I ordered from Accu Fasteners what to them would be a very small quantity of some particular sizes of fittings, from their stocks, including Spring Washers (similar to Belleville Washers but thinner gauge – they stock those too).
Placed the order yesterday (I think – might have been Tuesday), their padded envelope plonked through the letter-box this morning.
The fasteners included Disc Springs, similar to Belleville Washers but thinner gauge – they stock those too – and Cap Nuts, also new to me. Think of Acorn Nuts with the hexagon section almost full height to a rounded top.
Disc springs and belleville washers are for constructing stacked springs to give an even but low loading, and mine are for that purpose on a disc-type vacuum-brake valve.
Neither these nor the cap nuts appear in the usual model-engineering suppliers’ books.
Two more orders to come… Spalding Fasteners selling me two rolls of small-diameter copper tube; and a sizeable shopping list to Blackgates.
Only, the latter are out of the copper shim washers I wanted, and tell me they seem to be no longer made. I don’t know if other suppliers are affected but it could mean considering alternatives including making our own from sheet material.
I was rather surprised to find each pack from Accu came with a Certificate of Conformity, informing me the weight of the disc springs is a hefty 0.0012kg. I am not sure if that is per spring or for the 10 I bought! It’s all right – I remember what I was taught at work about manual handling.