Carbon fiber rod diameter

  • I'm in the process of building a new delta, and will be using carbon fiber arms, likely with magnetic ball mounts. I use 304mm Huntley arms on my current printer, and have been happy with them.

    The new printer is based on dc42's blog, and will use 360mm arms. Haydn Huntley's sets all seem to use 0.230" (~5.8mm) diameter arms. I've read a few times where users of his 360mm arms wished they were a larger diameter, but that drives the cost up considerably (assuming he would make some with larger diameter at all).

    Is there solid reasoning behind the desire for larger diameter arms, or is it just speculative?


  • administrators

    I believe Haydn now makes 8mm (or possibly 10mm) diameter arms to order.

    When using longer rods especially, using thicker arms might reduce ringing by making the system stiffer; but this is just speculation.

  • I had Hadyn make me a set of 720 mm arms for a 600x620 print delta (1.5 meter towers with 1 meter linear rails).

    We discussed diameter. I suggested using carbon tubing who's INNER diameter matched the outer diameter of his delrin rod ends. He stated this was overkill, and stated that uses either .230" or 10mm o.d. carbon tubing, and that the 10mm would be more than enough for the 720mm rods.

    I've had those rods up and printing for some time. Very happy with the print quality.

    The printer was not quite finished in this photo; it shows the rods pretty well.


  • Thanks for the input, guys. I've since had a brief conversation with Haydn, and he stated that he hasn't had a single request for larger diameter arms in 360mm length or shorter. He did state he's done larger diameter with longer arms, though. He again stated that his normal 0.230" is plenty sufficient for 360mm & below, and likely somewhat longer, too.

    I did see on his site that he recommends a dab of lube in each joint (he applies with a Q-tip). I think I'll try that soon.

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