SISKA INC.

How to determine what eyelet / grommet is best suited to your application.

The success of your eyelet or grommet setting depends on selecting the proper size fastener for your application. The following variables should be known before selecting your eyelet or grommet.

1) What hole size am I looking for?
2) What is the overall thickness of the material to be eyeleted?
3) Is the material stretchy, flexible or rigid?
4) Do I want the eyelet to be highly visible in my work for decoration purposes?

Eyelet Dimension Terminology

The hole size in most cases can be easily determined. If the purpose of the eyelet or grommet is to provide support for a chord, draw string or metal hook, a slightly larger inside diameter (ID) or hole size is needed so the cord or chain can easily fit through it. Most eyelets sizes are listed by the outside diameter (OD) of the barrel. To determine the ID of the eyelet, take the OD and minus the metal thickness of the barrel twice. This will give you an approximate ID. Most grommets sizes are listed by the hole size (ID) so there is no need to figure this out. In most applications the eyelet or grommet if not there for pure decoration is there to serve a purpose. This may be re-enforcement of the hole or to bind two or more pieces of material together. In these cases the smallest eyelet that will perform the operation is usually selected as not to be the most pronounced feature of the application. In these instances a small hole as well as a small flange is desirable. If the eyelet is there for decoration purposes the size of eyelet or grommet hole and flange are a matter of personal preference.

Probably the most important factor in selecting an eyelet or grommet is the thickness of the material. The thickness and type of material will determine the correct barrel length of the eyelet or grommet. If the barrel length is too long the eyelet or grommet barrel will collapse or crack during the setting procedure. If the barrel is too short the eyelet or grommet will not set properly into the material resulting in a weak setting that will pull out. No two applications are alike and it is impossible to publish a specific standard as to just how much barrel length of an eyelet or grommet should be allowed to obtain a proper roll or scored setting. (For a description of a roll and score setting visit our die page). In rigid material usually less length is required than in softer or flexible material. In material that is soft or flexible more barrel length is advantageous so a wider roll or score setting can be used for added strength. If the material is stretchy or very thin as in a paper binding application a washer should sometimes be used for added holding strength. In stretchy material a wider flange is desirable. Where parts are to be assembled and left to rotate (as in a pin wheel) a longer barrel is required. As a general rule in selecting an eyelet or grommet the following chart should be helpful.

To select the proper length of an eyelet or grommet determine the overall thickness of your application including the thickness of a washer if one is used and add the additional length from the above chart. For a final determination after selecting an eyelet let us set some samples in your material (at no charge) to insure the proper length. If you are not sure what eyelet or grommet to use in your application send us your samples and we will be glad to set different fasteners for your testing and approval.

     

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