Sacrifice

Not quite sacrificial but white metal bearing linings are used for two reasons, firstly they melt without damaging the shaft if they lose the oil supply, secondly large abrasive particulate in the oil embeds deeply enough *not* to make it become a lap.

Tip: this does not apply to bronze bushes running (lubricated) on hardened steel shafts. A colleague once thought it might be a good idea to polish some car internals with (snaffled) diamond paste. Evidently he did not clean it sufficiently well, because there was enough in the system to turn the bronze camshaft bushes into laps, which wore out the camshaft bearing sites in a few thousand miles.

Happens a lot on the internet

Too late, I'm afraid. For the purposes of this thread, "sacrificial" now means something entirely different, and *that* is what the vast bulk of posts and posters will be addressing.

Happens a lot on the internet.

Rubber marbles, now there is a concept. Brian

I walked on a not very old lava flow once, I found out why everyone else wore clogs. Brian

That would be virtual sacrifices. I like to keep old things going hence me using Outlook Express Google eternally moan about it, but their replacement is about as user friendly as a porcupine. Brian

Your money, when Mrs is shopping in the sales :-)

Andrew

In that case, all that infernal single-use plastic film that seems to surround almost everything these days, to 'protect it'.

Yes but, the problem with 78s was that they were by nature abrasive. Thus they used steel needles which only wore out, but also did damage the grooves as they did so due to the poor compliance in an acoustic diagram and horn system. You are moving a lot of air with a small area. It was only with the advent of electronic amplification that you could allow the compliance to drop low enough to let you use softer plastics to made the record. Some very late 78s, notably those by The Beatles issued in India were made of something like Vinyl. Brian

I think I got my words mixed up, but I'm sure you got the gist of that, its been a long day. Brian

Actually the needles were in fact made from a fibre or fiber as they say in the states and were particularly useless on Shellac. Brian

Oh dear, as bad as that eh? When you etch a pcb, how do you get the copper back out of the ferric chloride? Brian

Yes most chief executive officers seem to be sacrificial. How often have you heard that the ceo fell on his sword, as he had ultimate responsibility. Brian

Yes like the heat shield on the Apollo capsule, which ablated to take the heat of re entry away. It gets more blurred when you look at the candle. Some candles burn the impregnated wicks and the melting of the wax is sacrificial as its only purpose is to hold the wick atop the rest of the wick, so has to melt to achieve this. However I came across some candles where the actual wax as it melts releases a substance that makes the candle aromatic. Brian

I think most of my examples are sacrificial though.

Brian

So what are oilite bearings made from, whatever it is its fine for some time then starts to chatter. Brian

Nah! The wax is what burns.

Bill

Most seem to bail out using their golden parachutes.

They are described as sintered bronze. I have sometimes wondered if they are just mechanically compressed bronze powder, and not actually cooked at high temperature to induce diffusion bonding, although I could be wrong. This would need to be done in an inert atmosphere.

They hold oil in the pores for quite some time and don't need a flowing supply. But they do dry out eventually and need topping up. There are commercial variants that contain graphite, these have very good performance.

Replaceable dropout derailleur hanger for aluminium frame bike.