A reamer or awl is present on the back of nearly all larger Victorinox and Wenger models. The tools are typically used for punching or drilling holes in lighter material such as leather, canvas or wood. The terms are used somewhat interchangably, although technically the tools are slightly different, the awl being for punching/drilling holes and the reamer for drilling/enlarging holes.
The Victorinox versions are all now sharpened (ie reamers), whereas the Wenger versions are smooth.

Victorinox

The Victorinox tool started out as an awl, some people still refer to it as such, but Victorinox is currently referring to it as a 'reamer/punch'. The tool is usually located on the backside of the knife and may include a hole through the blade known as a sewing-eye. The 91mm backside version is 37.7mm long, with a sharpened edge of 22.8mm. It has a hardness rating of RC52, but it is not known if this applies to all versions of the tool.

The tool is also tapered so, as with any reamer, it can be used to enlarge a hole by twisting and scraping the edges of the opening. The sewing-eye can be used to push/pull a heavy thread through canvas, nylon, sail-cloth or any tough material the tool can penetrate.

In 1961 the original triangular awl was redesigned and given a sharpened edge, making it more suitable for use as a reamer. The sewing-eye was added to the reamer in 1985. There are currently (2022) three main designs/versions of the tool in production:

• The 91/84mm version with a sewing-eye, prior to 1985 it did not have a sewing-eye
• The 111mm liner-lock version that has no sewing-eye, the earlier slide-lock version had a sewing-eye
• The 93mm version on the Alox scaled knives, which is an inline tool with a totally different design

The Vintage 'Triangular' Awl - Closed

The Vintage Awl - Open

The 91mm 'Reamer' with no Sewing-eye

91mm Vintage Awl

The older original awl is easy to identify on a knife when folded. The awl is very visible and is triangular (tetrahedral) in shape, the bottom and inner surfaces are flat, while the outer face is rounded to conform to the scales. The inner edges are not sharpened, but they are not rounded either.
This was the design used on the original 1890 Swiss Soldier Knife.

93mm - Alox Models

The Alox scaled models don't have backside-tools, so the reamer is on the front-side and shares a layer with the main blade. This variation has a distinctly different shape/design with a more pronounced taper, and a right-angled bend at the top edge forming the spine of the tool. This bend aids in reaming of some materials and also serves as a catch to open the tool, rather than the typical nail-nick on the side of a tool. This version does not include a sewing eye and is the shortest length, but it has a sharpened edge of 29.9mm, which is longer than the 91mm version. On many materials this version is actually the most effective, or efficient, reamer.
NB: This awl is also included on the large 91mm collector models, the SwissChamp XAVT and the SwissChamp XXLT. It also features on the Wenger Soldat/Soldier, although the design varies very slightly from the Victorinox version. The Soldat is the only Wenger model to contain this tool.

108mm

The discontinued 108mm version of the tool really is more of an awl, and does not contain a sewing eye. The tool is slightly longer (48.6mm), more pointed, and has a slightly less sharp edge.

111mm

This version of the reamer has a shape closely matching the 91mm version, but is larger. The original version on the 111mm slide-lock models contained a sewing eye, while the reamer in the newer 111mm liner-lock models does not have the sewing-eye. It measures 37.3mm with a sharpened edge of ~25mm (~23.7mm for the version with the sewing eye).

93mm Reamer

108mm Reamer

111mm Slide-lock Reamer

Wenger

65mm

The Wenger Pocket Tool Chest includes a small awl. This is a very unusual tool for the pocket/key-chain models, and the PTC is believed to be the only model that contains this tool. There was no equivalent Victorinox tool in this size.

85mm

The Wenger tool is much closer in design to a regular leather awl without any sharped edges. The lack of sharpened edges can be an advantage at times, for instance helping untie knots.

120/130mm

Standard Awl:
These are scaled up versions of the Wenger 85mm awl

'Mike Horn' Reamer:
This version first appeared on the Mike Horn Ranger model and has a completely unique design. It has a cylindrical 'tube' that has a sharpened edge and works well for drilling/cutting holes in wood and softer materials.