Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Engineering Techniques and Materials. => Topic started by: treeboa on November 21, 2011, 01:09:12 pm

Title: hard brass ??
Post by: treeboa on November 21, 2011, 01:09:12 pm

quick one, picked up some brass from the local scrappy, one bit, a nice useful 9 inches *3/4 is an absolute pig to cut on the lathe, its not my tools as they are cutting other brass and steel, this stuff had a look of black iron on it when i picked it up, but i was assured it was brass, looking at the machined ends yes it was brass coloured, gets it home, chucks it up to run a cleaning cut over it and it struggles with a couple of thou cuts !!, does not sound right either,  the other brass i got at the same time is like butter and cuts well even using the same tool this ` brass ` is refusing to take a small cut from

any ideas  :-))

Title: Re: hard brass ??
Post by: Subculture on November 21, 2011, 02:26:35 pm

Silicone bronze perhaps? That's pretty tough stuff, looks like brass, but works a lot differently.

Title: Re: hard brass ??
Post by: treeboa on November 21, 2011, 02:51:14 pm

cheers - my vario lux does not like the stuff thats for sure  :embarrassed:, is there any way to soften the stuff ??

Title: Re: hard brass ??
Post by: HS93 (RIP) on November 21, 2011, 03:19:15 pm

 I had the same Problem recently some 40mm rod looked great till I started turning it and as it was a new lath I thought , I hoped it would be better than this then I noticed it was more of a gold colour. tried some stuff i knew was brass and no probs.

Peter

Title: Re: hard brass ??
Post by: TailUK on November 21, 2011, 05:08:53 pm

I may be teaching my granny to suck eggs here but check your tool angles.  Bronze should use the same angles as a tool ground for brass but brass will turn with a tool ground for mild steel.  So if you've got a mild steel ground tool the bronze will give you trouble.  I found this table which I find very useful.
(http://s12.postimage.org/qpa4h4c49/angletable.jpg) (http://postimage.org/image/qpa4h4c49/)

Title: Re: hard brass ??
Post by: boatmadman on November 21, 2011, 05:25:27 pm

Try cutting a bit off, heat to cherry red and quench in cold water, then try re machining it. If it softens its brass, if not it maybe phosphor bronze, which, if your tooling isnt correct as said above, will be a pig to cut.

Ian

Title: Re: hard brass ??
Post by: Circlip on November 21, 2011, 05:31:21 pm

Is it a light yellow and slightly magnetic? If so, it's Aluminininium Bronze and tougher than a witches mammery. Sharp tool, plenty of coolant, DON'T let the tool rub.

   Regards   Ian.

Title: Re: hard brass ??
Post by: treeboa on November 21, 2011, 05:50:47 pm

not magnetic at all, however unlike the dull tone when struck with a piece of steel like the other bits of brass i have here,  this sounds almost bell like when struck

Title: Re: hard brass ??
Post by: HS93 (RIP) on November 21, 2011, 07:27:43 pm

yes I took some to Boggys and he reckoned it was Aluminininium Bronze from an aerospace suppier ( I think it followed him home). it turned ok with a profile tool but it was a bit more effort than I thought brass would be.

Peter