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  • Albrecht Drill Chuck/CNC machine

    Hi Guys,

    Not too long ago I bought an Albrecht Keyless Drill Chuck that was pre-mounted on an R8 stem. This was to be used on my CNC machine. I spent about $350.00 for the chuck and $75.00 shipping to Alaska. I had been told that Albrecht was a celebrated brand.

    I had milled a “starter hole” using a 1/8” dia end-cutting endmill that was being held in the quill by a 1/8” R8 collet. I removed the collet and installed the drill chuck which now held a 0.140” cobalt drill. The drill was not matching up with the previously milled hole. I removed the 0.140” dia drill and replaced it with a 1/8” dia drill. In no way was the 1/8” drill matching up with the 1/8” dia milled hole. The drill was a good 1/16” off center. I had to jog the X/Y step-motors until I matched the hole. Only then did I feel sorta comfortable in completing the 0.140” dia hole.

    After completing the 0.140” hole, I ran several test by first milling a 1/8” hole and then installing the drill chuck to test if the 1/8” drill would “drop” into the hole without interference. It was still a good 1/16” off center. I removed the chuck, reinstalled the collet and inserted the 1/8” drill in the collet. The drill matched the hole perfectly.

    I would have thought the drill bit, being held in the chuck, would have gone into the hole without interference.

    Q1 – Am I expecting too much of the expensive chuck regarding placement accuracy? Is this normal?

    Q2 – If accuracy should be much better than this, should the chuck go back to MSC or Albrecht factory for correction or replacement?

    In passing, the chuck has never been dropped nor hurt in any way. It’s always stored in the protective, padded container in which it was packaged and shipped. There are no metal chips in the chuck nor on the jaws of the chuck. All is very clean.

    All pertaining comments welcome.

    Thanks,
    Harold
    For those having fought for it, Freedom has a flavor the protected will never know.
    Freedom is only one generation away from extinction.

  • #2
    As well as being off center, the bit must runout a lot in the chuck also. You did not mention runout. Put a dowel pin in the chuck, turn the spindle manually and indicate it.

    Albrecht chucks are top of the line. The problem could be in the arbor just as easily as the chuck. Either way, runout is the way to check it.

    Comment


    • #3
      Originally posted by Sparky_NY View Post
      As well as being off center, the bit must runout a lot in the chuck also. You did not mention runout. Put a dowel pin in the chuck, turn the spindle manually and indicate it.

      Albrecht chucks are top of the line. The problem could be in the arbor just as easily as the chuck. Either way, runout is the way to check it.
      Hi Sparky,

      Thanks for your reply. Good to hear another say the chuck is a top line chuck. I am really thinking it's the arbor. Though I have not yet checked run-out, when the chuck and drill are spinning at 5000 RPM, these is no wobble in the drill. I would think that I would see some wobble in the drill or if it's really bad, the drill would actually bend at that speed.

      Harold
      For those having fought for it, Freedom has a flavor the protected will never know.
      Freedom is only one generation away from extinction.

      Comment


      • #4
        Keyless chucks are for drill presses. ER16's & ER32's are for mills. That's my story & I'm sticking to it!
        Milton

        "Accuracy is the sum total of your compensating mistakes."

        "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

        Comment


        • #5
          Originally posted by DICKEYBIRD View Post
          Keyless chucks are for drill presses. ER16's & ER32's are for mills. That's my story & I'm sticking to it!

          DICKEYBIRD:
          I was really considering the ER "thing". Thanks for speaking up.

          Harold
          For those having fought for it, Freedom has a flavor the protected will never know.
          Freedom is only one generation away from extinction.

          Comment


          • #6
            Originally posted by hwingo View Post
            Hi Sparky,

            Thanks for your reply. Good to hear another say the chuck is a top line chuck. I am really thinking it's the arbor. Though I have not yet checked run-out, when the chuck and drill are spinning at 5000 RPM, these is no wobble in the drill. I would think that I would see some wobble in the drill or if it's really bad, the drill would actually bend at that speed.

            Harold
            In an earlier post, you said it was 1/16th off center.

            If it's out that far, you should be able to see it wobble when turning slowly. It should also circle the hole that you want it to go into.

            If you do not see any wobble, then the logical conclusion is that the spindle is at a slant. The Albrecht is a long piece of equipment (mine is), so it would magnify any tilt of the head or spindle.

            Dan
            At the end of the project, there is a profound difference between spare parts and left over parts.

            Location: SF East Bay.

            Comment


            • #7
              Originally posted by hwingo View Post
              I was really considering the ER "thing".
              You will never regret going in that direction Harold. The extra grip, accuracy & length reduction is wonderful. I use them everywhere, not just on the CNC lathe & mill but the manual machines as well. For the little amount of money fairly good ones (CTC Tools) cost, they were life changing to me. The only time I use a regular chuck is when the tool has a hex or 3-sided shank.
              Milton

              "Accuracy is the sum total of your compensating mistakes."

              "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

              Comment


              • #8
                Originally posted by danlb View Post
                In an earlier post, you said it was 1/16th off center.

                If it's out that far, you should be able to see it wobble when turning slowly. It should also circle the hole that you want it to go into.

                If you do not see any wobble, then the logical conclusion is that the spindle is at a slant. The Albrecht is a long piece of equipment (mine is), so it would magnify any tilt of the head or spindle.

                Dan
                Dan, I'm actually concerned that my stepper motors may be out of whack or the arbor is off center because I do not see any wobble and it doesn't circle the hole. However, if I remove the chuck and replace it with the 1/8" collet, the drill drops into the hole thus it's on center. Am I making sense?

                Harold
                For those having fought for it, Freedom has a flavor the protected will never know.
                Freedom is only one generation away from extinction.

                Comment


                • #9
                  Originally posted by hwingo View Post
                  Dan, I'm actually concerned that my stepper motors may be out of whack or the arbor is off center because I do not see any wobble and it doesn't circle the hole. However, if I remove the chuck and replace it with the 1/8" collet, the drill drops into the hole thus it's on center. Am I making sense?

                  Harold
                  Yes, that makes sense. I think you are out of tram.

                  I'm assuming R8 collet, so a 1/8 mill, drill or rod will be an inch or two from the spindle nose. I'm also assuming that your Albrecht is like mine, 3 inches long (plus arbor).

                  As an example; If your head is tilted back 1 degree, how much further is the tip of the endmill from the column when it's 4 inches from the spindle nose instead of 1 inch?

                  Dan
                  Last edited by danlb; 03-04-2018, 12:15 PM.
                  At the end of the project, there is a profound difference between spare parts and left over parts.

                  Location: SF East Bay.

                  Comment


                  • #10
                    1 degree out of alignment equals 0.0524" position difference between a tool projecting 1" and a tool projecting 4", according to my calcs anyway.

                    The giveaway should be that every time you line up the hole with a drill in the collet and then replace it with the same drill in the drill chuck,and randomly rotate the spindle, the misplacement should be in identical in direction. I don't see how it can be a fault in the chuck or arbour without massive, easily seen at any speed, runout. Yes, once or twice I've managed to trap a small drill between 2, rather than 3 jaws of a large drill chuck, but the fact that I'd done it was immediately apparent when I switched on. If it was an issue with X Y positioning, presumably you'd see the table move, and anyway, you say it all lined up again when you changed back to the collet. It just has to be a head alignment issue, doesn't make sense any other way IMHO.
                    'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

                    Comment


                    • #11
                      Well I dread to do it, BUT, there seems to be no way around the fact that I NEED to check tramming before I do anything else.

                      Thanks guys for posting your thoughts regarding my problem.

                      Harold
                      For those having fought for it, Freedom has a flavor the protected will never know.
                      Freedom is only one generation away from extinction.

                      Comment


                      • #12
                        Well Guys,

                        Here's how the "cow ate the cabbage". I checked tram and my head had moved 0.030". I really don't know how that could have happen because the 4 bolts holding the head in position were REALLY TIGHT. Nevertheless, I re-trammed the head and I'm once again only 0.0005" off.

                        Do you think that 0.030" was enough to have caused my problem?

                        Harold
                        For those having fought for it, Freedom has a flavor the protected will never know.
                        Freedom is only one generation away from extinction.

                        Comment


                        • #13
                          Originally posted by hwingo View Post
                          Well Guys,

                          Here's how the "cow ate the cabbage". I checked tram and my head had moved 0.030". I really don't know how that could have happen because the 4 bolts holding the head in position were REALLY TIGHT. Nevertheless, I re-trammed the head and I'm once again only 0.0005" off.

                          Do you think that 0.030" was enough to have caused my problem?

                          Harold
                          Yes, it would have caused the problem. Look at post #10 where Richard has done the math to show that a barely out of vertical head will have a small error with the spindle retracted and a much larger error with the tool tip further from the spindle.
                          At the end of the project, there is a profound difference between spare parts and left over parts.

                          Location: SF East Bay.

                          Comment


                          • #14
                            Originally posted by danlb View Post
                            Yes, it would have caused the problem. Look at post #10 where Richard has done the math to show that a barely out of vertical head will have a small error with the spindle retracted and a much larger error with the tool tip further from the spindle.
                            My calculation gave an answer of 0.0698 but regardless, I see that could definitely be the problem. I'm not the best when it comes to math.

                            Thanks guys!!!

                            Harold
                            For those having fought for it, Freedom has a flavor the protected will never know.
                            Freedom is only one generation away from extinction.

                            Comment


                            • #15
                              As a follow-up question, I would like to ask the group about my method of calculating “how many degrees the head was off”.

                              I have an instrument that is secured in the collet having two, parallel dial indicators. This instrument is designed to be used to tram the head of a milling machine. I’m almost certain you know what I’m talking about.

                              The distance between the two dial indicators’ stems is 5.0”. I zeroed both indicators before lowering the quill. I SLOWLY lowered the quill. One indicator’s stem engaged the table well before the second indicator’s stem touched the table meaning my head had moved out of alignment from its previous tramed position. I carefully lowered the quill further until the second indicator’s needle just barely began to move (less than 0.0005”). The total distance of travel registered 0.030” on the first indicator’s dial.

                              On a piece of paper I drew a Right Triangle. I assigned capital letters (A, H, & X) to all three sides. “A” was assigned to the base of the triangle, “H” was assigned to the hypotenuse being the longest side, and “X” was assigned to the vertical leg of the triangle. “a” was assigned to the angle created by the intersection of “A” and “H” where “b” was the angle created by the intersection of “H” and “X”. I know that the angle between “A” and “X” is 90 degrees because this is a Right Triangle
                              I let “X” = 0.030” height of vertical leg i.e., (inches of travel), and “A” = 5.0” (distance between both indicator stems). My unknowns are “H”, “a” and “b”.

                              Since I know the values for “A” and “X”, using the Pythagorean Theorem I solved for “H” which equals 5.0000899”. Knowing the values for all three sides, I needed to find the degree angle for “a”.

                              Using a different formula, and knowing values for “A” and “X”, I derived the value for “a” = 0.34377 degrees. So it would *appear* my head was out of tram by 0.34377 degrees.

                              Would someone PLEASE check my logic, and then check my math, and then tell me where I might have gone wrong.

                              Thanks,
                              Harold
                              For those having fought for it, Freedom has a flavor the protected will never know.
                              Freedom is only one generation away from extinction.

                              Comment

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