Where can I find a thin wall M5 (8mm) box spanner?

[TheOrs]

If it's stainless in alloy, use lots of copper grease at least!

Are you suggesting this to prevent corrosion due to the two dissimilar metals? My understanding is that copper & aluminium is not really a good combination in a marine environment as copper is significantly more noble; similar to stainless in it's position in the galvanic series.

We usually use molybdenum disulphide grease on stainless but I am not sure how this sits with aluminium. (makes note to self to check on this tomorrow).

 

[reeac]

Strange googling box spanner gave loads of hits
http://www.screwfix.com/p/box-spanner-set-8pcs/4883f
£10 for a complete set

I agree. I definitely had problems finding any about 15 years ago but now they've reappeared. Maybe during the loadsamoney years they were seen as too cheap but now times are hard they've been reinstated. I needed one to tighten deeply recessed nuts in the rafters of a roof of a garden room that I was building.

 

[lw395]

Are you suggesting this to prevent corrosion due to the two dissimilar metals? My understanding is that copper & aluminium is not really a good combination in a marine environment as copper is significantly more noble; similar to stainless in it's position in the galvanic series.

We usually use molybdenum disulphide grease on stainless but I am not sure how this sits with aluminium. (makes note to self to check on this tomorrow).

There are better things than copper grease, but it seems to do the job.
I've used it OK for many years on bikes, having discovered that stainless bolts were much more likely to seize in alloy than plated steel bolts, when I had my first bike.
I don't know what the metal is in the silver coloured alternatives like Nevr Seize etc?
I have a big tube of something like that with an obscure part number, I dispense it from a little syringe.

Not sure why the nobility of the copper doesn't cause more problems than it solves as you say, but it does seem to work better than ordinary grease?

 

[NPMR]

How does the head style of the bolt affect its corrosion characteristics?

Possibly my explanation was badly written?

The original stainless captive bolt, with Allen key head was set into a cast aluminium body, which with sea water set up massive corrosion that the Allen slot/key hole was simply not man-enough to withstand the twisting needed when I tried to undo it. So I had to drill out the s/s bolt and then lever the burred head 'through' the casing to finally separate the two sides.

I originally wanted to repair by fitting simple nuts/bolts but kept from touching the aluminium with nylon cap washers both sides but that needed the hole to be drilled out a good bit larger but there was insufficient metal to do this.

My compromise has been to drill the holes a bit bigger, cover the bolts in thick layer of PTFE tape, with nylon washers under bolt head and nut (and Duralac everywhere) but the nut is in the original hole. So very, and I mean really close to the aluminium wall which is now re-powder-coated so I'm keen to minimise damage to the paint.

Off suggestions here, I have a thin walled box spanner on way. Hope it's thin enough. Brilliant suggestions though. Is this site good, or what!!?