What's special about them? They look like every other cheap set of bits, except not cheap
I came up with a better answer than I provided previously.
Wadsworth K47P
Consider first the fancy Wadsworth K47P Super Deluxe Set 52pc screwdriver bits. I own this set and it is most definitely not meant for firearms, but, it does better than most in providing a decent list of slotted screwdriver bits. Specifically, SL0, SL1, SL2, SL3, SL4, SL5, SL8, SL10, SL 3/8. No comment on widths, probably (did not verify) standard widths when applicable. There is a good variety of widths. There are numbers other bits that I will not focus on, but specifically, HEX metric and SAE, Phillips, and Torx bits.
Ignoring that Wadsworth bits will only work with Wadsworth drivers, they do not label the bits. This is annoying. The driver is very high strength, not what I usually want when working on firearms.
Chapman
I own the Chapman #1000 Mity Master Set (the biggest set) along with some extra bits, mostly the bits meant for firearms. They also have a set specifically designed for firearms. The bits are all well labeled but the markings provide no helpful information in understanding the dimensions of the bits; for example, the #17 is 1/4" x 0.037". The firearm specific set has nex and star bits as well as slotted.
Here are some of the Slotted bits measured in inches (left) and metric (right). This is the only set that labels any of the bits with metric measurements.
Inches | Metric |
0.125/0.023 | 3.0/0.5 |
0.160/0.030 | 3.5/0.6 |
0.190/0.025 | 4.0/0.6 |
0.190/0.030 | 4.0/0.8 |
0.190/0.037 | 5.0/0.8 |
0.230/0.037 | 5.6/1.0 |
0.250/0.025 | 6.5/1.2 |
0.250/0.037 | |
0.328/0.030 | |
0.328/0.037 | |
0.328/0.050 | |
0.375/0.025 | |
0.375/0.037 | |
0.375/0.050 | |
Brownell's
Now take a look at what Brownell's includes in their set, well, mostly anyway. This is the layout as provided by Brownell's. Anything in rows 7 and 8 are not included in the set but available as an extra, but there is not an easy place to put them in the included box. I did not list all available bits, I think that there are more.
For each width there are multiple thicknesses so that you can find a best fit bit as needed. The 0.120" width is very close to 3 mm, but not a large selection for metric. And as already mentioned previously, these bits are made by Zephyr and the insert bits contain Zephyr labeling.
| #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | #11 | #12 | #13 | #14 |
1 | 0.360/0.070 | 0.340/0.070 | H 5/32 | H 3/16 | H 7/32 | H 1/4 | | | | | | | | |
2 | 0.360/0.060 | 0.340/0.060 | 0.300/0.060 | 0.270/0.060 | 0.240/0.050 | 0.210/0.050 | | | | | | | | |
3 | 0.360/0.050 | 0.340/0.050 | 0.300/0.050 | 0.270/0.050 | 0.240/0.045 | 0.210/0.045 | 0.180/0.045 | 0.150/0.045 | 0.120/0.045 | | | | | |
4 | 0.360/0.040 | 0.340/0.040 | 0.300/0.040 | 0.270/0.040 | 0.240/0.040 | 0.210/0.040 | 0.180/0.040 | 0.150/0.040 | 0.120/0.040 | | | | | |
5 | 0.360/0.035 | 0.340/0.350 | 0.300/0.035 | 0.270/0.350 | 0.240/0.350 | 0.210/0.350 | 0.180/0.350 | 0.150/0.035 | 0.120/0.035 | H 9/64 | H 1/8 | H 7/64 | R2 | PH1 |
6 | 0.360/0.030 | 0.340/0.300 | 0.300/0.300 | 0.270/0.030 | 0.240/0.030 | 0.210/0.030 | 0.180/0.030 | 0.150/0.030 | 0.120/0.030 | H 3/32 | H 5/64 | H 1/16 | PH0 | PH2 |
7 | | | | | | | 0.180/0.025 | 0.150/0.025 | 0.120/0.025 | | | | | |
8 | | | | | | | 0.180/0.020 | 0.150/0.020 | 0.120/0.020 | | | | | |