Brass v.s. Bronze?

Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.

Moderators: Harold_V, websterz, GlennW

User avatar
DianneB
Posts: 575
Joined: Tue Aug 21, 2012 3:05 pm
Location: Manitoba, Canada

Brass v.s. Bronze?

Post by DianneB » Tue Dec 12, 2017 11:22 am

I am preparing to build a VanBrocklin pump from Bill S. plans.

I have a large piece of bronze surplus to my needs but no brass.

Is there any reason to buy brass or can bronze be substituted in making the brass parts?

(I have very little experience machining small parts!)

Harold_V
Posts: 16806
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Brass v.s. Bronze?

Post by Harold_V » Tue Dec 12, 2017 4:23 pm

It would be my opinion that substituting bronze for brass would be quite acceptable, as bronze has qualities that are generally not found in brass.

The chief difference between brass and bronze is the alloying agent. Brass is typically made with zinc, while bronze is typically made with tin.

Unfortunately, the line fades, and the above isn't necessarily true in all instances.

Be aware that some of the bronze alloys are extremely difficult to machine. Some are more difficult than tough steel alloys (I offer manganese bronze as an example).

Phosphor bronze is difficult to machine, while leaded phosphor bronze is amongst the nicest of all alloys to machine. Armed with this thought, it should be apparent that the alloy in question would be considered before making a decision.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Wolfgang
Posts: 70
Joined: Fri Jul 03, 2015 9:47 am
Location: S-W Ontario
Contact:

Re: Brass v.s. Bronze?

Post by Wolfgang » Tue Dec 12, 2017 5:08 pm

I'd cut a small piece and do a little test machining to see how easy or difficult it is to get a good finish in reamed or bored holes; how easy to drill and tap the smallest screw sizes you will encounter, etc. w

pete
Posts: 1419
Joined: Tue Feb 10, 2009 6:04 am

Re: Brass v.s. Bronze?

Post by pete » Tue Dec 12, 2017 7:39 pm

Fwiw and not information gained through actual long term testing. And it would also depend on the exact alloy as Harold mentioned of course. But from my reading Dianne the general recommendations when using bronze is to use hardened shafts for anything rotating within a bronze bearing. For something like a cylinder end cap with the piston rod surrounded by the packing gland it wouldn't matter. I've got a whole lot of bronze here salvaged from various mining parts and some machines like it's much harder than mild steel. It's possibly Aluminum Bronze, or maybe Harolds Phosphor Bronze? Given the tool edge life while machining it with HSS then my best guess is that hardened shafting would be a good idea if it was being used as a bearing material.

User avatar
DianneB
Posts: 575
Joined: Tue Aug 21, 2012 3:05 pm
Location: Manitoba, Canada

Re: Brass v.s. Bronze?

Post by DianneB » Tue Dec 12, 2017 10:56 pm

The bronze I bought 20 or more years ago for a completely different use with potable water purification, a 4" diameter bar of which I have about 8" left.

I don't remember the alloy but it machines beautifully on the lathe. I will test it with drilling & tapping small holes and if handles that easily, I will go ahead a use it.

Thanks gang!

stephenc
Posts: 253
Joined: Sat Jul 05, 2014 6:13 pm
Location: youngstown ohio

Re: Brass v.s. Bronze?

Post by stephenc » Tue Dec 12, 2017 11:36 pm

I tend to look at things from a cheapskates point of view , if the actual material used didn't matter I'd pick the brass every time ... bronze alloys are pretty darn pricey .

On the other hand , if looks are important I'd pick the bronze simply because I like it's color quite a bit more .

Harold_V
Posts: 16806
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Brass v.s. Bronze?

Post by Harold_V » Wed Dec 13, 2017 2:42 am

pete wrote: It's possibly Aluminum Bronze, or maybe Harolds Phosphor Bronze?
It would be difficult to confuse those two. Aluminum bronze has a pale yellow color, while phosphor bronze looks very much like copper. Even leaded, it's quite red.

Aluminum bronze is not fun to machine, either.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Harold_V
Posts: 16806
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Brass v.s. Bronze?

Post by Harold_V » Wed Dec 13, 2017 2:46 am

stephenc wrote:On the other hand , if looks are important I'd pick the bronze simply because I like it's color quite a bit more .
Depends on the bronze. Manganese bronze is, for lack of better description, butt ugly. It's a rather yellow gray color when bright, and darkens to almost black when it oxidizes (takes years). Aluminum bronze isn't much prettier, although it doesn't discolor the same way manganese bronze does. Silicon bronze is commonly used for casting, and machines well enough, but it's tough to machine compared to the free machining grades. Decent color, though.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

pete
Posts: 1419
Joined: Tue Feb 10, 2009 6:04 am

Re: Brass v.s. Bronze?

Post by pete » Wed Dec 13, 2017 3:21 am

Then that almost confirms what it is then Harold. It's definately quite red. Given where it came out of on the saddle blocks that help guide the sticks as the buckets crowded in or out on a P&H 1900 electric shovel then it's likely work hardened real well.

User avatar
Bill Shields
Posts: 4956
Joined: Fri Dec 21, 2007 4:57 am
Location: Somewhere in the World
Contact:

Re: Brass v.s. Bronze?

Post by Bill Shields » Wed Dec 13, 2017 2:54 pm

It won't hurt to go Bronze if you have it or the $$$ is right....as long as it is an alloy that you can machine.

jpfalt
Posts: 978
Joined: Sun Jan 05, 2003 12:55 pm

Re: Brass v.s. Bronze?

Post by jpfalt » Wed Dec 13, 2017 4:22 pm

Use the bronze. Generally speaking, the worst bronze is better than the best brass.

AllenH59
Posts: 362
Joined: Wed Mar 16, 2011 1:26 pm
Location: Prince George BC Canada

Re: Brass v.s. Bronze?

Post by AllenH59 » Wed Dec 13, 2017 10:25 pm

I have some aluminum bronze, and will use it when it is required... It is a pain to turn..

Post Reply