P3Steel Build Log (#07) – Y-Axis Carriage and Belt

By chunkyadmin,

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  Comments: 8

Y-Axis Carriage

Now that the clamps are sorted it’s time to fit them to the blank y-carriage, as seen below. The 2.5 DXL frame uses four points to fasten bearings, some holes in the middle for the y-axis belt tension block and the bed screws holes at each corner. The middle “sticky-outy” part seen below on the left is used to secure the heated bed cables, or offers an additional mounting hole if your print bed plate as additional mounting points. The 2.5 DXL frame (along with the other versions) also comes with a thin bar which I am not too sure what it’s used for. From what I have seen, I thin it’s for a bed extension or to add additional mounting holes on the other side of the carriage. Either way, for a standard 200mmx200mm square bed which I am going for – you don’t appear to use it. Add a comment if you know what that part is correctly used for?!


I digress..! Fasten all the plastic parts to the carriage as shown below. I have chosen to keep the retaining screws facing the same way, and facing forward so they are easy to access if they need fastening in the future. Then insert the two 350mm length smooth 8mm rods. They should slide up and down in the bearings, and with probably more resistance than you think. From my experience with my bearings, printer clamps and smooth rods, they were not as smooth as I thought they would be, but once mounted and secured they seemed to loosen up and start to move more freely. So don’t be alarmed if they feel really stiff, you’re going for noise reduction with these bronze sintered bearings more than reduced friction.


You then need to eyeball the rods to the rod mounts on the frame to make sure you have’t done something catastrophic and they don’t match up, or they point away at some crazy angle. Something like below:


Now I had to start feeding the rods through the rod mounts in the frame. These holes are cut precisley at 8mm, so this is a test of how well your frame was cut and the quality of your smooth rods! You may also have some layers of paint on the inside of these hole on the frame – I filed them down to the metal, clearing the paint away. According to the RepRap wiki on the build process you whack the rods with a rubber hammer until they go through. I went with a “turn and wiggle” method which eventually worked and the rods began to push through. This did however cause the mounts to become loose, so I would stick with the rubber hammer method – more on that in the next post!!


You need to keep your rods straight and parallel and true to the frame, easy with just two hands, also while holding the heavy y-carriage…. 🙁 Keep going until the rods reach the middle, then you need to “thread” off the y-carriage from the rods and feed it back onto them from inside the frame, as per below:


Once it’s fed back onto the smooth rods, do the two-handed-hold-and-hammer-and-move-and-keep-straight-and-push technique till the rods meet the other end of the frame. This should be easier as the rods slide through. You may meet some resistance on the other side on the new mounts, again due to tolerances, paint layers etc – but just line them up and hammer them home. The rods will now be in place, holding the y-carriage up which should now move back and forth… it’s starting to become a printer and not a heap of metal and plastic parts!


Y-Axis Belt Tension Bracket

This little part below is the belt tension bracket, I want to say ‘tensioner’ – but my auto-correct keeps having a paddy at me. This is the adjusted for the y-axis belt and allows you to tighten and slacken the belt to fine tune the axis movement. Another part redesigned by Toolson and is far from the original steel part cut from with the frame. From what I have heard – the steel part is next to useless for managing the tension on the belt. So with every other aspect of this printer I blindly wisely follow those with working knowledge and experience of the printer and improve on it! You may have noticed it in previous image and clips from my P3Steel Build Log playlist on YouTube, it’s been attached for some time, but it fastens as per below two images. I don’t think it matters which way, as long as it runs along with the smooth rods. You need clearance from the bottom of the main frame section which lies beneath it, but my setup seems to be OK and it never hits it (see final images below to see what I mean).



When the carriage and rods are in place and the belt tension(er) is in place it’s time to hook it all up to the motor – time to belt up!

Click on the next page to keep on reading to see how I got on installing the belt and the whole installation video time lapse!

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  Comments: 8

  1. Hey, i just recently ordered a p3steel frame from orballo and i was wondering, is the Y carriage heavy since its made from steel?

    I was thinking if i should just get an aluminium carriage to minimize the weight.

    Also, whats the hand drill thingy i have seen you use on your videos to size the holes?

    • Hi!

      The y-carriage and bed is heavy, the steel frame for the bed doesn’t help. You can get aluminium bed frames, which are usually cut in 6mm Alu. Not tried one yet, but I would like to reduce the weight of the y-axis to help with speed and reduce vibrations.

      The hand drills are actually 3D printed “handles” for drill bits. You can find and download them on Thingiverse – https://www.thingiverse.com/thing:91035, but if you search “Drill bit handle” there are some other designs. If you have a drill with controllable speed, I would recommend that too, the hand ones get a little slow and boring!

      Best of luck with the build!


      • Hey, thanks for the quick answer!

        Hows the bronze bushings working out? I think i read somewhere that you noticed some slop developing on the Y axis. (This could also be thanks to the heavy carriage?)

        Cant wait for the steel frame and a printer that doesnt feel like its gonna snap in half when you touch the top of it , i currently got an aluminum extrusion i3 type printer and it feels like (havent physically screwed it to a table tho) no matter how i brace it the Z frame still flops all around.

        • Ahh well yes – I swapped out the bronze bushings for some standard LMU88 bearings as there was becoming too much slop… I could rock the bed up and down and see the gap between bushing and rod.

          I think the tiny 15mm bronze bushings are too small for the y-axis with the bed frame, heated bed etc. Toolson has never reported any issues, but maybe my bushings were a little too cheap and soft? It’s been running great on the LMU88 bearings ever since, I even adapted Toolson’s bearing clamps to work with the nut plates so the hex top was facing down for easier replacement. My next step would be to buy some Ultimaker sizes bushings (30mm++ I think??) and see if they hold up better or worse? I am happy though, so it’s at the back of the list!

          The P3Steel is a beast!! You could probably sit (a child at least!) on the frame and it wouldn’t move an bit. It’s a little overkill to be honest, but if you want a solid frame, 3mm steel beats Aluminium profile any day!!


          • By LMU88, do you mean LM8UU?

            Do you still have the STLs for the clamps, im presuming they fit for a 15mm by 24mm bearing, if you do, do you have them shared somewhere?

            Havent printed the bearing clamps yet so this would the be the perfect opportunity for a nice one 😀

          • Haha yes, too quick typing! Those too 😉!

            I have a half written blog post about it, but someone else has also asked me about the STL, so it is here…. https://www.chunkymedia.co.uk/wp-content/uploads/2017/04/p3steel_tooleon_lmu88_mount_remix.zip It’s almost the same, but the hex nut indent is no longer there so it allows for a screw/bolt to go in that way and butt up against it, with the nut being held in the nut plate on the other side. Think the hole spacing was slightly different too.

            Print them flat if you want them to look nice and you trust your layer adhesion, as over tightening on the fastening screws will force the plastic clamp to bend over the bearing slightly. Or print on it’s side so the layer lines follow the force path and it shouldn’t split at all.


  2. do you have bushings stl?

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