Material suitability

In my metals box I have a few lengths of non ferrous copperish alloy bar. It's not Brass or PB, it takes a bit of drilling and the turnings when put in the lathe come off with a coppery silvery sheen. I believe they came from a company that made ships fittings in the past that I used to work for many years back. (Taken with the Bosses consent). Now without seeing I know it will take some identifying but perhaps some metallurgist out there may be able to suggest what it may be and advise on it's suitability for shaft bushes for the shafts in the cam grinder I'm making.

Thanks in advance for any info.

Graham W

Graham,

There's a good chance that it's this

MichaelG.

I think Manganese Bronze (the alloy, not the company that was once the British motorcycle industry) is used for marine applications such as propellers.

JA

This sounds like Alu. Bronze which I have used as bearing metal, it is much harder than normal bronze derivitives and is quite difficult to even ream unless they reamer is new and sharp. It is so hard that as a bearing materiel will wear away a steel shaft before it wears away. My materiel came from messed up Cryogenic valves that were test pieces from a CNC machine. They had to have several goes at it before they got the machining right. Tough old stuff.!

Clive

Thanks for that Guys, read the link that Michael posted and also looked up the Manganese derivative, can't say I'd heard of either before. Decided to make the bushes out of it and see how they go, don't think the application is to severe as to rotation speed, perhaps just dust. Turned the diameters and bore OK and set to with my hacksaw blade parting tool, locking everything tight. Tough going just as you say Clive, never had trouble parting Brass, Ally or even Steel but this required lube and a very slow input speed, very nervous going LoL.

Thanks again

Graham W

John. Your post came through just after I put my last post on. Got the pot magnet out and checked but it's not magnetic. So ???????

Graham

Could be Gun Metal.

Mike.

Hi, here is a piece of Ali-bronze. I don't know what grade it is, but it is a slice from a worn out nut that the turner at my old place where I used to work used to make for a palletizing machine, the big hole at the bottom R/H corner is where the grease nipple was screwed into. This piece has no magnetic attraction that can be detected with a permanet magnet.

I have just removed it from a special camera mount that I made many years ago, and have given it a quick rub up with some of that fine scotch type of stuff, but it will polish up to a very nice lustre, but will tarnish quite quickly. It is a nice metal, but has a kinda stickyness to it when drilled and will very quickly get hot and grab the drill bit to a stop if you try to drill to fast or heavy.

Regards Nick.

Edited By Nicholas Farr on 22/07/2014 19:58:03

Hi Graham W5 I agree it sounds like Ali bronze where I worked at onetime we were making a lot of seawater service fittings for the shipyard in Barrow.

Clive interesting about the bearings, I once used some Ali bronze to make crankcase bearings for a very ancient Atco 2 stroke lawn mower, it promptly seized up so too tight thought I and opened them up. This happened several times and I revered to phosphor bronze and that solved the problem. Another colleague use some to make a bush for his motorcycle gearbox, this seized and destroyed the outer case so we determined it was not a suitable material for bushes ?

Interested in anyone else's comments, personally I have not used it for shaft bushes since ( 40+ years)

P S makes excellent cannon barrels ! Looks just like brass but no polishing !

Edited By JohnF on 22/07/2014 21:50:42

Hi Nick. Picture looks about the same colouration as the bushes, though they haven't tarnished overnight. Drilling out was exactly as you describe. Got 14 bushes to make in total all around 7/16" long with bores of between 3/8" and 1/2", diameters 1/2" to 5/8".To avoid buying the PB that the drawing indicated I wanted to use what I had so will go with it and see how it performs. Also substituted bright EN8 for the advised Drill Rod. If they fail don't think it'll be as catastrophic as that that JohnF referring to if they do. As an aside has anyone on the forum made the Gene Switzer cam grinder? would like to see some pictures of one finished or a General Arrangement view as the drgs in Strictly IC are not that good. Did post on Home Machinist website but no replies.

Graham W

If I recall correctly, plain bearings require a specific aluminium/copper mix, so not all ally/bronze will be suitable for bearings. It's main benefit is corrosion resistance.