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  • Trials and tribulations

    I recently completed my set of ER40 collets so I now have a full set for the mill so after seeing Bob's thread on the ER collet chuck he made for his lathe I thought I might go ahead and give it a go...

    I had a piece of 2" steel 6 1/2" long handy so I drilled a 1" hole up the middle of it then worked on getting the taper right for the headstock..It is 5MT...

    I chucked up a 5MT reducing in the lathe and proceeded to adjust the topslide to the correct angle with the help of a dial indicator....Upon turning the part up it was a disaster as it was obviously set for the wrong angle and one end was too small...

    OK Take 2...Another piece of steel 6 1/2 inches long with a 25.4mm hole through the middle.. This time I decided to use the taper turning attachment on the lathe...It was not fitted to the lathe and I never had much success using it, that was the reason I was using the top slide...

    OK now before we go any further there is an adult content warning attached to the next paragraph..If you do not like reading about blatant abuse of tools then please skip ahead one paragraph...

    When I got the taper turning attachment I was extremely green, it was pre internet days for me and the only knowledge I has was from books..And I knew no one else who had a lathe...So the taper turning attachment slides had tight spots in them..So I knew that you lap valves into engine heads with lapping compound so I got some valve lapping compound and proceeded to "lap" the taper turning slides together...Yes I know it was a stupid thing to do but at that time I didn't know any better...So the slides on the taper turning attachment are a bit worn and it still does not slide "smoothly" together..

    I pulled the taper turning attachment out and proceeded to pull it apart to check for damage and clean it up...Then I discovered both gib's are banana shaped by quite a bit...So looks like I have to flatten them a bit...be nice to have a surface grinder about now...Maybe next year...

    So looks like I now have to rebuild the taper turning attachment first with my new amateur scraping skills then I might be able to continue on with the ER collet holder... Nothing is ever easy is it...

    I would have more pics but the batteries went flat on the camera while in the middle of picture taking..

    The nice shiny piece of scrap



    One of the taper turning slides with the wear marks wear I "lapped" it in..

    Precision takes time.

  • #2
    I'm smack dab in the middle of building my taper attachment for my SB9. I'm hoping that the attachment doesn't need to be that flat for it to work? I suspect you may have other problems.

    Keep in mind it's vital to keep the tool bit perfectly centered the full length of the cut or the taper won't come out as you plan. If the bit crosses the centerline axis you will dig in deeper then you want because the bit is closer to the centerline axis at the point where it crosses over.
    Last edited by Your Old Dog; 03-29-2009, 07:13 AM.
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    • #3
      I don't know about flat but the slides will need to be smooth as silk so the taper gets turned perfectly...To my way of thinking if the slide has any tight spots in it when you are turning your taper and it hits one of the tight spots this will cause the carriage to slow down a tiny amount and thus the tool will cut just that bit deeper for that area..
      Precision takes time.

      Comment


      • #4
        Ringer,
        You got a Chinese boring head ?



        .
        .

        Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



        Comment


        • #5
          wow now that is a bit different..Yes I do have a boring head and I do have a 3MT arbour for it so it can fit in the tailstock...

          I see you also have a taper turning attachment fitted to your lathe, covered in chips much like mine was before I took it off..
          Precision takes time.

          Comment


          • #6
            You make a stub to fit the boring head with a centre drilled hole in it and fit it.
            You then make a second one but leave it in the chuck and don't remove it, this guarantees concentricity, even if your chuck is suspect.
            The work is put between these female 'centres' using a ball bearing inbetween at both ends. This allows the work to revolve off the centre plane without cocking on the centres.

            The work is driven via a driving dog of some description. Adjustment is made by using the slide of the boring head.

            Yes this lathe does have a taper turning attachment but to be honest it's a pain to use compared to the boring head method.
            And before anyone asks about the play in the tailstock barrel affecting the angle, well fix the damn play, that's what you have a lathe for.

            .
            .

            Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



            Comment


            • #7
              Originally posted by Ringer
              I recently completed my set of ER40 collets so I now have a full set for the mill so after seeing Bob's thread on the ER collet chuck he made for his lathe I thought I might go ahead and give it a go...

              I had a piece of 2" steel 6 1/2" long handy so I drilled a 1" hole up the middle of it then worked on getting the taper right for the headstock..It is 5MT...

              I chucked up a 5MT reducing in the lathe and proceeded to adjust the topslide to the correct angle with the help of a dial indicator....Upon turning the part up it was a disaster as it was obviously set for the wrong angle and one end was too small...

              OK Take 2...Another piece of steel 6 1/2 inches long with a 25.4mm hole through the middle.. This time I decided to use the taper turning attachment on the lathe...It was not fitted to the lathe and I never had much success using it, that was the reason I was using the top slide...

              OK now before we go any further there is an adult content warning attached to the next paragraph..If you do not like reading about blatant abuse of tools then please skip ahead one paragraph...

              When I got the taper turning attachment I was extremely green, it was pre internet days for me and the only knowledge I has was from books..And I knew no one else who had a lathe...So the taper turning attachment slides had tight spots in them..So I knew that you lap valves into engine heads with lapping compound so I got some valve lapping compound and proceeded to "lap" the taper turning slides together...Yes I know it was a stupid thing to do but at that time I didn't know any better...So the slides on the taper turning attachment are a bit worn and it still does not slide "smoothly" together..

              I pulled the taper turning attachment out and proceeded to pull it apart to check for damage and clean it up...Then I discovered both gib's are banana shaped by quite a bit...So looks like I have to flatten them a bit...be nice to have a surface grinder about now...Maybe next year...

              So looks like I now have to rebuild the taper turning attachment first with my new amateur scraping skills then I might be able to continue on with the ER collet holder... Nothing is ever easy is it...

              I would have more pics but the batteries went flat on the camera while in the middle of picture taking..

              The nice shiny piece of scrap



              One of the taper turning slides with the wear marks wear I "lapped" it in..

              Any machinist would just measure it and call it a taper no go guage. LOL

              hey it looks nice..

              Comment


              • #8
                Ringer,

                Would it not be possible to cut the taper between centers using the top slide as in your first try, but before drilling the through hole? This would allow you to remove the new taper before it reached final size, blue it, and check it in the headstock taper to ensure that the angle is correct, then replace it between centers, where it should still run true. Any minor angular adjustments to the top slide can then be made and the taper checked again before reaching finished size, when it can be mounted direct into the headstock spindle and the center hole drilled in place.

                By the way, ball ended tappet adjusting screws from older small OHV engines make nice hardened ball centers for the boring head if using John Stevenson's setup in the photo above.

                franco
                Last edited by franco; 03-29-2009, 10:26 PM.

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