Can you indicate what thread and head type. I know that doesn't answer your question but it may help to locate some screws. (It also helps to push your query back to the top of the list!)

Brian

Plenty of fixing suppliers. I use Spalding Fasteners and Bolt Base, they both have a usually quick turnaround.

Andrew.

I have had good service from

GWR Fasteners Limited

Jude Robinson

Units 6-7 Artillery Business Park

Garrison Avenue, Park Hall,

Oswestry

Shropshire

SY11 4AD

United Kingdom

Phone:01691654979

Email:[email protected]

They have an e-bay shop. Good, fast, service. I’ve used them several times.

A couple of points regarding the use of stailless steel and aluminium if I may.

There is a theoretical risk of corrosion occurring due to the reaction caused when using dissimilar metals. This is easily solved by applying Copper seal to the threads.

No doubt you have all seen those large glazed facades on offices, shops and shopping malls, plus all of those glazed roofs roofs on many commercial buildings. Well, as somebody who was involved in manufacturing and installing many such projects, I can tell you that without exception the corner joints, fixings and component fasteners are just about 99% stainless steel screwed into the aluminium extrusions which themselves have screw ports extruded into the profiles. I am not aware of any such assemblies failing due to the mix of stainless and aluminium.

Remember also that many boats are aluminium hulled and their fasteners and even the topside fittings are very commonly also stainless steel. Again I know of no failures due to this.

I use stainless steel fasteners on all exposed areas of my restored motorbikes and into the aluminium engine casings and once again no failures in almost 60 years. I hope this helps in this debate.

I've had plated bolts into cast ali on motorbikes where the (zinc/ali?) plating has rusted out causing threads to collapse when removing bolts. Chinese A2 stainless bolts are normally sold degreased and using them out of the packet causes problems. I use CopperEase grease on new stainless bolts and haven't seen corrosion or thread damage yet.

Stainless-steel and aluminium-alloy can be a bad combination depending on the individual grades and the environmental conditions.

The alloys for marine use should be ones developed for the role. I have seen an assembly that had spent some time in the sea, in its intended use, whose stainless-steel thread inserts sat all smug and bright in craters filled with white sludge, in the aluminium end-plates.

I can't see it being a problem in something that is drenched in oil; but it certainly can be with any water about.

A non-metallic grease – mineral, silicone or petroleum-jelly – may be better than a copper-based anti-sieze compound.

I used to test experimental assemblies made typically from "ordinary" aluminium-alloy (HE30 – I don't know its modern moniker) held together with A2 or A4 grade stainless fastenings. Despite their designers' touching faith in anodising, the test-pieces' necessary immersion in a tank of fresh water kept sweet with only normal swimming-pool filters and additives soon started things fizzing.

I wonder if this could also be a problem for miniature railways using stainless-steel bolts with aluminium rails. It might not if the joints are always above the ballast and kept clean, but may be if vegetation or soil accumulates around the track.