Thread: Stainless Steel Bolt replacements for Defender 110 ?!?!

Originally Posted by gromit

John,

I remember a lot of problems back in the UK in my motorbike days. Stainless bolts holding thin aluminium mudguards in combination with the rock salt they used on the roads in winter and the aluminium corroded badly. Change back to galvanised or cad plated bolts and problem went away. Less of an issue here unless you are beach driving.

Galvanic Series Relationships are shown here (tested in seawater)
Galvanic series


Colin

I sell a lot of tooling to motor cycle restorers. Particularly taps and dies in BSC, CEI Coarse, and UN 24 pitch series. Many restorers like to have stainless fasteners as they dont rust when the machine is stored in the shed for months or years without use. I always stress to a new customer not to replace heat treated high tensile fasteners with stainless. I also give them a handout on hand tapping stainless. If you are ever going to break a tap, you will do so in stainless if not very careful. Thus you may have a broken tap in the only Bradford Bunfight crankshaft in the world. This can seriously ruin your day.

There is a guy in Brisbane who caters to the hobby by machining special parts and fasteners. He tells his clients to bring their own taps and dies if they want him to make stainless fasteners. He doesn't want his own flogged out or broken. Stainless is hard on thread cutting tools.

"Stainless Steel" is actually a cutlery steel patented in 1916 and the term has come into common use for all of this type of alloy steel. The correct and long winded term is Chromium Nickel Corrosion Resistant Alloy Steel.

There are a multitude of grades. All contain chromium, some contain nickel; some are magnetic, some are not; some are martensitic, some are austenitic; some can be heat treated, most can not.

IMHO, Cad plated screws and bolts are best -the closest on the galvanic corrosion table to neutral for both aluminium and mild steel that many of the screws end up joining together... BUT cad plated bolts and screws are hard to come by as cadmium is poisonous and only really used in aluminium airframes... which (again IMHO), are probably closer to a series/110/defender style landrover in build materials and form than any other vehicle going about ;-)