Announcement

Collapse
No announcement yet.

Setting The Head For A Compound Angle On A Knee Mill

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

  • Setting The Head For A Compound Angle On A Knee Mill

    Hello everyone. Just joined yesterday. I did a search and didn't have much luck finding anything on how to set the head for a compound angle on a knee mill. I know how to use a sine bar to set an angle on a knee mill but I don't know how to set a compound angle. Would I use a compound sine plate and a magnetic cylinder and indicate that? Any ideas or help sure appreciated.

  • #2
    I think Machinery Handbook has a section on setting compound angles. I have never done that and I don't think I want to as it is difficult for me to understand.
    It's only ink and paper

    Comment


    • #3
      If I understand you correctly, Yes a compound angle plate or sine it twice.
      Then use you indicator to dial it in.
      May I ask why you need a compound angle and why you can't place the Item at an angle?

      Comment


      • #4
        Originally posted by IOWOLF
        If I understand you correctly, Yes a compound angle plate or sine it twice.
        Then use you indicator to dial it in.
        May I ask why you need a compound angle and why you can't place the Item at an angle?
        Part is too big to mount at an angle. I guess the cylinder is overkill and all I need to do is to sine it twice or use a compound sine. Thanks for the help.

        Comment


        • #5
          Compound angles

          The easiest way to set a compound angle on a knee mill - any mill - is to model the part/s in 3-D in a 3-D CAD package and revolve/resolve the compound face/s into simple angles in the "X" and "Y" planes.

          If your mill has a "left"-"right" tilting head then set that for the "X" plane angle. If it has a "nodding" head, set that for the "Y" angle.

          If no "nodding" adjustment, solve for the "X" angle as before and set the head tilt. Also solve for the angle required to rotate the job on a rotary table so that the "Y" angle to be rotated on the rotary table can be set. Fix the job to the rotary table and set the head tilt and rotab rotation.

          To "get" this concept, just get a disc/coin in your hand, tilt and rotate it and it should become obvious.

          It is possible to work it out mathematically, but it is difficult and too easy to make a mistake.

          As said - use a 3-D modeling application.

          Even the venerable "Machinery's Hand-Book" "wimps it" and "cops out" by only having a very brief and cursory reference to it.

          If the job already exists then you can "search" for it by adjusting it on the mill to get the "X" and "Y" tilt angles.

          Be patient - very patient.

          An example of a compound angle in everyday life is the hip on a pitched roof where the two roof slopes intersect - normally at 45 degree in plan. JUst to make it "interesting", the two roof slopes can be different. But in each case the pitch of the hip (the compound angle) can be resolved to the individual roof pitches/slopes.

          Sketch it out in Isometric on a scrap piece of paper as that appoxiamates 3-D

          Be patient - very, very patient.

          Comment


          • #6
            Thanks for the response. I need some clarification on what you said.

            "The easiest way to set a compound angle on a knee mill - any mill - is to model the part/s in 3-D in a 3-D CAD package and revolve/resolve the compound face/s into simple angles in the "X" and "Y" planes."

            Make a solid CAD model so that I can visualize how the part is going to get cut? Use section planes to cut the solid CAD model?

            "It is possible to work it out mathematically, but it is difficult and too easy to make a mistake."

            You're saying it's better to visualize how the part will look using a solid CAD model and section planes so that there will be less chance of making a mistake/not getting what I want?

            "Even the venerable "Machinery's Hand-Book" "wimps it" and "cops out" by only having a very brief and cursory reference to it."

            Not my favorite book to read cover to cover.

            Comment


            • #7
              ah ha...se what you're up to

              my table don't do compound angles ..

              but if you got a Bridgeport ..you got the other angle right there ...

              so for instance a v8 head ....

              you would put the cylinder head on the tilting table .......
              mount dial indicator in the quill ......tilt table......untill dial indicator indicates face of head is dead on horizontal .

              them you would move the head of the Bridgeport to the other angle ..


              for valve guides if you don't have the gear .......you could put a closely fitting bar of metal in the guide ...then indicate off it to get that angle right ...on the Bridgeport head .

              all the best..mark
              Last edited by aboard_epsilon; 03-06-2008, 06:21 PM.

              Comment


              • #8
                Compound angles

                Originally posted by aboard_epsilon
                ah ha...se what you're up to

                my table don't do compound angles ..

                but if you got a Bridgeport ..you got the other angle right there ...

                so for instance a v8 head ....

                you would put the cylinder head on the tilting table .......
                mount dial indicator in the quill ......tilt table......untill dial indicator indicates face of head is dead on horizontal .

                them you would move the head of the Bridgeport to the other angle ..


                for valve guides if you don't have the gear .......you could put a closely fitting bar of metal in the guide ...then indicate off it to get that angle right ...on the Bridgeport head .

                all the best..mark
                Hi Mark.

                You've got the basics OK - very clever.

                Most compound angles that we deal with are really just 2 single/simple angles. Its mainly a matter of sorting out what and where they are and what you want to do with or to them. Its also a matter of what machines or tools you have and what their capacities are and whether the job can be fitted on the machine/s.

                I will go over some of the theory and applications as it might relate to the "real world" in the HSM in the next day or so. I will NOT touch the "heavy theory" stuff -I will keep it to the level of the HSM shop. I can trip myself up or get in over my depth (or most likely both) really easily, so its in my interest to keep it as simple as possible as well.

                I will use sketches and pics of some of my HSM shop tools as well.

                I will be interested in concepts. Specific examples will be avoided if possible but if necessary they can be dealt with as a normal discussion item as well.

                I will probably approach as I did with the "mill a sphere", "home-made sine bar", "rotab as a tilting table" etc. threads recently - and a bit of the "Solve for "X"" thread too.

                I will stick to the "applied" (ie "how to do it in the shop") approach and leave the theory out so far as I can.

                Comment

                Working...
                X