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  • #16
    Hey there AXKIKER

    Did you try any of the suggestions that I advised you? One thing that I failed to mention is that one of your problems may be from you using too small of a machine. Almost all of the "home shop guys" all have smaller sized equipment and a small machine simply doesn't have the necessary rigidity that a larger machine has. Getting rid of your chatter problem may be impossible because of this "lack of rigidity issue". I have always said that it has been my experience that """it is a lot easier to make a large machine smaller, than it is to make a small machine big""" If you could get rid of the chatter marks that you have now, that is on the work piece now, then try using my before-mentioned fixes.

    Also,,, You keep saying that you are still using HSS for your cutter. I would recommend that you use carbide, with as small as possible radius on the cutting edge, and with positive back rake on the top of the cutter. Then try the upside down, in reverse trick,,, then use the 2X4 trick also.

    Your friend, Doggie
    Last edited by Doggie; 02-09-2015, 12:34 PM. Reason: Cause I could???

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    • #17
      Originally posted by Doggie View Post
      Hey there AXKIKER

      Did you try any of the suggestions that I advised you? One thing that I failed to mention is that one of your problems may be from you using too small of a machine. Almost all of the "home shop guys" all have smaller sized equipment and a small machine simply doesn't have the necessary rigidity that a larger machine has. Getting rid of your chatter problem may be impossible because of this "lack of rigidity issue". I have always said that it has been my experience that """it is a lot easier to make a large machine smaller, than it is to make a small machine big""" If you could get rid of the chatter marks that you have now, that is on the work piece now, then try using my before-mentioned fixes.

      Also,,, You keep saying that you are still using HSS for your cutter. I would recommend that you use carbide, with as small as possible radius on the cutting edge, and with positive back rake on the top of the cutter. Then try the upside down, in reverse trick,,, then use the 2X4 trick also.

      Your friend, Doggie
      Yes I have tried a few things.

      So far really slowing it down to roughly 60 - 100 rpm and increasing the feed rate has helped take 75-85% of the chatter out. It now only comes and goes infrequently. I have not tried in reverse as my lathe currently doesnt have reverse switch. I could swap a few wires but I just havent had time yet.

      I did find that I think a couple of the adapters I was using may have worn slightly allowing some slight play. Im going to make a couple more out of a harder stock as soon as I can get to the metal shop.

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      • #18
        If you are unable to completely stop the chatter but still able to manage it so it isn't too deep, perhaps you could make a few finishing passes with a shear tool and .001" depth of cut to clean things up. I realize it isn't a solution for the chatter but it would be a method of attaining a good outcome.
        If you aren't familiar with a shear tool there are several threads on HSM about them. Here is an outside link: http://www.gadgetbuilder.com/VerticalShearBit.html

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        • #19
          Originally posted by firbikrhd1 View Post
          If you are unable to completely stop the chatter but still able to manage it so it isn't too deep, perhaps you could make a few finishing passes with a shear tool and .001" depth of cut to clean things up. I realize it isn't a solution for the chatter but it would be a method of attaining a good outcome.
          If you aren't familiar with a shear tool there are several threads on HSM about them. Here is an outside link: http://www.gadgetbuilder.com/VerticalShearBit.html
          Yup.... you read my mind.. That is exactly what I was thinking about doing.

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          • #20
            I've been following this thread with some interest, there IS a way to use a steady while cutting long tapers, but it's complicated, a bit of a compromise and needs a taper attachment on the lathe...

            First rough the desired taper, chatter can be allowed up until your finish cuts, or you may be able to use this method in the roughing passes with a little care and some calculations to get the tailstock offset...

            Set the taper attachment to double the required taper (so the included angle, not half)

            Set the work between centres (with a dog driving from a faceplate or against one of the chuck jaws) and set tailstock over in the WRONG direction so that the back side of the tapered piece is (or will be) parallel with the lathe axis (so if your taper is smaller at the tailstock end, the tailstock moves away from you) and indicate it in so you get a minimal deviation over the length of the work *on the back side* or for initial passes so that the deviation is equal to your desired taper/ft

            Set your travelling steady (follow rest) against the back of the work - the top finger will need to be clear to allow for the diameter change along the work, so it's not an ideal support but it will help reduce chatter

            Start your finish (or roughing) cuts! The travelling steady's horizontal finger can be adjusted into contact with freshly-cut taper once you move away from the tailstock centre, and if all's set right will follow the newly-cut taper on the back of the work.

            It's an unusual way to do it, but it has worked for me on long skinny tapers...
            Rules are for the obedience of fools, and the guidance of wise men.

            Holbrook Model C Number 13 lathe, Testa 2U universal mill, bikes and tools

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            • #21
              Speaking of chatter, yesterday when I was making a distributor hole plug for a 460 Ford I was cutting an O-ring groove and using the old lantern style tool holder since the cutoff tool was almost exactly the right size for the groove and it needed to be only .080 deep. It chattered badly when it really shouldn't have. For some reason I decided to switch to an independent four jaw chuck from a three jaw scroll chuck. Both chucks are similar in weight but the chatter was reduced to almost nothing. I was turning a short piece of 1 3/4" shaft for the plug and had 4 inches sticking out of the chuck but I didn't want to waste any of the shaft by cutting it to a shorter more appropriate length. Besides, if I was turning on a piece that had to be that length I wouldn't be able to cut it shorter anyways.

              I can only surmise that the four jaw chuck was holding the workpiece more securely than the three jaw and eliminated a minuscule amount of movement which caused most of the chatter. This movement I believe was either between the shaft and jaws or between the jaws and T-slots in the chuck itself. Every revolution of the chuck would allow the force of the tool tip to push the shaft away so very slightly loading one jaw enough to eliminate the minuscule clearance and then when the jaw rotated 180 degrees the clearance would be opened up fully again. It would do this three times per chuck revolution.

              Just a hypothesis of course, I may be totally out to lunch on the cause but as far as chatter goes, who knew that the chuck itself could enter into it?
              Location: Saskatoon, Saskatchewan, Canada

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              • #22
                The other thing in dealing with chatter is that existing chatter marks on the work will induce more chatter by giving feedback at the resonant frequency. If there are existing chatter marks you might have to turn at an extremely slow sfm to cut through the chatter marks without resonance. Then you can get back to normal cutting.

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