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Black Chromate, or "Why the special screws?"
At !!!MANIC Salamander, we're playing for keeps. We
don't want to sell anything that won't look and work at least
respectably after 10 years parked in the rain, washed twice a year,
ridden hard, etc.
We know we can't meet this ideal on every product in every way.
Sometimes it is technologically impossible. Sometimes it would cost
more than anyone would pay.
But here's one thing we can give you: GREAT
We use Grade 12.9 alloy Steel, Black Zinc Chromate-plated,
lacquered screws EXCLUSIVELY. They aren't sold commercially in
metric sizes, as far as I know, so I pay for my own batches to be
Why not just use 18-8 Stainless like everybody
It seems that all the aftermarket people are gravitating to 18-8
Stainless fasteners. There are a couple advantages:
- They don't corrode. Even when hot. That makes them a really
good choice for exhaust systems.
- They work ok.
- They look ok.
- They are available off-the-shelf.
BUT, let me tell you what I have found after 9 years
machine-building and engineering experience with both Alloy and
- Stainless fasteners get stuck and break off if anything goes
That means that if the threads of the screw are damaged or
contaminated with dirt, metal chips, rust or whatever, the
stainless screws have a tendency to get deformed by the mating
part, then to harden, and cut into the mating part, anchoring
itself so firmly, that within ¼ turn, it will freeze solid, and
- Stainless' strength to size, and strength to weight, are much
worse than Alloy Steel 12.9.
Maybe you keep your bike really clean. Maybe you keep your
threads really clean. Fine. Good for you.
But I do not. How can you if you insist on riding on miles and
miles of whatever you find, in wet weather? Back at the conveyor
belt company, it was pretty easy to fix a galled Stainless
fastener. All you need to do is break it off with a wrench, grind
it nearly flush with an angle grinder, weld it in with a TIG welder
and some filler rod, grind it flush, redrill, and re-tap the
threads. Easy as pie. But I don't carry that kind of equipment when
I tour, and I want my fasteners to behave themselves anyway.
Grade 12.9 Alloy Steel is tough as nails. No, scratch
that. Nails are nothing. It's dozens of times tougher than
- The threads can be abraded and damaged, but it is much harder
to do. Dirty or deformed mating parts won't make your screw
useless. It is still worth correcting, but if you're careful, the
screw can tough it out.
- Even if the screw threads get damaged, they stay smoother,
allowing the screw to still serve its purpose in far worse
condition than would be safe with Stainless. A Grade 12.9 Alloy
steel screw will probably be with you at the end of a muddy
round-the-world trip, unless you do VERY, VERY bad things to
- The threads are much more precise and smooth, making for a real
- It has phenomenal tensile strength, more than I'll ever ask of
One problem; it rusts.
That's where the Black Zinc Chromate and lacquer come
I asked around, and this is about as good as it gets. My vendor
tells me they coat fasteners this way for Honda. This is almost the
same coating as the Green Zinc Chromate that the military has used
They have a dull grey-black speckled appearance. You may have
seen some like them on your bike from the factory.
If you leave your bike in the weather, ride it in the salt, and
wash it twice a year, these fasteners probably won't start to rust
for 10 years. The only place I wouldn't use them on the chassis is
on the exhaust pipes. It is too hot for the coating.
It's a big bother, and it costs money. But as a professional
machine builder, I know they are worth it. It is one more battle
won in the fight for a quality product.