Hook and Loop Variance and Tolerances

Hook and loop fasteners are a handmade fabric that is woven. Because of this, it does not fit into tight boilerplate tolerances a lot of drawings might require. Simply playing with the material might be enough to take these products outside of tolerances set by drafting software that is used to working with machined metal parts. Despite these limitations, there are still very reasonable tolerances and variances for hook and loop products.

Drawing Tolerances

Most of the drawings we receive from customers include boilerplate tolerance fine print that requires measurements to be "+/- 0.02 Inches to the first decimal, +/- 0.01 inches to the second decimal, and +/- 0.005 inches to the third decimal" which is reasonable for rigid machined metal, but doesn't really apply to a handmade woven fabric. Additionally, since the material itself is pliable and malleable, a machine or die cannot strictly measure its length or width to these tolerances.

Metric to Standard Conversion

Another complicating factor is that much of our hook and loop products are manufactured in metric, using millimeters. This means that the conversion to inches may be slightly off. This is not typically noticeable, although it can be detected in wider widths. For example, 1" wide material is sometimes manufactured to 25mm even though 1" equals 25.4mm. That 0.4mm is very hard to detect, but on a wider width like 4", the material might be manufactured to 100mm even though 4" equals 101.6mm. That 1.6mm translates to 1/16".

Hook and Loop Width Tolerance

Hook and loop manufacturers typically err on the longer side, but there are instances where material can be up to 1/16" narrower than the intended width. Conversely, sometimes a 4" wide material is measuring the usable hook or loop, and so the selvage edge that runs along either side of the usable hook or loop would be added onto that, measuring up to 4 3/16". This can vary from manufacturer to manufacturer. Typically, we try to keep our width tolerances within 1/16" on smaller widths and up to 3/16" on widths of 4" or more.

Hook and Loop Cut Tolerance

We do a lot of converting at HookandLoop.com, which involves cutting these products to length. Our standard tolerance for cut products is 1/16". Most of our cuts fall well within that tolerance, but occasionally on longer cuts or very small cuts, the natural flexibility of a woven material makes it difficult to hit a desired length exactly. This is why we allow a tolerance of up to 1/16".

Adhesive Release Liner

Sometimes the adhesive backed hook or loop will raise up off of the release liner periodically. This is called tunneling. Tunneling is an ever-present issue in manufacturing hook and loop and does not affect the product's performance. Tunneling can happen when the release liner is not pulled tightly enough during the blocking process, when they apply the adhesive and release liner. Our warehouse is temperature controlled, so the tunneling is not an indication that the material was stored improperly or anything else that might affect its performance. However, if it is causing a problem, you can report it to us. We may require a 1 yard sample from the lot reported.

If you have any questions about our tolerances or the variance in specific hook and loop products, please email us at info@hookandloop.com.