I have a derivative of the P3Steel v4, which is not the Irobri design but another version (I'm not entirely sure which), from Poland: Frame Prusa I3 P3Steel v4.0 +RODS.

I have assembled the frame, following this guide, manual_p3steel_xl, only to be left with one part, which is the long thin rod, which has a small hole, only in one end (the hole is marked by the big arrow in the image below):

P3Steel v.4 frame parts

This part obviously goes into the slots at the bottom of the Z axis arms, as shown by the curved arrows.


  • Which way around does the part go?
  • Should the small hole be on the left or the right hand side, when looking at the printer from the front?
  • Also, what exactly is the hole for? Is it just for a zip tie, and to be used to keep the cables (maybe from the heated bed (power and thermistor)) tidy?

I have looked at a number of other photos and videos for the P3Steel frame, and none of them clarify which way around, or how, the rod should be fitted. The bar is either omitted completely, or the image is not clear enough to show the correct orientation.

The guide does not show this part being used, although it clearly shows the slots for it in the Z axis arms, in a number of the pictures, such as here:

Screenshot of assembly guide showing slots for metal bar

  • $\begingroup$ I think you are overthinking it... Unless there is a reason for the small hole, then it is likely just the result of the Manufacturing process. Then there is the tried and true method of plugging it in and seeing if it works! $\endgroup$
    – StarWind0
    Jan 15 '17 at 9:52
  • $\begingroup$ @StarWind - I know what you mean, but it is not an artefact from manufacturing, it is in the part specification (I'll try to dig them out). Also, I could just put it in and hope for the best (which is actually what I have ended up doing, to be fair). However, to change it would then require some major dismantling - in order to just reorient it. That's the only reason why I want to get it right the first time around :-) $\endgroup$
    – Greenonline
    Jan 15 '17 at 12:08
  • 1
    $\begingroup$ If these frames are ever sold powder coated or plated then that hole could be present to hang the part for said processes as most other parts appear to have a hole or easy way to hang. Otherwise maybe it's a hole to route your motor wires through to prevent them getting in the way of the carriage or to run a cable tie through to hold wires? $\endgroup$
    – tjb1
    Jan 17 '17 at 12:26
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    $\begingroup$ You can see the placement of it on the ebay pictures, small hole is on the right side when looking from the front. $\endgroup$
    – tjb1
    Jan 17 '17 at 12:28
  • $\begingroup$ @tjb1 - Well spotted on the eBay pictures. Thanks. I hadn't noticed it before. $\endgroup$
    – Greenonline
    Jan 17 '17 at 12:43

This is half of an answer. I have finally received an answer from my supplier, which says:

Long thin rod is mounted as in the photo. I do not know what is a small hole.

So the small hole is still a mystery.

Here is the photo that was included with the message (which confirms my placement, just not the orientation):

Long thin rod placement


As tjb1 points out in his comment, the hole can be clearly seen on the right hand side of the bar, in the eBay photo:

Photo of P3Steel

  • 1
    $\begingroup$ If the hole isn't used by anything and everything else works, I'd say just ignore it. It may have been added during prototyping phase and never removed from their drawings, or could have been added as a datum feature for their manufacturer (though this seems a bit extreme for a part like this). It may also be a mounting hole for a set of features or upgrades that aren't yet available or were ever followed through on. $\endgroup$
    – Diesel
    Jan 17 '17 at 16:34
  • $\begingroup$ @Diesel - "datum"... For confirming that the printer is set geometrically square, flat etc.? $\endgroup$
    – Greenonline
    Jan 17 '17 at 16:36
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    $\begingroup$ It's possible. I was thinking more for the the manufacturing of that specific part though rather than for the full assembly. I've sometimes added simple features to parts specifically for making measurements at final inspection easier. Generally they're ridiculously complex organically shaped parts that are hard to measure, which is why I don't think that's the case here. My guess is that this hole is either an artifact of a previous design that was never removed, or a mounting point for a future upgrade if it isn't required elsewhere in the assembly. $\endgroup$
    – Diesel
    Jan 17 '17 at 18:25

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