Ladder Lock – Zipper Zoo.net

LADDER LOCK ADJUSTER

a bagmaking essential

Rest assured that your strap will hold tight! A ladder lock adjuster is a type of webbing/strap adjuster that allows you to adjust the strap length and automatically lock it to the chosen length. They are most often used to adjust the shoulder straps on a backpack or rucksack.

A ladder lock adjuster is made up of 3 gaps and 2 bars, giving it its ‘ladder’ descriptor. Unlike a regular strap adjuster that can move freely, a ladder lock adjuster creates a secure “lock” that will not accidentally slip or come loose during use. You can adjust it only at certain angles, and once set in place, it won’t budge.

You use two strap pieces with a ladder lock adjuster. One is a short, fixed-length strap piece to attach the ladder lock to the bag or backpack strap; the other is a longer piece that can be adjusted for length. Also, a ladder lock adjuster has a right side and a wrong (upside-down) side. It must be threaded correctly in order for the locking function to work.

It is also referred to as: backpack strap adjuster, ladder lock slider buckle

Size Matters

Ladder Lock Adjusters come in various sizes and dimensions. Common sizes range from 15 to 50mm (1/2 inch to 2 inches) in width.

When you buy a ladder lock adjuster, the size that is indicated refers to the inner width of the adjuster. This is the most important measurement since you have to match it to the width of the strap you intend to use. Your strap or webbing should be the same or slightly narrower than the inner width of the gaps.

Illustration of ladder lock adjuster sizing

Question: How do I determine the correct side of a ladder lock adjuster?

Answer: You’ll be able to try out the locking before securing anything permanently, so don’t worry too much about this yet!

Ladder lock adjusters typically have a curved or angled ‘tongue’ at one end. When upside-down, the ‘tongue’ rests on the table, and there is often ribbing at the base of the tongue that is visible from this side. The bar closest to the tongue is recessed/sunken compared to the other bars.

Flip it over so that the tongue and its closest bar are up away from the table. That bar often has visible ribbing from this view, and you won’t see ribbing at the base of the tongue here. This is right-side-up.

With the ladder lock adjuster right-side-up, you feed the longer strap piece from underside to the right side, and then back down to the underside. The excess strap hangs down from behind the tongue.

Question: How much tolerance is acceptable for a good strap-to-slider fit?

Answer: A deviation up to 2mm both up or down is generally acceptable for a good fit. For example, a strap that is 23-25mm wide will usually fit into a 25mm ladder lock adjuster. A larger size discrepancy can cause a strap to twist or bunch up on the sides.

Question: Does the strap thickness matter?

Answer: Yes. Ladder lock adjusters work best with webbing or very thin straps. Make sure to seal or burn the edges of synthetic webbing to keep it from fraying.

Common Styles

Ladder lock adjusters are most commonly available in plastic, but are also available in metal with various finishes for a higher-end look and feel.

How to Apply

Step 1

Gather your two strap pieces: longer for the adjustable side, and short for the non-adjustable side. Keep both the adjuster and straps right-side-up for all steps.