Bakelite Brembo pistons

  • Thread starter Thread starter bob
  • Start date Start date
thats what I call bakelite (from my collection) :D

Shaun
 

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Large Neale :D :D

Ekco AD65 1934 designer Wells Coates The first and rarest round Ekco.
Sad aint I?
 
Breganze-Engineering said:
Paul: yes A4 is the High Tensile grade, almost the same shear strength as HT MS.

Veravista: Yes, all grades of SS have a degree of magnetism but its often so low as to be difficult for the layman to detect......

John B: not nesscarily....

Note: I don't pretend to be an expert on SS, I am but a humble Gunmaker who works with it every day in my workshop, but my Dad is.....

Ross.
Click to expand...

Thanks Ross.
I'd always gone by the presumption that A4 was for damper applications, marine for example. I was always told that the more resistant to rusting, the more brittle.
In the future, I'll therefore use A4 in brake applications, caliper and disc mounting for example.

Ciao
Paul
 
Paul,

Be careful with using A2/A4 stainless in applications where there is constant heating and cooling. These stainless grades do NOT take too kindly to constant cyclic loading and snap like a carrot in such cases.
How do I know this? Well I worked in Pharmaceuticals for 10 years, stainless stuff everywhere!
These fasteners are fine for chemicals, solvents, acids etc etc. But snap when used on steam/condensate pipework.
The problem is the constant heating and cooling(expansion and contraction)of the flanges as steam/condensate is regulated. This loads and unloads the bolts and snaps them.
High tensile carbon steel = no problem (grade 8.8 Mpa).

Mind you I am not too paranoid, there are some A2/A4 fasteners on my bike. I am just a bit picky where I put them.
 
Ive got A2 grade bolts on the caliper halves, caliper mounts, engine bolts, stanchion clamps, side casings, clip-on clamps, cam cover etc on the 500 for over 25 years now & have had no problems whatsoever....
 
Breganze-Engineering said:
Ive got A2 grade bolts on the caliper halves, caliper mounts, engine bolts, stanchion clamps, side casings, clip-on clamps, cam cover etc on the 500 for over 25 years now & have had no problems whatsoever....
Click to expand...

Yes, same here. Discs bolted to carriers with A2 on the SF2 twenty years ago and that bike has seen some hard braking 2 up.
Paul
 
I think you were right the first time Paul, these grades are more brittle than high-tensile carbon steel, Please read this:

Link: http://www.volksbolts.com/faq/basics.htm


'What's the difference between A2 and A4 Stainless Steels ?

  A4 grades of stainless steel are usually reserved for use in highly caustic environments where improved resistance to pitting corrosion is required, i.e Marine & exhausts.
Pitting corrosion occures once the chromium becomes exhausted through self-passivation after caustic attack - the effects as usually local to the exposed areas. The pitting forms as the Iron atoms become exposed to Oxygen and form 'rust'.

The improved resistance comes from the addition of a higher proportion of Chromium, which helps to form a protective oxide layer on the iron - the more chromium you have the longer the protection it offers lasts.

However, whilst some properties are improved, others deteriorate. The extra Chromium makes the metal more succeptable to fatigue and cracking : OK if your rolling serenly around on the high seas : not so OK if you driving a rickety old banger like a VW.! '


 
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