Plastic Snap Troubleshooting Guide

How do I use plastic snap pliers?


After forming a snap, most of the prong is squished flat, but some of it squished off to the side.

  • If they snap together fine, this is not an issue.  The pliers can be used again to compress the part that did not compress. Consider removing the rubber head to get a better view of the area to be compressed.
  • Make sure the correct die is in the base of the pliers.  Setting size 20 (T5) snaps with the size 19 (T8b) or size 16 (T3) die installed will often cause the cap to slide off to the side during forming.
  • Take the rubber head off of the setting rod.  Place a cap and stud in the die tray (with no material in between).  Slowly squeeze the pliers and look at the rod tip as it descends (you will need to watch it from the front and the sides).  If it appears to be closer to one side, loosen the screw on the die and twist the black die until the cap prong is centered well.  Tighten the die screw and consider placing a mark on the die to aid in future alignment.
  • Make sure the correct setting rod is installed: 

    o    For size 14/16 snaps, the standard setting rod (with the smaller inside diameter) should be used for both studs and sockets.  If the larger rod is used with size 16 snaps, it will damage the stud/socket.

    o    For size 20 snaps, sockets may exhibit this behavior if set with the standard setting rod.  The wide setting rod will likely cause the desired result.  Size 20 studs must be set with the standard setting rod; the wide setting rod will damage the stud.  We tend to leave the standard setting rod in the pliers for both studs and sockets, as it is easier than switching them out or keeping two sets of pliers on hand, but the wide rod will set size 20 sockets better.

    o    For size 19/22 industrial snaps, the wide setting rod should be used.  The narrow setting rod will not sufficiently spread out the cap prong.


    After forming a snap, the stud and socket look good, but they do not "snap" or have a weak hold.

    • Check that the stud and socket are undamaged.  If the stud or socket gets pinched by the setting rod, they will not snap well.  Damaged studs or sockets will need to be replaced.
    • Size 14/16 studs and sockets look similar if you have not seen them before.  Make sure you are not trying to snap two studs or two sockets together.
    • Size 14/16 snaps are particularly sensitive to material thickness (as are long prong size 20 snaps).  If there is not enough material between the cap and stud/socket, the prongs from each side can provide too much plastic bulk in the middle of the snap.  This will cause the snaps to repel themselves from the inside.

    o    Test if this is the case by taking an unformed stud/socket and snapping it to the formed one.  If it sticks well, that indicates there is not enough material between the cap and stud/socket.

    o    Try doubling up the material in between the cap and stud/socket.  That is often sufficient to overcome the plastic bulk between the parts (i.e. 1 layer of ribbon is often not enough to keep size 16 snaps from repelling themselves, but a ribbon loop that has 2 layers of ribbon between the snap is often just fine).

    o    Try snipping the tip off of the cap prong before forming the snap.  This will reduce the amount of plastic in the middle.


    The tip of the snap bends over instead of compressing.

    • Check that the correct die is in the pliers.  If the T3 (Size 16) die is in the pliers while forming a T5 (Size 20) snap, the snap will sit higher in the die and will often shift during forming.  This will cause the tip to bend over instead of compressing.
    • There may be too much material in between the cap and the stud or socket.  If the cap cannot compress, it will often bend over.  Widening the hole that the prong goes through (bigger than the awl makes by default) may help by allowing the stud/socket to descend more readily.
    • The cap may have a prong that is too long for amount of material.  This is likely to cause problems even if the snaps were to form, as the extra bulk from the prong will likely cause the snap to repel itself from the inside.  Try snipping the tip off of the cap prong to make it shorter before forming the snap.

    When the snap was formed, the back of the cap cracked.

    • This is most frequently caused by having the wrong die cup installed in the pliers.  If the die cup is too small, the snap will bridge the edges and may crack.
    • If using a press (instead of pliers) with an extension handle for greater leverage, the pressure exerted on a snap can be substantial.  Consider pressing on the handle closer to the pivot bolt to lessen the pressure applied.


    After forming a snap, the tip of the cap prong was shorter, but it did not compress.

    • There is too much material between the cap and stud/socket; it cannot form.  If the amount of material cannot be reduced, a press may be required to set the snaps and/or longer prong caps may be required.


    After forming a snap, the cap has a little bump in the middle.

    • Make sure the correct die is in the pliers.  Using a die that is too small creates a gap under the cap and allows the prong to push downwards before flattening.


    After forming a snap, the stud/socket comes off (cap and stud/socket separate).

    •  The half of the snap that came apart was not successfully formed.

    o    Make sure the correct die is in the pliers.

    o    Make sure the stud/socket are not flipped over.  The flat side should be against the material.

    o    If there is too much material between the cap and stud/socket, the point of the cap will not be able to squish sufficiently to keep the stud/socket on.

    o    Try reducing the number of layers of material between the snap.

    o    Try making a bigger hole (larger than the awl makes).  If the stud/socket start to form too high up, there will not be sufficient prong to form the snap.  Allowing the stud/socket to more freely slide down the prong will help.

    o    Try increasing the pressure used to form the snap.  If pressing harder is not an option, try one of these options:

    • Place a piece of chipboard under the die in the bottom of the pliers.  That will bring the die cup closer to the setting rod and allow more pressure to be applied to the snap.
    • Take the rubber head off of the setting rod.  That will allow more direct pressure to be placed on the prong.  Watch carefully when setting the snap, as the rubber head helps center the setting rod.

    o    Use a press instead of pliers.  Presses exert considerably more pressure and can set snaps in thicker materials.

    o   If none of the options above work, consider purchasing longer prong snaps that are able to handle the bulk that is between the snaps.


    When the snap was formed, the inside of the socket/stud broke.

    • The rubber head on the pliers serves two purposes.  The first is to center the setting rod, but the second is to distribute force on the outside of the stud/socket and push it towards the cap.  If the rubber head had been removed to try to set the snaps in thicker materials, it is likely that a longer pronged snap will be required.
    • If using a press (instead of pliers), too much pressure can push through the inside of the stud/socket.  It takes a little practice to get the feel for the correct amount of pressure.


    After forming the snap, it looks good, but the cap tip has a rounded ball shape instead of a swirled pattern.

    • There are several manufacturing methods for setting rods.  Setting rods with bull’s-eye tips often exhibit a swirled pattern.  Setting rods with concave tips result in a rounded ball in the middle of the finished snap.  Both tips work equally well.


    Have plastic snaps, buckles and clips been tested against harmful substances?


    Still need help?

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