Hex Nut Pocket/trap

Discussion in 'Tips and How-tos' started by glackcadman, Dec 18, 2018.

  1. glackcadman
    glackcadman Member
    hi there
    I'm designing in hex pockets to match standard metric nuts and retain them during assembly. does anyone have any experience of 3D printing this feature, I have made the pocket with a 0.2mm clearance all round a standard nut size, but not sure if this is enough allowance.
    I was also thinking of additional small raised 'blips' on 2 or 3 of the side walls to retail the nut once it has been pushed in place.
    (probably the best solution would be to have a plain sample 3d printed with varying hex pocket sizes)
    if anyone has done this before, I'd be interested in your thoughts, I've attached an image for ref.
    regards

    hughcw
     

    Attached Files:

  2. Spitfire2865
    Spitfire2865 Active Member
    What material were you thinking of printing this in?
    Ive done similar with the WSF nylon material (white natural versatile plastic now) and all I did was make the hole exact size and force fit the nut in place.
    If you want to go with a metal print which has a shrink rate or one of the more brittle plastics, I would definitely advise you make it slightly bigger and expect to fettle the nut to fit.
     
  3. glackcadman
    glackcadman Member
    hi Spitfire2865
    thanks for the prompt reply, I was considering versatile plastic or professional plastic and not sure how close the fit would be bearing in mind the tols on hex nuts.
    but good to hear your experience.
    thanks again for the reply
     
  4. Spitfire2865
    Spitfire2865 Active Member
    Do you expect to be removing this captive nut at any point?
    If so, definitely give it a bit of wiggle room, depending on how big the nut is of course. If this is for something like M3 size, half a mil of slop 'should' allow you to easily remove it if needed but give enough grip to tighten in place.
     
  5. glackcadman
    glackcadman Member
    hi
    once it is in place, no need to remove, I was considering a couple of blips of the side walls of the pocket to ride over during installation and be enough to hold in place if screws are removed.
    I'm going to leave 0.1mm all round for the first set of components and see how that works during assembly.
    many thanks for your advice