I gave a talk on brace bits for Bench Talk 101 this week (https://www.youtube.com/watch?v=qKdIYOQL00s), but due to time constraints I had to skip one major family of bit. The Gimlet Bit. These bits look like traditional hand powered gimlets and are mostly used for drilling pilot holes for nails and screws. They go by many names, Swiss Pattern gimlet bits, German pattern, Persian, Twist, and my favorite “Cobra Bits”.

While popular in the UK and USA they where generally imported from Europe and seen as a cheap, utilitarian bit not even worth sharpening when dull. The quality of manufacture generally reflected the price point, with some bits literally unraveling their twist under heavy use.

Gimlet bits are generally small, with sizes typically ranging from a 16th to a 3/8th of an inch. While primarily used for pilot holes, they leave a relatively clean entry and exit hole, and as the sides cut, if used with gentle pressure they tend not to wedge. This makes the larger sizes suitable for through hole boring and doweling work. The pointed tip and lack of spurs allow them to drill at extreme angles, making it possible to drill pocket holes.

Some classic woodworking sources suggest that Gimlet bits cannot be sharpened, but they can, and its not particularly hard. Any file narrow enough to fit within the twist can do the job. Just run it along the cutting side turning the bit in your hand as you go, and most gimlets will cut far better than when you found them. Only one side of the twist cuts in use, so that’s the only side you need to sharpen. There is also no point sharpening the twist after the largest part of the bulge, as it will never come in contact with the wood and cut.

The Gimlet bit is not a must have bit, but if you use tapered fasteners they are a fantastic bit to have in your collection. Even if you don’t and you have a few from a lot of old tools, give them a quick sharpen and try them out, you will find a good use for them sooner than you think.

A few useful links:

Bob Rozaieski on Sharpening Gimlet Bits https://brfinewoodworking.com/sharpening-gimlet-bits/

The Renaissance Woodworker Video on Gimlet Bits (Great demonstration) https://www.renaissancewoodworker.com/gimlet-bits-anyone/

My Brace Bit Talk on Bench Talk 101 https://www.youtube.com/watch?v=qKdIYOQL00s


Standard Gimlet bits in various sizes. Standard Gimlet bits in various sizes.


An exceptionally long set from my collection. Given the typical application is for boring pilot holes, I’m not sure why they where manufactured in this length. Long Gimlet Bits


The tapered shape of the typical gimlet bits makes them ideal for boring pilot holes for tapered nails, such as cut and roman nails. Tapered Nails


Sharpening a Gimlet bit. Sharpening a Gimlet bit


Gimlet bits in a 1932 Peugeot catalog, where they are described as “Swiss pattern” Gimlet bits in a 1932 Peugeot catalog


“Cobra” bits in a 1959 Marples catalog "Cobra" bits in a 1959 Marples catalog


“Screw bits” in a 1930 Tyzack catalog. "Screw bits" in a 1930 Tyzack catalog