Machining Naval Brass?

[Halfnuts]

I recently inherited a Rockwell 10" 36" between centers lathe and 21-100 mill from a dear friend. My friend was an industrial model maker and did a lot of work in brass and aluminum.

With the rest of the shop were several lengths of 2" marine propeller shafts. My friend told me several years ago that he tried machining them, but they were naval brass and were too hard to machine. I wonder if anyone can tell me precisely what the problem is. Is it worth keeping the material, or should I sell it to the metal recycler?

 

[CluelessNewB]

I made a saluting cannon with some recycled marine shafting. It's not as easy to turn as free-machining leaded brass or aluminum but it's easier than most steel. If a file cuts it you should have no problem. Tooling might require a different grind (less rake).

 

[mikey]

I bet that stuff is Manganese Bronze. I would use carbide insert tooling and would definitely keep it.

 

[Briney Eye]

I recently inherited a Rockwell 10" 36" between centers lathe and 21-100 mill from a dear friend. My friend was an industrial model maker and did a lot of work in brass and aluminum.

With the rest of the shop were several lengths of 2" marine propeller shafts. My friend told me several years ago that he tried machining them, but they were naval brass and were too hard to machine. I wonder if anyone can tell me precisely what the problem is. Is it worth keeping the material, or should I sell it to the metal recycler?

First, try sharp HSS tooling with zero back and side rake, and experiment with the side rake, which might even need to be negative.

 

[middle.road]

2" DIA.?!! Now that's a score for sure. Hammers anyone?
'Navel Brass' IMO is a generic term.
As mentioned above, it's probably been alloyed to handle the stresses of being use for a drive shaft.
Carbide will handle it.

 

[Ulma Doctor]

Aluminum Bronze is used in maritime parts
it is a very tough material

if you have the right tool, any material can be cut
start with cobalt HSS and move up to carbide if necessary

if you don't want the material, i do!!!!
i can trade or pay for it
ulmadoc@gmail.com

 

[Halfnuts]

Ok, thanks, guys. I want to give it a try before getting rid of it. My friend made a series of scale naval and Civil War canons from 360 brass. He told me when he tried to turn a piece of the naval brass he concluded that it wasn't machinable, and he set it aside. I never knew him to machine anything from steel, so I expect "unmachinable" was a relative term.

I'll consult Machinery's Handbook and play around with different grinds on HSS first. I have carbide, too. And, yes, I always thought marine propellers and shafting were made from manganese bronze. So maybe that's what it actually is. He called it Naval brass, though.

Thanks!

 

[Halfnuts]

I made a saluting cannon with some recycled marine shafting. It's not as easy to turn as free-machining leaded brass or aluminum but it's easier than most steel. If a file cuts it you should have no problem. Tooling might require a different grind (less rake).

Yeah, one of the things my friend made was a saluting canon for his yacht club. It was intended to be used for starting races off the committee boat. Trouble was, it used 10ga shotgun blanks, and the barrel was a 2.5" inside diameter tube of 360 brass 18" long, 3/8" wall thickness. The thing was so loud, people complained. So they went back to using an old 12 ga. shotgun to start races, and the starting canon, made from polished brass with a beautifully machined 316 SS breech, now resides in a trophy case.