Announcement

Collapse
No announcement yet.

New boring head problem

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

  • New boring head problem

    Hey guys, I'm still a newbe but I got a new 3" boring head from Enco ( made in China of course ) First hole I cut was over size. So I took my test indicator touching the back side of the boring head mounted in the mill, when I moved the micrometer adjudsment out on the borng head .010 the indicator measured .017, then i went to .020 on the head the indicator read .034. Is there another way to check this error out ? Or is the lead screw in the boring head messed up ? I'm totaly new to this, but on a boring head is one graduadtion radius or diameter ?
    BTW thanks for this BBS, it's just plain great information for old dummys like me
    Ted

  • #2
    Ted,
    I'd make the same measurement with a regular dial indicator, being sure it's placed parallel to the travel of the slidy part of the boring head. It sounds like the dial on the head indicates travel of the cutter, not bore size. My BridgePort boring head's dial reads direct on the diameter. Because my memory is so poor, I stuck a piece of tape inside the lid of the storage box with that information.

    Comment


    • #3
      Some boring heads are "2 for 1" others are "1 for 1", However , if your measurements are correct, yours is niether. In which case you will not be able to bore a correct size hole. I would recheck your travel measurements.

      Comment


      • #4
        Ted, I've seen boring bars that move on the radius and some that move on the diameter. Mine is marked on the side "1 Graduation is .001 on the Diameter" or something to that effect. If I'm unsure what it is I always take a light skim cut to clean up the bore. Then measure the bore. Then I adjust the boring head half of what I want it to take out, say .01. If it opens up the hole .01 then you know that it is marked on the diameter, if it opens the hole up .02 then you know it is marked on the radius. You do need to make sure and be parallel with the boring head axis when checking with an indicator like jdunmeyer said.

        One other thing. They won't always take exactly what you move them because of tool deflection and tool wear. So you kind of have to get used to them like any other tool by practicing to use them accurately.
        Jonathan P.

        Comment


        • #5
          Hi Ted ,make sure that the gib adjusting screws are snug. If your boring head has a lock screw try locking it and take up any backlash in the adjusting screw then set up your indicator as previously mentioned loosen the lockscrew move desired increment reset lockscrew and re test with indicator ,repeatability and reliability on my import boring head has increased dramaticly since I've been paying more attention to gibs and backlash.

          I hope this reads easier than it writes

          Comment


          • #6
            Open it up and measure the screw pitch. And count the divisions on the dial.
            ...lew...

            Comment


            • #7
              Back at one place I worked we had one that did the same thing. It had a metric pitched micrometer adjustment, even though it was stamped for inches. might be your problem also. check it out and send it back if it is.

              Comment


              • #8
                Originally posted by rbregn
                Back at one place I worked we had one that did the same thing. It had a metric pitched micrometer adjustment, even though it was stamped for inches. might be your problem also. check it out and send it back if it is.
                Hey I agree with that. It may be marked with inches but you can bet the screw thread is metric, since it comes out of China. Now, you are not going to easily join up a reading in inches with a thread of metric.
                I also agree that you should open it up and put a thread gage on it to settle the question.
                It sounds like going from .010 to .020 results in readings from .017 to .034. Each is double the value but unassociated values.......that is my reason for believing the problem is with having threads inside......pg

                Comment


                • #9
                  Pics

                  Any chance of putting pics of the calibrated dial that is attached to the screw?

                  What was the pitch of the screw? mm/inch will do.

                  The problem and the answer might be a bit more evident then.

                  There is no inch:metric ratio in the 0.017/0.010 that I can see - yet.

                  Comment


                  • #10
                    If at all possible

                    Anything that is bought from China should be disassembled, cleaned, deburred and properly adjusted prior to use.
                    Non, je ne regrette rien.

                    Comment


                    • #11
                      Thanks for the replys, I'm out of town at the moment, but when I get back I'll take her apart and check the screw pitch. As I recall when I moved it past .020 and beyound the readings where not just increasing by .007" every time, but some other odd amount. Here's the model I noticed it has "JAPAN" on the one shown in the catalog page, yeah right. But I don't have any problems with Enco, they at least make the hobby less of a pain in the wallet.

                      Comment


                      • #12
                        Adjusting boring heads...

                        If you want to adjust these Criterion style heads to a fine degree of precision, better than plus or minus .001, you need to use an indicator. This goes for any brand. I've got several brands, different sizes, and once past the roughing stage and I am trying to cut to print, I always get out the indicators. To bank on that little dial on the side is foolish. I do have one Criterion with the .0001 adjustment that I am comfortable going to .001 with, or maybe a little better, but they are rare and expensive. With a decent indicator and a little time, any of them can be made to cut to size.
                        James Kilroy

                        Comment


                        • #13
                          On deflecting, I run the head down twice before taking a measurement. It is a habit that has proved itself.

                          Comment


                          • #14
                            boring heads

                            If You Have One Of Encos Automatic Boring Heads It
                            Will Dadvance At Increased Amounts Each Time You
                            Hold The Advance Ring 2 Thou Adn Then 4 Thou And Then 6
                            Thou

                            Comment


                            • #15
                              I bet your spindle shaft is moving causing run out and a larger size hole. Use the spindle lock, snug not tight, while boring down

                              Comment

                              Working...
                              X