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Re: CNC 4 inch focuser modification

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  • mrgrytt
    ... This is probably the biggest difficulty with the modification. The person owning the scope really needs to have the proper collimation tools and the
    Message 1 of 16 , Jan 31, 2006
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      --- In tmboptical@yahoogroups.com, "Danny Halstead"
      <dannyhalstead44@m...> wrote:
      >
      > Harvey,
      > Is there a place where someone who is not all that gifted
      > mechanically can send their scope for this modification with a
      > reasonable guarantee that afterwards the focuser will still be
      > centered with the objective and collimation of the objective still
      > right on?

      This is probably the biggest difficulty with the modification.
      The person owning the scope really needs to have the proper
      collimation tools and the ability to properly assemble the scope after
      the focuser modification.
      If, for whatever reason, you aren't able to do it yourself I
      could only suggest Thomas as the one who would definitely make it
      right for you. I have no idea if he would be interested in extra work
      at this time. He usually has his plate fairly full.

      > I have a silver CNC TMB 115 older scope with very little use and
      > have also had added the feather touch 2 inch focuser as well.
      > A general price estimate would be nice.

      After having the focuser for my TMB 175 modified I still have not
      been notified on the cost. I'm sure I'll find out soon.

      > I would love to have ThomasBack do the work but I am unsure if he
      > is interested or the best qualified since he is not the originator
      > of this modification but would however take his word if he would
      > be willing to do it it.

      Thomas would certainly be the most qualified person, without
      question. Whether he would be willing to do this is something only he
      can answer.
      The modification has no effect on the proper assembly and
      collimation of the scope. It only affects the precision of the
      rotation mechanism.

      > How about it. Is there any one out there
      > who can do this Any information would be most appreciated. The
      > original 3 inch focuser is still on the tube with the Feather Touch
      > acting only as a fine focus means.
      > R/S,
      > Danny Halstead

      In a few weeks I will be sending in the 3 inch focuser from my
      105/650 and perhaps the machine shop will be willing to do a few of
      them at once, as they did this time. Don't know for sure, but we
      could ask them about the amount they would be willing to do and the
      timing involved.

      Regards,
      Harvey
    • tmboptical
      ... after ... work ... not ... he ... Touch ... Hi Harvey, No, I can t possibly fit this into my work. I am backed up on not only current telescopes, design
      Message 2 of 16 , Feb 1, 2006
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        --- In tmboptical@yahoogroups.com, "mrgrytt" <mrgrytt@i...> wrote:
        >
        > --- In tmboptical@yahoogroups.com, "Danny Halstead"
        > <dannyhalstead44@m...> wrote:
        > >
        > > Harvey,
        > > Is there a place where someone who is not all that gifted
        > > mechanically can send their scope for this modification with a
        > > reasonable guarantee that afterwards the focuser will still be
        > > centered with the objective and collimation of the objective still
        > > right on?
        >
        > This is probably the biggest difficulty with the modification.
        > The person owning the scope really needs to have the proper
        > collimation tools and the ability to properly assemble the scope
        after
        > the focuser modification.
        > If, for whatever reason, you aren't able to do it yourself I
        > could only suggest Thomas as the one who would definitely make it
        > right for you. I have no idea if he would be interested in extra
        work
        > at this time. He usually has his plate fairly full.
        >
        > > I have a silver CNC TMB 115 older scope with very little use and
        > > have also had added the feather touch 2 inch focuser as well.
        > > A general price estimate would be nice.
        >
        > After having the focuser for my TMB 175 modified I still have
        not
        > been notified on the cost. I'm sure I'll find out soon.
        >
        > > I would love to have ThomasBack do the work but I am unsure if he
        > > is interested or the best qualified since he is not the originator
        > > of this modification but would however take his word if he would
        > > be willing to do it it.
        >
        > Thomas would certainly be the most qualified person, without
        > question. Whether he would be willing to do this is something only
        he
        > can answer.
        > The modification has no effect on the proper assembly and
        > collimation of the scope. It only affects the precision of the
        > rotation mechanism.
        >
        > > How about it. Is there any one out there
        > > who can do this Any information would be most appreciated. The
        > > original 3 inch focuser is still on the tube with the Feather
        Touch
        > > acting only as a fine focus means.
        > > R/S,
        > > Danny Halstead
        >
        > In a few weeks I will be sending in the 3 inch focuser from my
        > 105/650 and perhaps the machine shop will be willing to do a few of
        > them at once, as they did this time. Don't know for sure, but we
        > could ask them about the amount they would be willing to do and the
        > timing involved.
        >
        > Regards,
        > Harvey

        Hi Harvey,

        No, I can't possibly fit this into my work. I am backed up on not
        only current telescopes, design work, but also telescopes that
        need repair. Sorry I can't do this kind of work, but there are
        only 7 days in a week, and I work all of them.

        If customers want to modify their TMB telescopes, that is fine,
        but as any telescope company would tell you, modifying telescopes
        places them out of under warranty. This would not affect the lens,
        and other parts that were not modified, but I cannot foresee what
        can happen, when the telescope is modified in any way. It is not
        that I discourage modifying, it can take the telescope and make
        it better, but the owner must understand that they are now
        responsible for that modification.

        Thanks for understanding,

        Thomas Back
      • mrgrytt
        ... I certainly didn t think you would have time for something like this. Even though it s not very difficult for a person to do it themself it s a scary
        Message 3 of 16 , Feb 1, 2006
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          --- In tmboptical@yahoogroups.com, "tmboptical" <TMBoptical@a...> wrote:
          >
          > Hi Harvey,
          >
          > No, I can't possibly fit this into my work. I am backed up on not
          > only current telescopes, design work, but also telescopes that
          > need repair. Sorry I can't do this kind of work, but there are
          > only 7 days in a week, and I work all of them.

          I certainly didn't think you would have time for something like
          this.
          Even though it's not very difficult for a person to 'do it
          themself' it's a scary thing to recommend, particularly if they don't
          feel comfortable about it. I wouldn't want to see anyone take a
          chance of hurting their scope.

          > If customers want to modify their TMB telescopes, that is fine,
          > but as any telescope company would tell you, modifying telescopes
          > places them out of under warranty. This would not affect the lens,
          > and other parts that were not modified, but I cannot foresee what
          > can happen, when the telescope is modified in any way. It is not
          > that I discourage modifying, it can take the telescope and make
          > it better, but the owner must understand that they are now
          > responsible for that modification.
          >
          > Thanks for understanding,
          >
          > Thomas Back

          That's certainly very understandable. The good thing is that the
          scopes are fine without the modification. The modificaton only raises
          the level of perfection, but you can certainly get by without it.
          I would suspect that there could be some possible image shifting
          when loosening the collar on the Feathertouch 3.5 inch focuser too.
          The modification simply puts the CNC focuser a step ahead of most
          anything else in this area. Just makes a great focuser even greater.
          Also, I would be more than happy to help anyone with it if the
          location would make it reasonable. Maybe Tim would too.

          Regards,
          Harvey
        • Tube Tim
          ... Personally, I think this makes the classic CNC the best scope out there. ... If anyone in San Diego area is interested, contact me off list. Danny: If you
          Message 4 of 16 , Feb 1, 2006
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            >--- In tmboptical@yahoogroups.com, "mrgrytt" <mrgrytt@...> wrote:
            >
            > That's certainly very understandable. The good thing is that
            > the scopes are fine without the modification. The modificaton only
            > raises the level of perfection, but you can certainly get by
            > without it.
            > I would suspect that there could be some possible image
            > shifting when loosening the collar on the Feathertouch 3.5 inch
            > focuser too.
            > The modification simply puts the CNC focuser a step ahead of most
            > anything else in this area. Just makes a great focuser even
            > greater.

            Personally, I think this makes the classic CNC the best scope out there.


            > Also, I would be more than happy to help anyone with it if the
            > location would make it reasonable. Maybe Tim would too.

            If anyone in San Diego area is interested, contact me off list.

            Danny: If you want to send me the scope I can have this taken care of
            for you. Send me an email.

            ___
            Tim
          • Wayne G
            Hi Harvey, Date: Wed, 01 Feb 2006 12:51:58 -0000 From: mrgrytt Subject: Re: CNC 4 inch focuser modification Even though it s not very
            Message 5 of 16 , Feb 1, 2006
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              Hi Harvey,



              Date: Wed, 01 Feb 2006 12:51:58 -0000
              From: "mrgrytt" <mrgrytt@...>
              Subject: Re: CNC 4 inch focuser modification


              Even though it's not very difficult for a person to 'do it
              themself' it's a scary thing to recommend, particularly if they don't
              feel comfortable about it. I wouldn't want to see anyone take a
              chance of hurting their scope.


              [WG: ] I've been looking into doing this as well to my own 152 for a
              few years now, as sometimes my rotating section can go from turning very
              easy and smooth to being suddenly jammed up so tight that no effort at
              forward movement helps and I end up knocking the whole scope out of
              position and losing the object trying to get it loose again.

              I always intend to look into the matter 'later' but end up putting the
              scope away and forgetting about it until the next time I take it out!
              :^)

              Obviously, it would seem that the heart of the problem is that there is
              nothing other than the three set screws riding in the channel which both
              hold and guide the rotating sleeve in its motions.

              But I also hope/think it very likely that if I follow Thomas' adjustment
              procedures recently published (thanks Tom), this will probably either
              greatly ameliorate or even largely eliminate the problem to any
              reasonable extent, which I will try some day soon when I get the chance.
              But there is still the likelihood of the problem returning again later I
              fear. The key is in taking the weight off of the groove walls and
              eliminating the friction between them and the screws (which your
              modification accomplishes).

              However, as I do my own machining, I will be eventually settling on some
              solution of my own choosing--- I suspect there is more than one way to
              address the issue, and correct the deficiency so as to entirely
              eliminate it from coming back again and further improving the smoothness
              and stability of the rotating collar, which is imminently superb when it
              is working well.

              To be honest, my own ideas to this problem have been to take an entirely
              different approach to the one that you and Tim have chosen, but we
              shall see once I have the parts all apart in my hands what I will
              decide.

              In the meantime, as to your comments above, what I would ask and propose
              here is for maybe you, Tim, or some other enterprising and magnanimous
              person to put together a detailed description and drawings/photos of the
              disassembly, reassembly, and any other pertinent points, obstacles or
              hurdles for anyone undertaking such an improvement/modification of their
              focuser to follow, and maybe put it in the files section for all of us
              to refer to?

              I've looked at Tim's pictures of the parts, both privately as well as
              those recently published here, but they always leave me some questions
              as to what the issues were in taking it apart. Mechanically inclined as
              I am, I would feel better (as I think many would who are considering
              this) knowing exactly what they are getting into before taking a very
              expensive product like this apart. I think it is the time now for a
              detailed and thorough article on addressing this matter safely and with
              minimal risk, much like many others have published articles on taking
              apart corrector plates on SCTs and fixing loose primaries, mirror flop
              and focus shift. The fact that you say above that the procedure is not
              very difficult tells me that it is really quite simple once you see how
              the scope is put together, which obviously was designed to be very
              robust, as all TMB products have been!

              Can I compel you to be our volunteer to create such a document for us?
              :-) You wouldn't be recommending anything, just giving us the dry facts
              of what is involved and a roadmap based on your own knowledge and
              experience.

              Thanks,

              Wayne
            • mrgrytt
              ... Tim, You know I agree with that. Harvey
              Message 6 of 16 , Feb 1, 2006
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                --- In tmboptical@yahoogroups.com, "Tube Tim" <potentate@...> wrote:
                >
                > > The modification simply puts the CNC focuser a step ahead of most
                > > anything else in this area. Just makes a great focuser even
                > > greater.
                >
                > Personally, I think this makes the classic CNC the best scope out
                > there.
                > ___
                > Tim

                Tim,
                You know I agree with that.

                Harvey
              • Terry Tuggle
                Wayne, Tim sent me a PDF on disassembly for my Mod, I will post that in the files, and Thomas has asked me to combine his writ-up and my additional comments
                Message 7 of 16 , Feb 1, 2006
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                  Wayne,

                  Tim sent me a PDF on disassembly for my Mod, I will post that in the
                  files, and Thomas has asked me to combine his writ-up and my additional
                  comments into one procedure, which I will do after I receive and reassemble
                  my scope.



                  Terry



                  _____

                  From: tmboptical@yahoogroups.com [mailto:tmboptical@yahoogroups.com] On
                  Behalf Of Wayne G
                  Sent: Wednesday, February 01, 2006 3:48 PM
                  To: tmboptical@yahoogroups.com
                  Subject: [tmboptical] Re: CNC 4 inch focuser modification



                  Hi Harvey,



                  Date: Wed, 01 Feb 2006 12:51:58 -0000
                  From: "mrgrytt" <mrgrytt@...>
                  Subject: Re: CNC 4 inch focuser modification


                  Even though it's not very difficult for a person to 'do it
                  themself' it's a scary thing to recommend, particularly if they don't
                  feel comfortable about it. I wouldn't want to see anyone take a
                  chance of hurting their scope.


                  [WG: ] I've been looking into doing this as well to my own 152 for a
                  few years now, as sometimes my rotating section can go from turning very
                  easy and smooth to being suddenly jammed up so tight that no effort at
                  forward movement helps and I end up knocking the whole scope out of
                  position and losing the object trying to get it loose again.

                  I always intend to look into the matter 'later' but end up putting the
                  scope away and forgetting about it until the next time I take it out!
                  :^)

                  Obviously, it would seem that the heart of the problem is that there is
                  nothing other than the three set screws riding in the channel which both
                  hold and guide the rotating sleeve in its motions.

                  But I also hope/think it very likely that if I follow Thomas' adjustment
                  procedures recently published (thanks Tom), this will probably either
                  greatly ameliorate or even largely eliminate the problem to any
                  reasonable extent, which I will try some day soon when I get the chance.
                  But there is still the likelihood of the problem returning again later I
                  fear. The key is in taking the weight off of the groove walls and
                  eliminating the friction between them and the screws (which your
                  modification accomplishes).

                  However, as I do my own machining, I will be eventually settling on some
                  solution of my own choosing--- I suspect there is more than one way to
                  address the issue, and correct the deficiency so as to entirely
                  eliminate it from coming back again and further improving the smoothness
                  and stability of the rotating collar, which is imminently superb when it
                  is working well.

                  To be honest, my own ideas to this problem have been to take an entirely
                  different approach to the one that you and Tim have chosen, but we
                  shall see once I have the parts all apart in my hands what I will
                  decide.

                  In the meantime, as to your comments above, what I would ask and propose
                  here is for maybe you, Tim, or some other enterprising and magnanimous
                  person to put together a detailed description and drawings/photos of the
                  disassembly, reassembly, and any other pertinent points, obstacles or
                  hurdles for anyone undertaking such an improvement/modification of their
                  focuser to follow, and maybe put it in the files section for all of us
                  to refer to?

                  I've looked at Tim's pictures of the parts, both privately as well as
                  those recently published here, but they always leave me some questions
                  as to what the issues were in taking it apart. Mechanically inclined as
                  I am, I would feel better (as I think many would who are considering
                  this) knowing exactly what they are getting into before taking a very
                  expensive product like this apart. I think it is the time now for a
                  detailed and thorough article on addressing this matter safely and with
                  minimal risk, much like many others have published articles on taking
                  apart corrector plates on SCTs and fixing loose primaries, mirror flop
                  and focus shift. The fact that you say above that the procedure is not
                  very difficult tells me that it is really quite simple once you see how
                  the scope is put together, which obviously was designed to be very
                  robust, as all TMB products have been!

                  Can I compel you to be our volunteer to create such a document for us?
                  :-) You wouldn't be recommending anything, just giving us the dry facts
                  of what is involved and a roadmap based on your own knowledge and
                  experience.

                  Thanks,

                  Wayne










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                  [Non-text portions of this message have been removed]
                • Tube Tim
                  ... There you go Wayne. Note: Not I am not responsible for
                  Message 8 of 16 , Feb 1, 2006
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                    >--- In tmboptical@yahoogroups.com, "Wayne G" <fomalhaut@...> wrote:

                    <http://groups.yahoo.com/group/tmboptical/files/Disassembly_of_a_TMB_ClassicCNC_Telescope.pdf>

                    There you go Wayne. Note: Not I am not responsible for content nor
                    damage caused by someone attempting this. Please be sure you capable
                    of taking this on.


                    Tim

                    > In the meantime, as to your comments above, what I would ask and propose
                    > here is for maybe you, Tim, or some other enterprising and magnanimous
                    > person to put together a detailed description and drawings/photos of the
                    > disassembly, reassembly, and any other pertinent points, obstacles or
                    > hurdles for anyone undertaking such an improvement/modification of their
                    > focuser to follow, and maybe put it in the files section for all of us
                    > to refer to?
                  • Tube Tim
                    ... Terry, Our messages crossed so I deleted the redundant file as we both posted the PDF. Tim ...
                    Message 9 of 16 , Feb 1, 2006
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                      >--- In tmboptical@yahoogroups.com, "Terry Tuggle" <tlt284@...> wrote:
                      >

                      Terry,

                      Our messages crossed so I deleted the redundant file as we both posted
                      the PDF.


                      Tim

                      > Wayne,
                      >
                      > Tim sent me a PDF on disassembly for my Mod, I will post that in
                      > the files, and Thomas has asked me to combine his writ-up and my
                      > additional comments into one procedure, which I will do after I
                      > receive and reassemble my scope.
                      >
                      >
                      >
                      > Terry
                      >
                      >
                      >
                      > _____
                      >
                      > From: tmboptical@yahoogroups.com [mailto:tmboptical@yahoogroups.com] On
                      > Behalf Of Wayne G
                      > Sent: Wednesday, February 01, 2006 3:48 PM
                      > To: tmboptical@yahoogroups.com
                      > Subject: [tmboptical] Re: CNC 4 inch focuser modification
                      >
                      >
                      >
                      > Hi Harvey,
                      >
                      >
                      >
                      > Date: Wed, 01 Feb 2006 12:51:58 -0000
                      > From: "mrgrytt" <mrgrytt@...>
                      > Subject: Re: CNC 4 inch focuser modification
                      >
                      >
                      > Even though it's not very difficult for a person to 'do it
                      > themself' it's a scary thing to recommend, particularly if they don't
                      > feel comfortable about it. I wouldn't want to see anyone take a
                      > chance of hurting their scope.
                      >
                      >
                      > [WG: ] I've been looking into doing this as well to my own 152 for a
                      > few years now, as sometimes my rotating section can go from turning very
                      > easy and smooth to being suddenly jammed up so tight that no effort at
                      > forward movement helps and I end up knocking the whole scope out of
                      > position and losing the object trying to get it loose again.
                      >
                      > I always intend to look into the matter 'later' but end up putting the
                      > scope away and forgetting about it until the next time I take it out!
                      > :^)
                      >
                      > Obviously, it would seem that the heart of the problem is that there is
                      > nothing other than the three set screws riding in the channel which both
                      > hold and guide the rotating sleeve in its motions.
                      >
                      > But I also hope/think it very likely that if I follow Thomas' adjustment
                      > procedures recently published (thanks Tom), this will probably either
                      > greatly ameliorate or even largely eliminate the problem to any
                      > reasonable extent, which I will try some day soon when I get the chance.
                      > But there is still the likelihood of the problem returning again later I
                      > fear. The key is in taking the weight off of the groove walls and
                      > eliminating the friction between them and the screws (which your
                      > modification accomplishes).
                      >
                      > However, as I do my own machining, I will be eventually settling on some
                      > solution of my own choosing--- I suspect there is more than one way to
                      > address the issue, and correct the deficiency so as to entirely
                      > eliminate it from coming back again and further improving the smoothness
                      > and stability of the rotating collar, which is imminently superb when it
                      > is working well.
                      >
                      > To be honest, my own ideas to this problem have been to take an entirely
                      > different approach to the one that you and Tim have chosen, but we
                      > shall see once I have the parts all apart in my hands what I will
                      > decide.
                      >
                      > In the meantime, as to your comments above, what I would ask and propose
                      > here is for maybe you, Tim, or some other enterprising and magnanimous
                      > person to put together a detailed description and drawings/photos of the
                      > disassembly, reassembly, and any other pertinent points, obstacles or
                      > hurdles for anyone undertaking such an improvement/modification of their
                      > focuser to follow, and maybe put it in the files section for all of us
                      > to refer to?
                      >
                      > I've looked at Tim's pictures of the parts, both privately as well as
                      > those recently published here, but they always leave me some questions
                      > as to what the issues were in taking it apart. Mechanically inclined as
                      > I am, I would feel better (as I think many would who are considering
                      > this) knowing exactly what they are getting into before taking a very
                      > expensive product like this apart. I think it is the time now for a
                      > detailed and thorough article on addressing this matter safely and with
                      > minimal risk, much like many others have published articles on taking
                      > apart corrector plates on SCTs and fixing loose primaries, mirror flop
                      > and focus shift. The fact that you say above that the procedure is not
                      > very difficult tells me that it is really quite simple once you see how
                      > the scope is put together, which obviously was designed to be very
                      > robust, as all TMB products have been!
                      >
                      > Can I compel you to be our volunteer to create such a document for us?
                      > :-) You wouldn't be recommending anything, just giving us the dry facts
                      > of what is involved and a roadmap based on your own knowledge and
                      > experience.
                      >
                      > Thanks,
                      >
                      > Wayne
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      >
                      > SPONSORED LINKS
                      >
                      >
                      > Tmb
                      >
                      <http://groups.yahoo.com/gads?t=ms&k=Tmb&w1=Tmb&w2=Astronomy+magazine&w3=Ast
                      > ronomy&c=3&s=48&.sig=S-9fdBRdYoZMidF3CQ4kxA>
                      >
                      > Astronomy
                      >
                      <http://groups.yahoo.com/gads?t=ms&k=Astronomy+magazine&w1=Tmb&w2=Astronomy+
                      > magazine&w3=Astronomy&c=3&s=48&.sig=futZRZpaAgNPqk1ni_L7jQ> magazine
                      >
                      > Astronomy
                      >
                      <http://groups.yahoo.com/gads?t=ms&k=Astronomy&w1=Tmb&w2=Astronomy+magazine&
                      > w3=Astronomy&c=3&s=48&.sig=CfIkLxvgk7f1_Znsss7-cg>
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                      >
                      >
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                      >
                      >
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                      >
                      >
                      > [Non-text portions of this message have been removed]
                      >
                    • Tube Tim
                      ... Hi Wayne, Not Harvey, but Tim here, ... I ve been thinking thru the rotating focuser for years myself. Without the fix, mine always spun smoothly, you just
                      Message 10 of 16 , Feb 1, 2006
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                        >--- In tmboptical@yahoogroups.com, "Wayne G" <fomalhaut@...> wrote:
                        >
                        > Hi Harvey,

                        Hi Wayne,

                        Not Harvey, but Tim here,


                        >
                        > [WG: ] I've been looking into doing this as well to my own 152
                        > for a few years now, as sometimes my rotating section can go from
                        > turning very easy and smooth to being suddenly jammed up so tight
                        > that no effort at forward movement helps and I end up knocking the
                        > whole scope out of position and losing the object trying to get it
                        > loose again.

                        I've been thinking thru the rotating focuser for years myself.
                        Without the fix, mine always spun smoothly, you just have to keep
                        upward pressure on the drawtube housing.

                        >
                        > I always intend to look into the matter 'later' but end up putting
                        > the scope away and forgetting about it until the next time I
                        > take it out!
                        > :^)
                        >
                        > Obviously, it would seem that the heart of the problem is that there
                        > is nothing other than the three set screws riding in the channel
                        > which both hold and guide the rotating sleeve in its motions.
                        >

                        This is true as far as holding the sleeve from falling back. The
                        sleeve and it's contact with the main flange are very well machined
                        and precisely fit.

                        > But I also hope/think it very likely that if I follow Thomas'
                        > adjustment procedures recently published (thanks Tom), this will
                        > probably either greatly ameliorate or even largely eliminate the
                        > problem to any reasonable extent, which I will try some day soon
                        > when I get the chance.

                        TMB's adjustment is for the drawtube friction / centering, no bearing
                        on the rotating part.

                        > But there is still the likelihood of the problem returning again
                        > later I fear. The key is in taking the weight off of the groove
                        > walls and eliminating the friction between them and the screws
                        > (which your modification accomplishes).

                        Correct, you have to hold the sleeve up into the housing so the
                        setscrews never contact metal groove.

                        >
                        > However, as I do my own machining, I will be eventually settling on
                        > some solution of my own choosing--- I suspect there is more than
                        > one way to address the issue, and correct the deficiency so as to
                        > entirely eliminate it from coming back again and further improving
                        > the smoothness and stability of the rotating collar, which is
                        > imminently superb when it is working well.
                        >

                        Agreed the collar is super smooth. The fix makes the mechanism behave
                        like this at all times without the need to hold the focuser from
                        slipping onto the set screws. Imagine, loosen the lock screw, gently
                        rotate to exact position, even with heavy load on focuser, then gently
                        lock it down. A lot of force is not required.

                        > To be honest, my own ideas to this problem have been to take an
                        > entirely different approach to the one that you and Tim have chosen,
                        > but we shall see once I have the parts all apart in my hands what I
                        > will decide.
                        >

                        I really wish you could come up with something that didn't require any
                        machining. I've looked at this and it seems every thing requires some
                        machining.

                        > In the meantime, as to your comments above, what I would ask and
                        > propose here is for maybe you, Tim, or some other enterprising and
                        > magnanimous person to put together a detailed description and
                        > drawings/photos of the disassembly, reassembly, and any other
                        > pertinent points, obstacles or hurdles for anyone undertaking such
                        > an improvement/modification of their focuser to follow, and maybe
                        > put it in the files section for all of us to refer to?
                        >

                        I got the disassembly part done and posted. My one comment about
                        reassembly would be to prevent stripping out the focuser housing when
                        put the long threaded rods back into place. To start the thread
                        easier, turn the rod CCW until you feel a 'click' of the threads
                        lining up (in phase) and then start turning CW.

                        > I've looked at Tim's pictures of the parts, both privately as well
                        > as those recently published here, but they always leave me some
                        > questions as to what the issues were in taking it apart.
                        > Mechanically inclined as I am, I would feel better (as I think many
                        > would who are considering this) knowing exactly what they are
                        > getting into before taking a very expensive product like this apart.
                        > I think it is the time now for a detailed and thorough article on
                        > addressing this matter safely and with minimal risk, much like many
                        > others have published articles on taking apart corrector plates on
                        > SCTs and fixing loose primaries, mirror flop and focus shift. The
                        > fact that you say above that the procedure is not very difficult
                        > tells me that it is really quite simple once you see how the scope
                        > is put together, which obviously was designed to be very
                        > robust, as all TMB products have been!
                        >

                        It's not to bad to take apart as long as one marks the orientation of
                        everything. In fact if you don't touch the push screws on the lens
                        cell it goes back to near perfect collimation. Shoot on my 229, I
                        didn't mark the tube as to orientation of alignment with lens etc and
                        it still came out real close. The tubes are obviously cut square, a
                        huge help.

                        > Can I compel you to be our volunteer to create such a document for
                        > us? :-)
                        > You wouldn't be recommending anything, just giving us the dry facts
                        > of what is involved and a roadmap based on your own knowledge and
                        > experience.

                        Let me know what you guys / gals think of the paper. I can add to it
                        if need be. I could even tear down my 152 again and take better pics.

                        ___
                        Tim
                      • mrgrytt
                        Hi Wayne, ... I remember our discussions about this issue some time ago. Perhaps you ll be able to come up with an even easier method of correcting the
                        Message 11 of 16 , Feb 1, 2006
                        • 0 Attachment
                          Hi Wayne,

                          --- In tmboptical@yahoogroups.com, "Wayne G" <fomalhaut@...> wrote:
                          >
                          > [WG: ] I've been looking into doing this as well to my own 152
                          > for a few years now, as sometimes my rotating section can go from
                          > turning very easy and smooth to being suddenly jammed up so tight
                          > that no effort at forward movement helps and I end up knocking the
                          > whole scope out of position and losing the object trying to get it
                          > loose again.
                          >
                          > I always intend to look into the matter 'later' but end up putting
                          > the scope away and forgetting about it until the next time I take it
                          > out! :^)

                          I remember our discussions about this issue some time ago.
                          Perhaps you'll be able to come up with an even easier method of
                          correcting the problem. If you do, it will be good news for everyone
                          who owns one of the original TMB optical tubes.
                          It was actually pretty easy to see what was needed to do the job.
                          The hard part was figuring out how to do it without loosing any
                          outward drawtube travel. That was accomplished, but it made the "fix"
                          a bit more sophistocated than originally thought.
                          Be sure and let us know what you come up with if you find an
                          additional way to correct it. Also, be sure and get the full details
                          on the existing "fix". If you do your own machining you could
                          probably handle it very easily, should you decide to do it that way.
                          With the present modification I honestly think you could rotate
                          the focuser at 500 RPM overnight with 10 pounds on it while aimed at
                          the Zenith and it would still be perfect in the morning. It is worth
                          looking at before you do something else.

                          Regards,
                          Harvey
                        • dennis
                          Why would anyone want to deconstruct an already great focuser, anyway??? ... From: Tube Tim To: tmboptical@yahoogroups.com Sent: Wednesday, February 01, 2006
                          Message 12 of 16 , Feb 1, 2006
                          • 0 Attachment
                            Why would anyone want to deconstruct an already great focuser, anyway???
                            ----- Original Message -----
                            From: Tube Tim
                            To: tmboptical@yahoogroups.com
                            Sent: Wednesday, February 01, 2006 9:01 PM
                            Subject: [tmboptical] Re: CNC 4 inch focuser modification


                            >--- In tmboptical@yahoogroups.com, "Wayne G" <fomalhaut@...> wrote:


                            <http://groups.yahoo.com/group/tmboptical/files/Disassembly_of_a_TMB_Classic
                            CNC_Telescope.pdf>

                            There you go Wayne. Note: Not I am not responsible for content nor
                            damage caused by someone attempting this. Please be sure you capable
                            of taking this on.


                            Tim

                            > In the meantime, as to your comments above, what I would ask and propose
                            > here is for maybe you, Tim, or some other enterprising and magnanimous
                            > person to put together a detailed description and drawings/photos of the
                            > disassembly, reassembly, and any other pertinent points, obstacles or
                            > hurdles for anyone undertaking such an improvement/modification of their
                            > focuser to follow, and maybe put it in the files section for all of us
                            > to refer to?







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                          • mrgrytt
                            ... Dennis, I think in the most strict sense of the word it really isn t the focuser that is being modified, but rather the way in which it is connected to
                            Message 13 of 16 , Feb 2, 2006
                            • 0 Attachment
                              --- In tmboptical@yahoogroups.com, "dennis" <tracy_tracy@...> wrote:
                              >
                              > Why would anyone want to deconstruct an already great focuser,
                              > anyway???

                              Dennis,
                              I think in the most strict sense of the word it really isn't the
                              "focuser" that is being modified, but rather the way in which it is
                              connected to the rear tube flange.
                              We want to be able to rotate it as precisely as we can focus with
                              it. Although it is very good already, with the modification it can be
                              made better than anything else on the market in the rotating function.

                              Harvey
                            • dennis
                              Must have read it wrong at first, sorry... ... From: mrgrytt To: tmboptical@yahoogroups.com Sent: Thursday, February 02, 2006 10:27 AM Subject: [tmboptical]
                              Message 14 of 16 , Feb 2, 2006
                              • 0 Attachment
                                Must have read it wrong at first, sorry...
                                ----- Original Message -----
                                From: mrgrytt
                                To: tmboptical@yahoogroups.com
                                Sent: Thursday, February 02, 2006 10:27 AM
                                Subject: [tmboptical] Re: CNC 4 inch focuser modification


                                --- In tmboptical@yahoogroups.com, "dennis" <tracy_tracy@...> wrote:
                                >
                                > Why would anyone want to deconstruct an already great focuser,
                                > anyway???

                                Dennis,
                                I think in the most strict sense of the word it really isn't the
                                "focuser" that is being modified, but rather the way in which it is
                                connected to the rear tube flange.
                                We want to be able to rotate it as precisely as we can focus with
                                it. Although it is very good already, with the modification it can be
                                made better than anything else on the market in the rotating function.

                                Harvey







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