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Centering a keyway on a shaft, using horizontal mill

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  • Centering a keyway on a shaft, using horizontal mill

    Lots of downtime, so been watching as many machining videos as possible.
    Cutting a keyway on a shaft using a vertical mill, there is a neat "trick" where one, more or less, clamps the shaft down and moves the table back and forth under the spinning cutter and by careful observation, once the top has been taken off the perimeter of the shaft to the width of the cutter, you are centered (if you go past you judge based on having the same amount "extra" on either side of the cutter).

    Being a noob, I like this...no DRO needed, no wondering if the measurement you took was actually correct etc. etc.

    Is there a similar "trick" to be used on a horizontal mill?
    I assume you don't want to be going "back and forth" as that would put a huge side load on a horizontal cutter that it was not meant to take...I suppose you could to little cuts that just touch on the end of the shaft in a similar fashion as above and then just lock that axis? Somehow that does not seem quite the same thing though...and you run into problems if the shaft is longer than the table/table movement combo...

  • #2
    can you share the video?

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    • #3
      Originally posted by dian View Post
      can you share the video?
      Not sure which one the OP had in mind, but Keith Fenner demonstrates it from about 4:30 in this video, for example:

      http://youtu.be/rfBbzRJspac?t=4m30s

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      • #4
        accucacy is in the eyes of the beholder, i guess.

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        • #5
          Drop your cutter into the keyway of the mill table.
          Center it with feeler gauges. Raise up the cutter, and lay the shaft in the keyway and clamp. Done

          Rich
          Green Bay, WI

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          • #6
            The keyway can be cut the same way in a horizontal mill as in a vertical mill using an end mill into the side of the shaft instead of the top as on a vertical mill. By moving the table up and down the flat on the shaft can be made in the same way.
            If you are talking about woodruff key cutters, the only way I know to find center would be to use an edge finder, find the edge and move the table sideways half the diameter of the shaft plus half the diameter of the cutter. This could be accomplished with either a DRO or dials on the mill. Otherwise, if your T slots aren't damaged, Rich Carlstedt's method would work.

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            • #7
              I watched the video and wasn't impressed! The most accurate way on a vertical mill to get centre is an edge finder or even better swing a DTI betweeen the vice jaws and when you get 0-0 both ways you are centered. Best to put the edge finder or DTI in a collet chuck so they are roughly in the same place as the cutter will be height wise. On a horizontal just touch the cutter on the work piece diameter [ blue the workpiece for clarity and spin the cutter in reverse by hand], move over half the work diameter and half the cutter width and you should be good to go.
              Tony

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              • #8
                I use Tony's method. It has always worked for me. Horizontal or vertical. Bob.

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                • #9
                  Originally posted by firbikrhd1 View Post
                  The keyway can be cut the same way in a horizontal mill as in a vertical mill using an end mill into the side of the shaft instead of the top as on a vertical mill. By moving the table up and down the flat on the shaft can be made in the same way..
                  doing them in the horizontal mill means you don't have to use an end mill, which are a pita for keyways, you use a horizontal milling cutter. In the vertical my preference is a woodruff style cutter.

                  Russ, that methods works parallax and eyesight no longer like a 25 year old has me picking up edges rather than eyeballing
                  in Toronto Ontario - where are you?

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                  • #10
                    The answer for a vertical mill is to put a say 3/8" (0.375") diameter HSS tool bit in the vertical mill 3/8" collet.

                    Measure the diameter of the shaft to be keyed.

                    Bring the HSS up to just touch the side of the shaft to be keyed.

                    Set the "Y" dial to zero.

                    The centre of the 3/8" tool bit is now (1/2 x (diamater of shaft + diameter of tool bit)) = say "d" - away from having the centre of the tool bit positioned accurately over the centre of the shaft to be keyed.

                    Move the say mill "Y" a distance d.

                    The positioning the centre of a vertical milling over the centre of the shaft to be keyed is slightly different.

                    Measure the diameter of the shaft and the width of the milling cutter.

                    Bring the cutter (optionally rotating) in in "Y" to just graze the side of the shaft to be keyed.

                    The centre of the cutter is now ((shaft diameter + cutter width)/2) = (say) d2 - away from being over the centre of the shaft to be keyed.

                    Zero the "Y" dial.

                    Move "Y" a distance d2 to position the centre of the cutter over the centre of the shaft to be keyed.

                    Cutter depth of cut is identical for both a vertical and horizontal mill.

                    Set cutter depth of cut be raising the knee (on a knee mill) until it just grazes the shaft to be keyed.

                    Zero the knee (Z?) dial.

                    Lower the cutter and start the cutter - set heiht to zero and then set cutter depth for a single or multiple depths of cut/s.

                    Simple Shop Math and Geometry 101.

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                    • #11
                      What oldtiffie says is the only way I've ever done it on the horizontal mill (In the second example he gives - I think he said "vertical" in error). I might only add that for "the touch" you could use a piece of cigarette paper between the horizontal cutter and the workpiece till you feel it snag on the paper. Probably not that necessary though. Touching the work with the cutter should be close enough.

                      EDIT:
                      I also watched that video posted above. I've seen some of this guy's other videos and he seems to know what he's doing but for the life of me I don't know why he is using the method that he is using in that video to find the center of the shaft. Maybe he just doesn't want to swap collets for the edge finder? I think I could have changed collets and gone to an edge finder, found the center of the shaft and been well into my first linear cut in the time he took going back and forth with that end mill, and in the end he is relying on the cutter being centered by eye ??? I don't think so. Nope, nope, nopie nope.
                      Last edited by DATo; 01-24-2013, 05:12 AM.

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                      • #12
                        Originally posted by DATo View Post
                        What oldtiffie says is the only way I've ever done it on the horizontal mill (In the second example he gives - I think he said "vertical" in error). I might only add that for "the touch" you could use a piece of cigarette paper between the horizontal cutter and the workpiece till you feel it snag on the paper. Probably not that necessary though. Touching the work with the cutter should be close enough.

                        EDIT:
                        I also watched that video posted above. I've seen some of this guy's other videos and he seems to know what he's doing but for the life of me I don't know why he is using the method that he is using in that video to find the center of the shaft. Maybe he just doesn't want to swap collets for the edge finder? I think I could have changed collets and gone to an edge finder, found the center of the shaft and been well into my first linear cut in the time he took going back and forth with that end mill, and in the end he is relying on the cutter being centered by eye ??? I don't think so. Nope, nope, nopie nope.
                        As an apprentice I was taught the "touch the side of the shaft with the cutter" method or use a cigarette paper if you didn't want to mark the shaft. Always worked for me, but I'm anal anyway.
                        Clive

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                        • #13
                          Originally posted by Mcgyver View Post
                          doing them in the horizontal mill means you don't have to use an end mill, which are a pita for keyways, you use a horizontal milling cutter. In the vertical my preference is a woodruff style cutter.
                          No Doubt your method is better and easier, provided woodruff key cutters are available. The first portion of my response assumed the OP had access only to end mills or was asking only about them since the video he mentioned involved using end mills.

                          I don't want to hijack the OP's thread with the following question so if your answer is too far off topic to post here, let me know and I'll post in another thread. Here's my question:
                          Given your experience using woodruff cutters to cut keyways on shafts do you have problems with chips binding between the cutter and the cut edges of the keyway when cutting a long keyway? I haven't used one for anything other than a woodruff key. The woodruff cutters I have used don't appear to have much in the way of clearance on their sides. Given my limited experience with horizontal milling, I was under the impression that cutters used to cut a "channel" such as a long keyway needed to be side cutting as well, or have chip clearance along their sides.
                          Thanks in advance.

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                          • #14
                            Originally posted by clive View Post
                            As an apprentice I was taught the "touch the side of the shaft with the cutter" method or use a cigarette paper if you didn't want to mark the shaft. Always worked for me, but I'm anal anyway.
                            Clive
                            Got to agree with you. Edge finder or touching the rotating cutter to the side (with cig. paper between cutter and work) would be the proper method taught. Also don't know why he is shown using a grinder (angle or die), with the mill table serving as his worktable in several of his videos. Bad for the machine's ways.

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                            • #15
                              It is just a keyway in a shaft. There is no need to go to extremes of accuracy in setting up to cut one. I have seen a few of the Kenner videos and he is a very practical machinist in a for profit shop. His method, and a good eye, is more than accurate enough for a keyway. I didn't watch the vid, but I would be willing to bet that when he is doing this in real life, he gets it in one or two passes.

                              For a horizontal milling machine, touch off the side of the shaft, drop the table and move half the diameter of the shaft plus cutter width.

                              For the vertical mill, I usually use my wiggler and a steel rule for a straight keyway. For a Woodruff keyway, I touch the cutter off on the top of the shaft, lock the spindle, move off the shaft and either lower the spindle or raise the table half the distance of the shaft diameter plus the cutter width just as you would with a straight cutter in a horizontal mill.

                              I think one of the Lautard books describes a similar method of "dusting" the top of the shaft to create a very fine line on the top center of the shaft and locating off that, that also works.
                              Jim H.

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