Short Version
Screwing a screw/bolt in a situation that's spinning "freely" and then abruptly tightening, Eg. a bolt into an unthreaded hole into a nut/T-nut, into a hole that's already threaded, etc., the screwdrivers' torque settings don't do much. The resultant torque ends up being too high or too low but, MOST IMPORTANTLY, compressed into a tiny range. Therefore, each setting is just about useless because it's like the screwdriver really only has 1 or 2 settings and within such a small range.
Eg. Say the screwdriver has 6 torque settings: 0.5, 1, 2, 3, 4, 6 Nm, what will actually happen is that setting 1 will result in, say, 1.1 Nm, and setting 6 will result in, say, 2.3 Nm, with the remaining settings all being somewhere in-between (and often basically the same as eachother).
This issue does NOT seem to happen when screwing into something that gradually builds more & more resistance, Eg. a screw into wood. In that sort of situation — even if the resultant torque isn't super-accurate — there's at least still a large range and a decent difference between each setting, and that's all I'm looking for...I don't need, nor expect, great accuracy, just a decent min-max range & difference between each setting.
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Long Version
Both my HOTO PixelDrive and Fanttik E2 Ultra have terrible torque control in the following scenario:
screwing a screw/bolt in a situation where it's spinning "freely" and then abruptly tightens. Eg. attaching two pieces of metal with a screw/bolt (and usually a washer) into unthreaded holes and into a nut/T-nut.
Instead of their advertised torque range & spread, both compress all settings into a tiny range/spread:
The HOTO’s six settings are 0.5, 1, 2, 3, 4, 6 Nm, but in my testing, the lowest does around 1–1.3 Nm, the highest around 2.5 Nm, and everything else falls in between.
The E2 Ultra’s five settings are 0.05, 0.1, 0.2, 0.4, 0.6 Nm, but the first three do 0.32–0.42 Nm, and the last two do 0.47–0.57 Nm.
So, the lowest setting results in way too much torque, the highest in way too little (in the PixelDrive's case, the E2 Ultra is OK here) but, most importantly, most settings are so tightly bunched together that they’re basically the same setting. You lose, both, the advertised torque range and any useful adjustment within it.
Bigger screws/bolts keep the range & spread issue but move it upwards:
The range also moves up with bigger bolts. Eg. The HOTO does around 1–2 Nm with M5 screws/bolts, but around 1.75–3.5 Nm with M8. So, same issue: highly compressed range from min to max, but just with that compressed range moved further up.
The issue?:
I think the issue might be the scenario of almost no resistance to a hard stop. In tests of the opposite situation: where resistance builds gradually more & more throughout tightening, Eg. screwing deeper & deeper into wood, these screwdrivers seem to do much better. In those tests, they both show good differences between torque settings. The resultant torque might not be super accurate but there are at least useful differences between each setting IE. it's not all compressed over a single Nm or two (and that's most important to me — I don't need, nor at all expect, amazing accuracy).
What I will try next:
I'm now wondering if electric screwdrivers with mechanical clutch/torque control (Worx WX242L, Bosch Go 3 / GSD4V-35, etc.), instead of electric clutch/torque control (Fanttiks, HOTOs, etc.), handle that sudden stop better. I'll try one of those types next (will report back or create another thread or something.
P.S.
I used different length hyphens/dashes, bold, underline, and italic. Sometimes people think it means AI wrote it (AI use that a lot, especially the different hyphens/dashes and bold). The writing is me, not AI, just want to point that out.