I forgot to buy soft copper washers and so ended up Making Soft Copper Washers. |I know, this feels a bit extreme, but I really wanted them now so that I can run a proper steam test on my small vertical boiler.
A strip of copper is drilled slightly undersize. This means I can finish the hole of with a hand reamer.
Hand reaming the holes to size just means that the hole in the centre is closer to a perfect circle.
Now I have 7 roughed out copper washers.
At this point I then flatten them with a pair of parallel pliers. However, when you bolt them onto the mandrel they will get flattened.
You can trim the corners as this will reduce the likelihood of them catching on the lathe tool during the initial cuts.
A simple mandrel with a section machined down in diameter to match the centre hole of the washer. All of the roughed out washers loaded onto the mandrel, note steel washer each end to support them. Initial machining of the washers to size. Take small cuts as this is when they can catch and then rotate. The stack of washers all machined to the correct diameter.
Once the washers have been machined to the correct diameter they can be removed from the mandrel.
They then need deburring. You can file the edges or just run a knife around the edges, either is fine.
I would avoid sanding the surface as they have originally been cut from a flat sheet of copper. Thus they will naturally be a consistent thickness.
Finally I anneal the copper washers.
This is quite easy, heat them up to a dull red and then dump them into cold water.
You might just have to brush some flakes of oxide off, but otherwise that is it for making soft copper washers.