In the last few years there has been a very quite resurgence of direct drive; gearless; or otherwise known as toothless ratchets that use bearings instead of pawls and teeth.
These types of ratchets need nearly 0 degrees of arc to engage. What this means is that any degree of movement in the ratchet will provide a directional result in the fastener.
Conventional toothed ratchets always need a certain degree of movement before the next tooth is engaged. The higher the tooth count, the lower the arc. There is a diminishing return of arc reduction per amount of added teeth. Even at 120 teeth, the arc is 3 degrees.
To get down to 1 degree of arc with a toothed ratchet would require 360 teeth, something that is impossible because the teeth would be just too fine.
Even though bearing based gearless drive ratchets may seem like new technology, they aren’t, BOG produced a gearless ratchet as early as 1929, and blackhawk as early as 1931 (patent 1936640).
With the recent resurgence the likes of Kobalt and Snap-on (model Fzero) are making gearless ratchets.
Some of the primary reasons why gearless ratchets never really took off in decades past is because they were more expensive, bulkier and didn’t provide the direct feedback to the user that a toothed ratchet would to allow the mechanic to ‘feel’ that they were turning the bolt. With a gearless ratchet; sometimes unless you are looking at the fastener it is hard to really tell if the bolt is spinning or if you are just moving the bolt back and forth (once loosened).
The resurgence has primarily come about because of modern cars and mechanics needing to work in more and more confined spaces (similar reasoning for tool makers striving for higher toothed ratchets).
One fundamental problem I have with gearless ratchets currently available from the likes of Snap on and Kobalt is the size of the heads:
In many cases, if the space is tight enough to need less than 3 degrees of arc, it is also likely very tight in needing a small ratchet head.
After much research here are the options for gearless ratchets that have small heads:
1. Titan (18202), Sealey (AK561, AK562, AK563. AK5661), Stna (STNGR14, STNGR12, STNGR38, STNKB14) gearless ratchets – The head is thin in both width and depth because of a push through drive design (for direction changing). All three brands (Titan, Sealey, STNA) are supplied by the same third party.
Just remember, not to get this ratchet jammed in somewhere that you would need to change directions to remove as its a push through type ratchet.
2. Hi-lok aerospace gearless ratchets by Omega Technologies (RR40S-SP, RR40SP, RR400SP) – the ultimate tiny head for the most confined of spaces; these ratchets were designed to be used in the aerospace industry in confined spaces where arc angle was limited. One fundimental limitation with these ratchets is their max torque is only about 150 in/lb or 12-13 ft/lb for the 1/4 drive size. Perfect to finish removing already broken loose bolts or for removing bolts that aren’t tightened to a high torque. Although, the working torque is 150 in/lb and in a pinch it could probably handle substantially more.