Help distinguishing bronze materials

easy way a lightly equipped tyro can tell which of

roundness can not be checked with a micrometer. Why not,

Taking up the roundness issue - if you measure the diameter of a 50p or 20p coin at any point it will be the same though looking at it it is obviously not round. Steel that has been ground on a centreless grinder similarly can be lobbed but will read correctly with a micrometer.

I'll leave the bush issue to others !

AWEM

I assume you don't have a friend with access either to a scanning electron microscope with analysis kit or a metallurgy lab. (I'm not being flippant, it's the sort of job I used to do an a spare 5 minutes when I had access to such kit). You can also make a reasonable guess from a hardness measurement; you might find a suitable machine in a small engineering works or any undergraduate metallurgy lab). Assuming it is from an old component, your difficulty is going to be finding a direct equivalent because the old British Standard bronzes have been superceded. That said, you will probably get away with it if the Vickers hardness is within plus or minus 10 points. Tell us more about the application (for example if it is marine it might need better corrosion resistance).

Ah, another EDAX (or EDXA) man. They seem to have become a popular hobby over the pond. I gather you can pick up a complete kit for around US$5K. Liquid nitrogen must be a bit of a drain on the pension though.

Ken.

I always use a DTI to sort the twenties from the pennies.

Ken.

"Newshound" wrote > Tell us more about the application

It's one of a pair of bushes which the spindle of a Raglan 5 inch lathe runs in.

I carefully followed the manual when stripping the headstock to replace the bearings. Result: one wrecked bush with a wooduff key slot from a woodruff key that shifted out of it's normal position parallel with the bore of the spindle. :-(

Phosphor bronze is used for some other components and the bush has marked the spindle a bit, so my guess is it's P-B, and I'm was hoping some of the more erudite here could either confirm or deny this.

Many thanks to those who replied on the roundness question.

Regards, Arthur G.

Arthur,

Strangely enough, I've been discussing the various types of PB and leaded bronzes with a colleague in connection with his traction engine recently. From what I read about the subject, PB1 would be the most likely material for this problem, as it's well suited to relatively high loads, and performs best when the shaft is highly finished as well.

Hope this helps

Alastair

I thought in bulk it was about the same price as milk. Perhaps I mean beer.

I'd agree with this, I think I would go with a plain (not leaded) phosphor bronze for a lathe spindle. Does it have a "cup" lubricator? I think you would want a modest oil supply.