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Thread: Exfil Rail 2.0 mod for Unity Tactical Mark 2.0 Kit

  1. #1
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    Exfil Rail 2.0 mod for Unity Tactical Mark 2.0 Kit

    I bought a Unity Tactical Mark 2.0 kit when it first came out, to attach Peltor Tactical 100 earpro to my Exfil LTP, but they sat way too low on my head to be usable.

    PXL_20210419_192040469_1.jpg

    I emailed Unity about it, they told me they were aware of the problem, and that my solutions were to use more padding, or to cut the wires to be shorter. From that above pic you can see that I've adjusted it as high as it could go on the straight wire, the only area to cut would be above the bend, which would mean I would have to rebend it myself and probably fail to get the same angle. They also said that they were out of stock on the original Mark kit, so I could not exchange mine for the previous model.
    A follow-up email from them did say "With that said, we are looking into possible design updates to fix this issue."

    In the meantime, I designed my own solution in Fusion 360, using the 2.0 rail to mount the Unity adapters and bring them higher to my ears.

    PXL_20210419_192954982_1.jpg

    The pic below shows the base Unity method on the left, my mod on the right.

    PXL_20210419_192558163_1.jpg

    I use two separate pieces for this, a shorter one towards the front, and a taller one at the back. They each hold a 10-32 stainless hex nut (same size and threads as the hex nut in the helmet's rail).
    I dimensioned them to fit a Hillman Group 316 stainless 10-32 hex nut (I got mine at Ace Hardware). They fit snug enough to not fall when oriented upright while installing.

    This pic shows the underside of my pieces, with the hex nuts visible.
    PXL_20210419_185806075_1.jpg

    And the tops
    PXL_20210419_185715027_1.jpg


    To install, just slide the pieces in above the original mounting location. The corners are chamfered to slide into position, I have made the top chamfer 3x as large as the bottom one to easily tell they are oriented properly before continuing.

    I used the 7/16" 10-32 screw included with the Unity kit for the front piece, and a 1/2" long screw for the rear piece (the stainless ones in the pictures)

    Start with the rear screw. Get 2 or 3 threads engagement, just the bare minimum to hold it, then move to the front. After you have a couple threads on both, torque to a max of 10 in-lbs as with the Unity kit.

    The critical dimension for me was for the hex nut to sit snugly, so I opted to model/print that oriented vertically in the printer. The top and bottom of the pieces are both angled when printed, so they don't print as smoothly, at least with my Ender 3 V2.

    The rough edges do not really matter, the bottom is just there to help keep the pieces in position when installing it. After tightening, the bottom does not make contact with anything. I have installed/removed these pieces a bunch of times to see if I could break anything, it all holds up. If Murphy were to strike and the plastic would crack, it just needs to remain in position while being compressed between the helmet rail and the hex nut. Even if that didn't happen, the hex nut would not fit through the rail, so the most that would happen is some wobbling.

    Make sure to enable supports, and keep the hex nut horizontal when slicing (or put another way, align as if a screw through the hex nut would be oriented vertically, upside down). I just hit it with a file before installing to remove the supports and clean up some of the rough edges.

    https://www.thingiverse.com/thing:4833567
    Last edited by Mike Miller; 04-19-21 at 18:41.

  2. #2
    Join Date
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    Another pic showing the angle of the original installation threads compared to my piece

    PXL_20210419_185546781_1.jpg

    Another pic attempting to show the larger chamfers oriented to the top when installing
    PXL_20210419_191653471_1.jpg

    A pic showing proper orientation in Cura (for me this means no changes, just accepting the model's orientation as is)
    Screenshot_20210419_174701.png
    Last edited by Mike Miller; 04-19-21 at 16:52.

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