John James - RMLeatherSupply Harness Needles (Pack of 25) Blunt Tip for Leather, Quilting & Beadwork (Size 0 (1/0)) Review (2026)

What these needles are

This listing is a 25 pack of John James saddlers harness needles in size 0, also labeled 1/0, sold through RMLeatherSupply, measuring 57mm in length and 1.09mm in diameter. Like other harness needles in the John James range, these have a blunt or rounded tip rather than a sharp point, which is the standard design for saddle stitching, a technique built around pre-punched holes rather than the needle piercing the leather directly. The blunt tip also lowers the risk of the needle splitting the working thread or snagging on the opposing needle when two needles are passed through the same hole from either side, which is the core mechanic of saddle stitch and part of why it holds up better than a single-thread machine stitch on high-wear items.

Why the larger size matters

At 1.09mm diameter, size 0 is noticeably larger than the finer sizes in the John James lineup, and it is built to accommodate heavier waxed thread that would be a tight, difficult pull through a smaller needle's eye. This makes it a natural fit for projects using thicker cord, such as harness repair, heavy tool rolls, and belts, where a sturdier thread is common and a smaller needle would slow down stitching or risk the thread fraying as it is repeatedly pulled through. The 57mm length also gives slightly more room to work with when reaching through multiple layers of thick leather, which matters on bulkier projects like folded belt tips or multi-layer harness joints where a shorter needle can be awkward to maneuver.

Using them on typical projects

As with any harness needle, holes need to be pre-punched using a diamond stitching chisel, pricking iron, or awl before stitching, since the blunt tip is not designed to pierce leather on its own. Saddle stitching with this size works best when the stitch hole spacing and chisel size are matched to the thread and needle diameter, since holes sized for a much finer needle will feel crowded and difficult to work with a size 0 needle and its wider eye. Crafters moving up from a finer needle size to this one for the first time should expect thread threading itself to be easier thanks to the larger eye, while pulling stitches tight through smaller holes will take a bit more effort until the technique is dialed in.

How it compares with smaller sizes

Against a medium needle like size 002, covered elsewhere in this guide at 1.02mm diameter, this size 0 needle is close in scale but built specifically for the thicker end of common leathercraft thread, making it a better match for tool rolls, belts, and harness work than slim wallets or card sleeves. Compared with the finest sizes in the range, meant for delicate decorative stitching on thin leather, size 0 is considerably heavier and would look and feel oversized on small, fine-detail projects. Choosing between sizes mostly comes down to matching the needle to the thread weight already in use, since a needle too large for the thread makes for sloppy, loose stitches, while one too small will be a struggle to thread and pull through.

Who should buy this size

This size 0 needle suits leatherworkers regularly stitching with heavier waxed thread on belts, tool rolls, dog leashes, or harness and saddle repair, where the thicker cord these projects typically use needs a wider eye to pass through smoothly. It is also a good pick for anyone building a small range of needle sizes who wants to cover the heavier end of common leathercraft thread without special ordering a rare size. Skip it for fine, thin-leather projects like slim wallets or card sleeves stitched with light thread, where a smaller needle size will handle tighter, closer-set holes more comfortably and look more proportional to the finished piece.

Frequently asked questions