Cast iron/steel vs. aluminum vs. brass

skogkatt007

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Clearly ci or steel is preferred for machine components. Lots of smaller lathes use aluminum with great success. But what about brass? Is heavier then iron or steel and almost always harder then aluminum I have to believe. For smaller lathe components, is the cost just off putting? The original Sherline used brass, but was replaced by steel ways. Except for some obscure watch making stuff, I don't see brass used anywhere.
 
Yes, brass/bronze are like apples and oranges, it seems that many hobbyists are unaware! of the difference and or uses of each of the two. Bronze is the choice for wear uses, and bear in mind that there are many alloys of bronze for different applications.
 
Ha, just returned from a local metal shop that lets one pick over their drops, came back with some aluminum for tool making. Gonna make a fence for my rotary table that squares up on the t-slot, I think aluminum will work fine for that. Also need to make a two-point clamp to hold down a sandwich of sacrificial aluminum and 0.02" brass sheet to mill some small model locomotive parts, wonder if a 3/8" aluminum bar is beefy enough to not flex so much over the part... ??\

To the OP's question, brass is used a fair bit in scale modeling of railroad locomotives. Fabrication of the major structures like frames and boilers is from brass sheet. A lot of "decorative" parts like air compressors are available as brass castings. Just about any literature on the subject involves the use of brass.

I'm scratchbuilding my first locomotive, a HOn3 model. I started doing it in brass, but at the time the investment in a machine shop wasn't in the cards. Turned to 3D resin printing, works really well for the decorative parts. To make it run, however, it needs some weight, and mechanisms are just easier in metal so I'm now Sherline-equipped and doing a solid brass frame and teeny parts for the rods and valve gear from brass sheet. I may move some of that over to bronze or nickel sliver for a bit of hardness, but I'm learning machining now and having a metal that cuts like butter is handy...

In the same vein, I'm currently focusing on aluminum solutions for my tooling. At some point that'll break down, e.g., maybe the clamp I mentioned earlier.

Feedback appreciated.
 
Bronze is expensive as bar stock though.

Brass wears faster then aluminum? The small lathe (Edelstaal Machinex 5) for which I had contemplated making a new carriage and crosslide for uses brass gibs. The bed/ways are steel, cast integrally with a dovetail. It's a beautiful casting, what rides on it though is pretty flimsy. I could just mill a new heaftier carriage out of thicker harder aluminum. Or very soft steel/iron.
 
Yes, brass/bronze are like apples and oranges, it seems that many hobbyists are unaware! of the difference and or uses of each of the two. Bronze is the choice for wear uses, and bear in mind that there are many alloys of bronze for different applications.
Thanks for this. I feel like a real nit-picker when I correct people, but the differences are important when choosing a material.
 
Thanks for this. I feel like a real nit-picker when I correct people, but the differences are important when choosing a material.
I wouldn't, the materials while looking similar are widely different. If you make a brass bushing, it will wear and you can replace it, not recommending this, but it can be done.

If you make a bronze bushing it could very well wear out the shaft before needing replaced, this is where Olite (bost bronze) comes into play.
 
I still use brass a a bearing surface. It's better than steel on steel, does lubricate,. It does wear but not that quick and I would rather have the sleeve to replace over the steel.

That being said, I use bronze and Oilite when needed or prudent.

There are always considerations. Cost, ease of repair, use and frequency of , etc. all things to take into consideration.
 
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So what would be the preferred material for a new carriage for a small lathe with a dovetailed likely steel (but cast) bed? Once I get my small mill running I figured I could make whatever I want. (The rusty part is the ways if it weten't obvious. The photo makes it look considerably worse then it is. It's all surface rust).
 

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