In May of 2018, I purchased a used fanny pack for $5.99 with the intention of modifying it into a chest pack. I figured it’d carry a VHF radio, binoculars, field notebook, Leatherman, my Samsung S8, maybe a Garmin 64S, and a handful of miscellaneous items. Since the first prototype, I’ve constructed a second chest pack. This time, out of a small, used Arc’teryx shoulder bag purchased for $4.99 (pictures below). Nowadays, I tend to wear a chest pack while in the backcountry whether it’s for work or fun. Pictures of both versions are below.
TLDR: find a small pack that’ll fit between your backpack’s straps, sew two loops of webbing on either side of the to-be chest pack’s base, sew/attach two small and sturdy male end buckles to either side of the chest pack’s top seam, and attach the corresponding female ends to either side of your backpack’s sternum strap. Buckles and short sections of webbing can be poached from dog harnesses purchased at thrift stores. Their hardware and materials are generally sturdier than what’s available at crafting/fabric stores—and much cheaper.
Version 1: I began by removing the waist belt and bar stitched two short lengths of 1/2 inch webbing to either side of the small pack, along the top seam. These were used to attach the male ends of two small buckles. Then, two lengths of hook-and-loop velcro were sewn along each side of the pack where the waist belt had been—these would secure the base of the chest pack to the backpack’s straps, preventing it from swinging back-and-forth as the user hikes. Two female buckles corresponding to those on the pack were attached to short lengths of webbing, double-backed onto themselves, creating two small loops. These were clipped into the sternum strap attachment points on the backpack’s straps. Using the chest pack: put on your backpack, clip your sternum strap, attach the chest pack to your backpack via the two small buckles, and velcro either side of the pack to your backpack’s straps. When removing your pack temporarily, you can detach one velcro strap and unclip one buckle, letting the chest pack hang—quick to reattach once you put the backpack on.
Version 2: The Arc’teryx chest pack doesn’t attach to the backpack’s straps. I passed a skinny chalk bag belt through the loops of webbing sewn into the bag’s bottom seam and clipped it around my torso. This way, I can take off the backpack without removing the chest pack—more convenient. I’d need additional webbing and two female end buckles to make it a standalone chest pack; it could then be worn underneath the backpack, completely detached. Pictures of Version 2 are at the end of the gallery below.