Brass vs Aluminium Vs Steel, questions, questions and questions...

[alexccmeister]

Hi all,

Ever since I got my X2 mill and C3 lathe, I have been playing around with aluminium. Just today I thought why not do some machining with brass and guess what I found out. Brass is easier to tap than aluminium. I thought brass is harder than aluminium, but why is it easier to tap. Also, when I drill hole in brass, the brass bits coming off the drilling is powdery unlike aluminium which is sharp.

I am new to metal machining so apology if the above sound silly. Anyway, after finding out what happen to brass I am now thinking about getting some steel to machine and tap. I wonder if it is easier to tap than aluminium.

Also why aren't people using more brass to work with? Is it because its more expensive? Is brass stronger than aluminium? Thanks in advance.

[rustamd]

steel is cheapest out of 3 you named, probably strongest for most part, aluminum is slightly more expensive but easier to work with, but will cost you that strength, brass is soft and expensive, not much of structural material. Everything is relative to each other. Of coarse everything is just my opinion

[rustamd]

also your speed might be wrong for brass, thats why it was like powder. Try to have correct speed for different materials, tools will last longer, and maybe get job done faster.

[alexccmeister]

Hi Rustamd,

Thanks for the reply. When you say brass is not much of structural material, what do you mean by that? Does it have less strength than aluminium? Or it is more expensive hence not worth to use for structural purposes.

As for the speed, I am drilling at roughly 2000rpm with my X2. I don't mind the powdery stuff, I just find that its odd that brass does that when drilled. I have not milled brass yet so I am not sure how hard it is to mill. I am converting my mill to cnc and thats why I am thinking of using brass to do the job. Since the quantity is small, I am not paying an arm and a leg for the materials. Thanks.

[Crashmaster]

Aluminum and Brass are much easier to tap than Steel.

[rustamd]

Originally Posted by alexccmeister Hi Rustamd, Thanks for the reply. When you say brass is not much of structural material, what do you mean by that? Does it have less strength than aluminium? Or it is more expensive hence not worth to use for structural purposes. As for the speed, I am drilling at roughly 2000rpm with my X2. I don't mind the powdery stuff, I just find that its odd that brass does that when drilled. I have not milled brass yet so I am not sure how hard it is to mill. I am converting my mill to cnc and thats why I am thinking of using brass to do the job. Since the quantity is small, I am not paying an arm and a leg for the materials. Thanks.

Yes, brass has quite a bit less strenght than aluminum.

[alexccmeister]

K. I am using brass rods (3/8") for supporting a nema 23 motor to the X2. I hope the four rods are sufficient strength to support the motor. Any take on using brass as oppose to aluminium rods? Thanks.

[rustamd]

I personally would not use brass on anything that requires some support, at least decent amount of support. For me brass is mostly used on decorative stuff or soft hammers/jaws.

[alexccmeister]

Hmm... Now I will have to rethink my strategy. I was hoping to use aluminium rod, but so difficult to get from where I am. I might try steel rod then. Will see how the brass rods perform. Thanks for the comments guys.

[rustamd]

aluminum should be good for that i would think. My whole machine is made out of aluminum.

[The Blight]

Brass is good when it comes to bearings, valves and moving parts. It's also stiffer then aluminum, but it can't bend too much without breaking (except some special types of brass), but when it comes to structural support, I would go with alu, or steel. You might have a hard time working with steel on these small machines, so have a bit of patience when doing so.

[alexccmeister]

Thanks guys. I have completed the X axis cnc conversion. Using both brass and aluminium. I am using brass for the coupling and rod support for the stepper and aluminium for the plate screwed onto the X axis X2 table end plate.

Tested with mach3 and its working fine. Now onto Y axis. I will put up photos when I am able to. At the moment in my machine shop trying to configure mach3 to run properly with the stock lead screw.