did buy it, just need to make a shank. Can't find a 5/8-18 R8.
          I had high hopes for reaming & got perfect .9375 ID on the 3 reaming attempts, but the surface was ruined on all of them. 1 slow pass, only in 1 direction, oil flood, new Grizzly reamer. Once on the lathe, twice on the mill. No floating holder though. That reaming situation probably deserves a separate thread.

          Comment


          • #35
            Originally posted by BCRider View Post
            Oxford, if I'd had a QCTP at the time that's what I'd have done too. It really is the easy and obvious option.
            .
            If using endmills as boring bars is a common occurrence, a holder for the endmill wouldn’t be a bad idea in the QCTP holder (or a square 4 way).

            I would make it out of square stock though, set the endmill once and you can rotate the holder around when you need a fresh flute.

            Comment


            • #36
              Originally posted by oxford View Post

              If using endmills as boring bars is a common occurrence, a holder for the endmill wouldn’t be a bad idea in the QCTP holder (or a square 4 way).

              I would make it out of square stock though, set the endmill once and you can rotate the holder around when you need a fresh flute.
              Again, a nice and handy idea for for those with a QCTP. Or since most QCTP's come as part of a set which includes a boring bar holder perhaps make up an adapter bar similar to the one I did in the picture? The one on the left with the off center end mill just happened to fit perfectly with mill scale and all into the boring bar holder that is seen in the picture.

              In my case the end mills I'm using as boring bars are those which were badly dulled or chipped from use in the mill. I've got no way to sharpen them for further use as end mills. So regrinding them to serves now as single tooth end mills means that they can't be flipped over any longer either. But for those that might use a new end mill for boring the square holder is a pretty nice idea.

              But perhaps not so easy for many of the 4 way posts found on the mid and smaller size lathes. Here's why....

              4way posts have fixed height slots where the center height of the lathe axis is above the center of the slot so it can line up with the intended square shank cutting tools. In my case (I just checked) the 11/16 (.69") has roughly .16" between my tool height setting spacer and the top of the slot of my old 4way. So in my case I'd be limited to use of an end mill with only a 1/4" shank installed in a holding block with a very high position off center hole. Anything larger would not allow me to have the cutting edge at the center height of my lathe.

              This issue with the 4way, which was all I had at the time, is what led to making the shop made boring bar tool post and adapter bars seen in that previous post.



              Chilliwack BC, Canada

              Comment

              Working...
              X