Generic brake pad tuning

I was thinking of tuning options for my Ruegamer dual pivot brakes. There aren't many options for the brake pad holders. The three which I like the most being:

xx-light-bikes.de, Zero Gravity brake pad holders, 29g

BTP brake pad holders, 25g without pads; 44g with SwissStop yellow pads (+19g)

32g with Corima cork pads (+7g)

Then, I had an idea. The brake pad holders themselves weigh hardly a tad. So no matter the % difference in weight between different materials, the absolute weight wouldn't vary much.

And I happen to have a set of generic brake pad holders that weigh a total of 68.6g.

So... I took a magnet near them to investigate. No attraction, it felt. But it was too heavy to be aluminium by my judgment, so it must have been an austenitic grade of stainless steel - likely the common type 304 i.e. grade 18-8 stainless steel which I'm using for most of the parts on my particle accelerator. So I don't have to worry about rust if I were to sand them down.

Took one apart to get an idea of the distribution of mass:

Brake pad, ~20.0g for 4... A tad heavier than yellow SwissStop pads.

Steel pad mounting bolt (male)

Steel brake pad mounting bolt (female)

Steel spacers (top: inside, bottom: outside)

Steel pad stopper bolt

I'm missing a photo of the brake pad holder itself, which weighs 6.7g on its own. (~17.2g total for one brake pad). By estimation, I have a few tuning options:

1) Sanded brake pad holder
2) Cork pads
3) Nylon spacers
4) Aluminium stopper bolt
5) Aluminium mounting bolt (male)
6) Drilled slot on brake pad holder

I don't have an idea what the goal for the final weight is. Anywhere near the BTP w/ yellow SwissStop pads' 44g is nice. Meaning, I have to save 24.6g!

So, I proceeded with (1) first. I thought of dunking the whole pad holder into paint thinner first. But it didn't seem to have an effect. I can't explain why, to be frank. Anyway..., I might as well sand it all apart...

My first weapon of choice: half-rounded file; and makeshift workstation using disused XFX graphics card box to keep my floor clean.

Secondary weapon: 150 (not pictured), 220, 400, 600 grit sandpaper and water for wet sanding (not pictured)

I kind of regretted my choice of weaponry after a while. To be honest, I never sanded stainless steel by hand before... I think I won't be doing it ever again, after - as well. So I thought of equipping a hacksaw instead...

Second weapon of choice: small hacksaw.

Then I regretted it again... and decided to go back to the half-rounded file. I should use a dremel...

So... I ended up spending almost 1.5 hours sanding away with the flat surface. I spent another 30min or so just cleaning up as much of the remnants of the black coat in difficult corners with the half-rounded section.

And that's just one pad. (Then my sister pointed out that it was 2.30am and she needed to sleep - which she couldn't, hearing the sharp noises from the living room.)

Now it looks nice and chrome-ish. 1.5g savings per pad holder! To be continued... but that's -6.0g when I get all of them done. So I have, in theory, another 18.6g to remove. Changing to Corima pads would remove another 13.0g exactly... leaving me another 5.6g to solve, with options 3, 4, 5 and 6. Sounds very plausible.

It's difficult to reach the inside surface without the dremel, otherwise I could remove another 0.2g or so per pad! But even if I used the dremel, it's difficult to tune this part of the holder without causing structural uncertainties...

Shiny appearance after final round of wet sanding with 600 grit sandpaper. And my blackened fingertips, after taking a lot of damage.

Oh, and I ran out of 220 grit sandpaper. Got to buy some. ^^ I must take note not to overuse the sandpaper, otherwise the weight savings to cost ratio diminishes below getting a new set of BTP pads (129 euros excl shipping... uhhh...)!

To be continued...