Strong Dog Leashes | Why Construction Methods Matter

Equipment failure? Dog leash construction methods matter when it comes to making strong dog leashes, especially when you're looking for leashes for large dogs that may be reactive.

Ensuring your hardware and your materials are strong enough is 2/3 of the challenge. The third leg in the "triangle" of selecting the best dog leash is the method that keeps it all connected!

There are two primary methods of construction for dog leashes and other equipment: Sewing and Metal Fasteners.

Sewing is my construction method of choice for strong dog leashes!

Sewing is more versatile, and easier to get consistent results.

A box stitch pattern spreads the force over a greater area of the nylon webbing leash material, and sewn equipment is easier for a dog guardian to monitor for wear & tear.

PROPERLY DONE, sewing can be superior to mechanical fasteners.

There are 4 sewing patterns for webbing that have been tested in the sailing industry; a bar tack, a diamond pattern, an “M” pattern, and a box stitch.

Image featuring four different types of stitch patterns used in constructing products out of webbing.

Out of the four, the box stitch is the one where testing resulted in the webbing failing before the stitching. [.pdf download of break test results from Sailrite]

I use box stitching for all of my webbing leashes:

#69 bonded nylon thread = 11 lbs tensile strength (TS)

@ 8 Stitches Per Inch (SPI), with Loop Strength (LS) of 1.5

SPI x TS x LS = 132lb/in

1" long box stitch on 1" webbing = 7.5" of stitching

132 x 7.5 = 990 lbs of strength for my standard box stitch

The second most common stitch used in leash manufacturing is the bar tack, typically done with a zig-zag stitch, but sometimes done with multiple rows of straight stitch.

Following the math above, the bar tack can provide strength equal to that of a box stitch, but with the force spread out over a smaller area of the webbing. A bar tack or any stitch using a zig-zag stitch has the “force” concentrated at the points of the stitching.

A zig-zag stitch with multiple layers of thread will also sit “proud” of the webbing surface, allowing an increased risk of abrasion of the top layers of stitching.

DIY Dog Gear

If you are looking at making your own webbing gear, I caution you that most home sewing machines (even the heavy duty ones) will struggle with the thickness of the webbing and the size of the heavy duty thread needed for secure webbing products.

You may consider hand stitching your webbing if necessary, it's not fast and not fun, but it is a good construction method for your dog leashes!

Metal Fasteners on Leashes for Large Dogs

BioThane® or Rope leashes more commonly use mechanical fasteners.

Rivets or Chicago screws often require a hole to be punched into the webbing material, reducing the effective strength of that material. 

red leather collar with decorative spikes
Decorative elements look great - but keep them for ID collars!

Products such as rope or BioThane®rope use metal fasteners such as clamps or sleeves. Most metal fasteners are a friction fit, but some do have “teeth” on the clamp that help the fastener maintain a grip on the materials.

Improperly set rivets and other mechanical fasteners can fail due to maker error. 

A maker experienced in setting mechanical fasteners can identify when they haven’t “seated” or “compressed” correctly, and can replace the fastener before sending their product out to the dog guardians. They should also be using a bench mounted manual or pneumatic press for consistent results.

DIY Dog Gear

Please use caution if you are looking to start making your own BioThane® or Rope products!  

Entry level makers or those making equipment for personal use frequently use handheld tools to start with before investing hundreds of dollars in professional press systems. Hand tools can be a challenge with applying sufficient strength to properly compress mechanical fasteners. If you're making a leash for a large dog, the last thing you want to have happen is for it all to come apart into pieces!

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