Anycubic ‘D’ Predator Arms

The delta arms supplied by Anycubic are shocking. There are three main problems you will find with them.

  • They are not all the same length
  • The rod eyes on them can be slack
  • The glue holding them together comes unstuck

I have mainly had issues with them not being the same length and the glue coming unstuck. But I have used the glue issue to my advantage.

I would highly recommend removing the whole end from each arm. That’s the black tube that’s glued on the end and the rod eye.

I made a rod setter out of a piece of hardwood and a couple of M4 threaded screws.

The key is to reglue every arm you are using on your printer. The length between the mounting points on the eyes is 440mm. So I separated one end, and using superglue, fitted the end and set them all to the same length using my jig.

One arm was longer than the rest, to the point where I had to cut the carbon fibre tube down to be able to get the end piece set to the correct length.


  1. Hi Jay, being following your upgrades to the Predator. I have a Rostock Max V2 with a ton of upgrades, including Duet3D and FSR Bed sensors and, E3D Cyclops, 713Effector mount and Carbon Arms.

    Im thinking a cost effective upgrade would be to get a Anycubic and transfer all the bits I like/might be better from my Rostock. Any thoughts?

    Three of the many things about the Predator Im curious about:

    1: The Arms.. given the bed is 370mm diameter could the arm length be reduces from the huge 440mm units to increase build height? I see no reason they are that oversized (ie 400mm should be fine). Also it looks like it could print right to the edge unlike my Rostock.
    2: The Bed and their level sensor setup Im not a fan of. Can the bed be mounted (floating) to use FSR mounts?
    3: The arm to arm gap.. what is it vs say a Rostock Max, standard SeeMeCNC gap is: 55mm mid arm to arm.

    thanks for the great reviews and progress updates!

    1. The bed is actually 380 in diameter but the maximum area is offset by 5mm to give 370. I suppose you could reduce the arm length but you’d have to work out the shortest allowable length to still give you 20 degrees when effector is at it’s maximum distance from a tower. I’ve just changed my arms to magball ones and left them at 440. With the smart effector, my build height has reduced from 455 to 432.
      The bed has wings incorporated in it to allow it to be secured to the frame. You could mount FSRs under here if you designed a custom mount.
      And the arm gap is 64mm. Mine is back to the standard of 55mm after changing the arms.

      1. Cool, interesting.
        On the Arm length vs Angle, according to your Duet Config.g numbers and this calc:

        405mm is the ideal arm length, it still maintains 20degree angle on the extreme edge but gives you back 35mm build height.
        Stock is 455mm height with 30degree angle vs 493.8mm build height with 20degree angle.
        370mm X nearly 500mm height in a $600 metal chassis is kinda nuts!

        Direct Pre-set calcs

        Stock 440mm arms
        (some guess work, worked back from the firmware settings to guess the chassis dimensions)

        With shorter 405mm arms:

        1. That would put me near enough stock then with the smart effector.
          I’ve got mine all rebuilt. Just been fiddling with the trigger height etc to get that right.
          One great thing about the frame is that you can remove an upright without having to dismantle the frame. I was able to remove one upright at a time to change the motor and fit the new arm adaptors.

  2. Why did you have to change the motor?
    Also what arm adapters did you use? Does the carriage need to be changed to get to Seemecnc 55mm standard?

    Apologies if this is in a blog post too, just direct me to it!

    1. I haven’t written a new update yet so don’t worry.
      I changed the motors to go from 1.8 degree to 0.9 degree steps. This doubles the resolution of the machine.
      To change to 55mm, rather than change the whole carriage, the adaptor that the rods secure to can be changed. I’ll take some pictures and write a post about it this week.

      1. And what about the printing speed with that 0.9 motors? You can use the same before or is decreased drastically?

        It’s worthing (or you can appreciate too much) the change of the resolution? Do you have some pictures to see the before/after?

        I appreciate your blog because it’s very helpful for the people that we are looking to improve our machines šŸ™‚

        1. Unfortunately, since fitting the motors etc to the printer, I’ve pretty much been away with either work or on holiday. I’m back next Friday and intend to do a full write up then.
          But in short, speeds should be the same as we’re not too concerned about torque etc due to how light the effector and hot end is. 0.9 degree motors have long been advised for deltas throughout the community.

          1. Thank you, I just buy the predator and I’m looking forward for the best updates that I can do it.

            I will wait for your next updates with patience and I hope you enjoy your holidays

          2. For the moment I am back on the stock motors.
            When I get chance I will go with these.
            I’m aiming to build a new printer (a corexy) so any improvements bar the smuff for my predator may get put on hold.

  3. Okay the magball arm sounds good but where do I buy the magball and what size……

    Sorry newbie in delta printers šŸ™‚

      1. Thanks for your answer… Does it fit the stock printer setup then or do I need somthing else also ?

        1. I don’t think anyone has designed anything for use with the smart effector yet. I know Haydn is looking into it but it’s early days. Most people use then with the smart effector

          1. Okay sounds nice and easy…. Can you maybe post 2 picture how it is attaced on the printer part…. I have looked on the web but people just talkes about how great it is and shows the rods and prints…. Sorry this delta is new for me but surely a great printer that I love šŸ™‚

          2. I can but I’m currently in France until next Friday. If you’re ok to wait until then I will write a blog post about my recent upgrades

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