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    An "hardware" advice for linear rails

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    • achrnundefined
      achrn @A Former User
      last edited by

      @thedragonlord said in An "hardware" advice for linear rails:

      so in your opinion the second rail is almost unuseful in my configuration if I understood well, right?

      I don't think it's an easy yes / no.

      I don't think it's necesary.
      It will have some minor benefits, but I don't think they are large (if your rails are reasonable ones).
      If you can make the gantry run smoothly (i.e. no binding or stiffening of the carriages) it won't do any harm.

      Personally, I'd use a larger section (2040 or a hollow box) as the gantry rather than double up the rails. For a 500mm span gantry I would probably go larger than 2020, but I haven't built a printer with a traveling gantry so I'm going by theory not practical experience.

      deckingmanundefined A Former User? 2 Replies Last reply Reply Quote 0
      • deckingmanundefined
        deckingman @achrn
        last edited by

        @achrn said in An "hardware" advice for linear rails:

        Personally, I'd use a larger section (2040 or a hollow box) as the gantry rather than double up the rails. For a 500mm span gantry I would probably go larger than 2020, but I haven't built a printer with a traveling gantry so I'm going by theory not practical experience.

        Interesting. When you criticised my post about the value of using maths to calculate beam deflection, you said quote" ....... I remain of the opinion that my estimate of 0.03mm is closer to reality......." So you think that 0.03mm beam deflection is unacceptable despite never having build a printer a printer with a travelling gantry. If you consider 0.03mm deflection to be unacceptable, what would you consider to be acceptable? Just curious.

        Ian
        https://somei3deas.wordpress.com/
        https://www.youtube.com/@deckingman

        1 Reply Last reply Reply Quote 0
        • A Former User?
          A Former User @achrn
          last edited by A Former User

          @achrn said in An "hardware" advice for linear rails:

          @thedragonlord said in An "hardware" advice for linear rails:

          so in your opinion the second rail is almost unuseful in my configuration if I understood well, right?

          I don't think it's an easy yes / no.

          I don't think it's necesary.
          It will have some minor benefits, but I don't think they are large (if your rails are reasonable ones).
          If you can make the gantry run smoothly (i.e. no binding or stiffening of the carriages) it won't do any harm.

          Personally, I'd use a larger section (2040 or a hollow box) as the gantry rather than double up the rails. For a 500mm span gantry I would probably go larger than 2020, but I haven't built a printer with a traveling gantry so I'm going by theory not practical experience.

          Thanks again! Just a last question....what's a hollow box?

          achrnundefined 1 Reply Last reply Reply Quote 0
          • Yveskeundefined
            Yveske
            last edited by

            @TheDragonLord Would it be an option to add a rail in front of the motors ?

            5d0cdcd3-1275-44b2-8ad0-d56b00a411b9-image.png

            A Former User? 1 Reply Last reply Reply Quote 0
            • A Former User?
              A Former User @Yveske
              last edited by

              @yveske said in An "hardware" advice for linear rails:

              @TheDragonLord Would it be an option to add a rail in front of the motors ?

              5d0cdcd3-1275-44b2-8ad0-d56b00a411b9-image.png

              no, absolutely

              fcwiltundefined 1 Reply Last reply Reply Quote 0
              • fcwiltundefined
                fcwilt @A Former User
                last edited by

                @thedragonlord

                Hi,

                Could you send me a STEP file of the gray parts holding the pulleys?

                There is a arrangement I want to try out and post here for you to look at.

                Frederick

                Printers: a E3D MS/TC setup and a RatRig Hybrid. Using Duet 3 hardware running 3.4.6

                A Former User? 1 Reply Last reply Reply Quote 0
                • A Former User?
                  A Former User
                  last edited by

                  @fcwilt said in An "hardware" advice for linear rails:

                  @thedragonlord

                  Hi,

                  Could you send me a STEP file of the gray parts holding the pulleys?

                  There is a arrangement I want to try out and post here for you to look at.

                  Frederick

                  If you mean the flanges wich connect the X gantry to the Y linear rails I can't send the file because they're part I bought and the sellers sended me the STLs only for reference with the promise to not share them

                  fcwiltundefined 1 Reply Last reply Reply Quote 0
                  • fcwiltundefined
                    fcwilt @A Former User
                    last edited by

                    @thedragonlord said in An "hardware" advice for linear rails:

                    If you mean the flanges wich connect the X gantry to the Y linear rails I can't send the file because they're part I bought and the sellers sended me the STLs only for reference with the promise to not share them.

                    Understood.

                    How many of what we see in the images are parts you bought?

                    Frederick

                    Printers: a E3D MS/TC setup and a RatRig Hybrid. Using Duet 3 hardware running 3.4.6

                    A Former User? 1 Reply Last reply Reply Quote 0
                    • A Former User?
                      A Former User @fcwilt
                      last edited by

                      @fcwilt said in An "hardware" advice for linear rails:

                      @thedragonlord said in An "hardware" advice for linear rails:

                      If you mean the flanges wich connect the X gantry to the Y linear rails I can't send the file because they're part I bought and the sellers sended me the STLs only for reference with the promise to not share them.

                      Understood.

                      How many of what we see in the images are parts you bought?

                      Frederick

                      just the two flanges and the vertical plate wich connects to the rail cursor

                      fcwiltundefined 1 Reply Last reply Reply Quote 1
                      • fcwiltundefined
                        fcwilt @A Former User
                        last edited by

                        @thedragonlord said in An "hardware" advice for linear rails:

                        just the two flanges and the vertical plate which connects to the rail cursor

                        It would be the part I wanted to modify. That seems to be the way of the universe. 😁

                        Were they designed for you or were they part of another printer design?

                        Thanks.

                        Frederick

                        Printers: a E3D MS/TC setup and a RatRig Hybrid. Using Duet 3 hardware running 3.4.6

                        A Former User? 1 Reply Last reply Reply Quote 0
                        • A Former User?
                          A Former User @fcwilt
                          last edited by

                          @fcwilt said in An "hardware" advice for linear rails:

                          @thedragonlord said in An "hardware" advice for linear rails:

                          just the two flanges and the vertical plate which connects to the rail cursor

                          It would be the part I wanted to modify. That seems to be the way of the universe. 😁

                          Were they designed for you or were they part of another printer design?

                          Thanks.

                          Frederick

                          it's a kit for the Tronxy X5S

                          fcwiltundefined 1 Reply Last reply Reply Quote 0
                          • fcwiltundefined
                            fcwilt @A Former User
                            last edited by

                            @thedragonlord said in An "hardware" advice for linear rails:

                            it's a kit for the Tronxy X5S

                            Thanks much. Maybe they have a doc showing the dimensions - I could work from that.

                            Frederick

                            Printers: a E3D MS/TC setup and a RatRig Hybrid. Using Duet 3 hardware running 3.4.6

                            A Former User? 1 Reply Last reply Reply Quote 0
                            • A Former User?
                              A Former User @fcwilt
                              last edited by A Former User

                              @fcwilt said in An "hardware" advice for linear rails:

                              @thedragonlord said in An "hardware" advice for linear rails:

                              it's a kit for the Tronxy X5S

                              Thanks much. Maybe they have a doc showing the dimensions - I could work from that.

                              Frederick

                              the seller is DMaker. com

                              EDIT
                              dmaker.it not .com and the kit is named KIT V2 ECO

                              1 Reply Last reply Reply Quote 1
                              • achrnundefined
                                achrn @A Former User
                                last edited by

                                @thedragonlord said in An "hardware" advice for linear rails:

                                Thanks again! Just a last question....what's a hollow box?

                                I mean a rectangular tubular member.

                                This is returning to a comment made up the thread - 2020 pultrusion (and similar) is good in lots of ways, but it's not the best from either a sructural strength or stiffness point of view.

                                In general terms, for resting bending you want material spaced away from the centre of the section - so for bending in one direction only you end up with 'I' beams that have chunky flanges and tall narrow webs that are mainly just there to hold the flanges apart but acting together. If you have similar bending forces in both directions you want flanges in both directions, so you end up with a rectangular tube, or box.

                                The other big win for tubes / boxes is that closed hollow sections are much much better than 'open' sections in torsion. So of these two sections, if they had same quantity of material and the same dimensions, the one on the right (which is what I mean by hollow box) will be massively stiffer in torsion :

                                Ivbox.jpg

                                You can demonstrate this for yourself - if you take a cardboard tube from the middle of a roll of toilet tissue and try and twist it it's fairly strong, if you cut down its length so it's now a C-section and twist it it becomes much more flexible, because the cut edges shear along each other. That is like this: very stiff when the tube is intact, cut along the red line and it becomes very flexible:

                                tube.jpg

                                Round tubes are particularly good in torsion, but are less good in bending (flexure) unless the bending is equal in any or all directions. Round tubes are also difficult to join to. Rectangular tubes are nearly as good in torsion, but easier to join (though not as easy as 2020). So when I said 'hollow box' I just meant a rectangular tube.

                                The 2020 sections do have a small hollow part in the middle, but it's not very big. That's why if you don't need the ease of connections, it might be better (but less convenient) to use a section that's more tailored to what you require (but you will need to drill holes for nuts and bolts, possibly use blind fixings etc). On balance, I'd probably stick with the 2020 range of sections, but (as previously noted) go up a size if worried about stiffness.

                                A Former User? o_lampeundefined 2 Replies Last reply Reply Quote 0
                                • A Former User?
                                  A Former User @achrn
                                  last edited by

                                  @achrn said in An "hardware" advice for linear rails:

                                  @thedragonlord said in An "hardware" advice for linear rails:

                                  Thanks again! Just a last question....what's a hollow box?

                                  I mean a rectangular tubular member.

                                  This is returning to a comment made up the thread - 2020 pultrusion (and similar) is good in lots of ways, but it's not the best from either a sructural strength or stiffness point of view.

                                  In general terms, for resting bending you want material spaced away from the centre of the section - so for bending in one direction only you end up with 'I' beams that have chunky flanges and tall narrow webs that are mainly just there to hold the flanges apart but acting together. If you have similar bending forces in both directions you want flanges in both directions, so you end up with a rectangular tube, or box.

                                  The other big win for tubes / boxes is that closed hollow sections are much much better than 'open' sections in torsion. So of these two sections, if they had same quantity of material and the same dimensions, the one on the right (which is what I mean by hollow box) will be massively stiffer in torsion :

                                  Ivbox.jpg

                                  You can demonstrate this for yourself - if you take a cardboard tube from the middle of a roll of toilet tissue and try and twist it it's fairly strong, if you cut down its length so it's now a C-section and twist it it becomes much more flexible, because the cut edges shear along each other. That is like this: very stiff when the tube is intact, cut along the red line and it becomes very flexible:

                                  tube.jpg

                                  Round tubes are particularly good in torsion, but are less good in bending (flexure) unless the bending is equal in any or all directions. Round tubes are also difficult to join to. Rectangular tubes are nearly as good in torsion, but easier to join (though not as easy as 2020). So when I said 'hollow box' I just meant a rectangular tube.

                                  The 2020 sections do have a small hollow part in the middle, but it's not very big. That's why if you don't need the ease of connections, it might be better (but less convenient) to use a section that's more tailored to what you require (but you will need to drill holes for nuts and bolts, possibly use blind fixings etc). On balance, I'd probably stick with the 2020 range of sections, but (as previously noted) go up a size if worried about stiffness.

                                  wow, thanks for the explaining! absolutely clear! May I ask you if you are a teacher in your life? thanks again

                                  achrnundefined 1 Reply Last reply Reply Quote 0
                                  • mrehorstdmdundefined
                                    mrehorstdmd
                                    last edited by mrehorstdmd

                                    If you want to mount linear guides on rectangular tubing, you can print a tool that holds nuts that are spaced to match the holes in the linear guide. Drill holes in the tube, slide the tool filled with the nuts into the tube, screw the linear guide down, then remove the printed tool. Bob's yer uncle!

                                    Use nylock nuts or include star-type lock washers and the nuts will never loosen.

                                    alt text

                                    https://drmrehorst.blogspot.com/

                                    1 Reply Last reply Reply Quote 3
                                    • achrnundefined
                                      achrn @A Former User
                                      last edited by

                                      @thedragonlord said in An "hardware" advice for linear rails:

                                      May I ask you if you are a teacher in your life? thanks again

                                      No, not enought patience to be a real teacher.

                                      I'm a structural engineer, but I do spend some of my working life explaining engineering topics to lawyers, so 'sort of', in that I sometimes get paid to try and explain things clearly.

                                      1 Reply Last reply Reply Quote 0
                                      • A Former User?
                                        A Former User @fcwilt
                                        last edited by

                                        @fcwilt said in An "hardware" advice for linear rails:

                                        @thedragonlord

                                        Hi,

                                        Could you send me a STEP file of the gray parts holding the pulleys?

                                        There is a arrangement I want to try out and post here for you to look at.

                                        Frederick

                                        I'm curios, what sort of arrangement were you thinking?

                                        fcwiltundefined 2 Replies Last reply Reply Quote 0
                                        • o_lampeundefined
                                          o_lampe @achrn
                                          last edited by

                                          @achrn
                                          Would you say, it'll be benefitical for existing printers made from 2020 extrusion to cover the unused T-slots with flat aluminum strips? Superglue works well on aluminum.

                                          achrnundefined 1 Reply Last reply Reply Quote 0
                                          • fcwiltundefined
                                            fcwilt @A Former User
                                            last edited by

                                            @thedragonlord said in An "hardware" advice for linear rails:

                                            @fcwilt said in An "hardware" advice for linear rails:

                                            @thedragonlord

                                            Hi,

                                            Could you send me a STEP file of the gray parts holding the pulleys?

                                            There is a arrangement I want to try out and post here for you to look at.

                                            Frederick

                                            I'm curios, what sort of arrangement were you thinking?

                                            I will post a picture.

                                            Frederick

                                            Printers: a E3D MS/TC setup and a RatRig Hybrid. Using Duet 3 hardware running 3.4.6

                                            1 Reply Last reply Reply Quote 0
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