I replaced my drill bits.
For frequent use on specific jobs,
I keep cobalt high-speed steel drill bits separate
（the ones I use most are 2.8mm, 4.8mm, and 7mm）,
but for other sizes I use a set from Nachi (NACHI).
It's less than 2,000 yen, but for the price, they cut really well.
The three smallest bits aren't lost—
they either broke or dulled, so I tossed them.
With stuff like this, it's better to
replace everything at once with new ones rather than keep patching up dull ones.
There's something really nice about brand new tools and blades.
Cobalt high-speed steel drill bits are generally gold-colored on the surface, but
some drill bits have a coating treatment applied to "make them look sharper by making them gold-colored".
It's nice that this drill doesn't use such tricks.
There are drill bits out there with titanium coating and other treatments
（which generally make the surface gold-colored）
that claim improved durability and cutting performance,
but they don't actually cut noticeably better than they claim.
With new ones, you might barely notice a difference, if anything.
They're definitely nowhere near as sharp as cobalt high-speed steel drill bits despite the similar appearance.
By the way, even with these new blades,
it's basically impossible to drill clean small holes through stainless steel screws, so
for that "S☆B wagon roller" from the other day,
I bought a separate cobalt high-speed steel drill bit
that costs more per bit than this entire 13-piece set.
When I tighten the double nuts,
I make sure the hex faces of the two nuts line up perfectly.
（That said, I'm buying a small bag of special 0.75mm pitch M6 nuts just for this,
so I should be able to find one with matching phase pretty much for sure.
Also, because the pitch is finer, it's probably easier to adjust the phase for tightening
compared to 1.0mm pitch nuts）
For frequent use on specific jobs,
I keep cobalt high-speed steel drill bits separate
（the ones I use most are 2.8mm, 4.8mm, and 7mm）,
but for other sizes I use a set from Nachi (NACHI).
It's less than 2,000 yen, but for the price, they cut really well.
The three smallest bits aren't lost—
they either broke or dulled, so I tossed them.
With stuff like this, it's better to
replace everything at once with new ones rather than keep patching up dull ones.
There's something really nice about brand new tools and blades.
Cobalt high-speed steel drill bits are generally gold-colored on the surface, but
some drill bits have a coating treatment applied to "make them look sharper by making them gold-colored".
It's nice that this drill doesn't use such tricks.
There are drill bits out there with titanium coating and other treatments
（which generally make the surface gold-colored）
that claim improved durability and cutting performance,
but they don't actually cut noticeably better than they claim.
With new ones, you might barely notice a difference, if anything.
They're definitely nowhere near as sharp as cobalt high-speed steel drill bits despite the similar appearance.
By the way, even with these new blades,
it's basically impossible to drill clean small holes through stainless steel screws, so
for that "S☆B wagon roller" from the other day,
I bought a separate cobalt high-speed steel drill bit
that costs more per bit than this entire 13-piece set.
When I tighten the double nuts,
I make sure the hex faces of the two nuts line up perfectly.
（That said, I'm buying a small bag of special 0.75mm pitch M6 nuts just for this,
so I should be able to find one with matching phase pretty much for sure.
Also, because the pitch is finer, it's probably easier to adjust the phase for tightening
compared to 1.0mm pitch nuts）