Brass

[hoppercar]

I remember years ago, I used to work for some old coot who always said your not supposed to use carbide on brass?...and now 40 some years later, I still sometimes wonder why ????

[spro]

Forty years ago, it wasn't the same lick?

[Harold_V]

I remember years ago, I used to work for some old coot who always said your not supposed to use carbide on brass?...and now 40 some years later, I still sometimes wonder why ????

Pretty simple, really. At that time, there was no micro-grain carbide, so what one considers sharp really wasn't. As brass has extremely good bearing qualities, carbide tools had the potential to float instead of cut, so achieving size would be a struggle. If the carbide in question had seen use for steel, or other tough or abrasive materials, the problem was all the worse.

You can see a good display of what I'm talking about by using a band saw blade on brass that has seen use for cutting steel. It really doesn't like to cut, although it may appear to be relatively sharp.

H

[John Hasler]

Pretty simple, really. At that time, there was no micro-grain carbide, so what one considers sharp really wasn't. As brass has extremely good bearing qualities, carbide tools had the potential to float instead of cut, so achieving size would be a struggle. If the carbide in question had seen use for steel, or other tough or abrasive materials, the problem was all the worse.

You can see a good display of what I'm talking about by using a band saw blade on brass that has seen use for cutting steel. It really doesn't like to cut, although it may appear to be relatively sharp.

H

Interesting. I've been working at cutting up a large (120 lb) lump of thermite iron. It's crystalline with crystals the size of your thumb and about as soft as brass until it's been worked (it's also weak along the crystall boundaries but not weak enough to make it possible to break it up that way). The sections of bandsaw blade that I use in my power hacksaw cut for a few minutes and then just float. The teeth look normal at that point though I've not looked at them under a microscope. Increasing the downforce gets the cut started again briefly. If I let it run long enough the teeth get rounded off but that takes quite a while. I'm using coolant and relieving the downforce on the backstroke. The blade is 6 tpi. I got it for a dollar at the university surplus so I don't mind using it up (and I expected to) but at this rate I'll have used it all up before I'm a quarter of the way through. Before I mounted the lump of iron up on the saw I tried it out with cast iron and it cut about as fast as my 4x6 bandsaw does. I'm fairly sure the blade is just carbon steel. Brand new, but no label.

Sounds like I should try treating it like brass or copper.

[liveaboard]

I'd never heard that about brass; recently I made a couple of 3/8 brass pipe adapters.
Cut them, bored them, threaded internally.
All with carbide.

[NP317]

Aluminum bronze, and not brass?
~RN

[Harold_V]

I'd never heard that about brass; recently I made a couple of 3/8 brass pipe adapters.
Cut them, bored them, threaded internally.
All with carbide.

With modern carbide, it shouldn't be an issue, although what I said about the tools being superficially dulled by previously machining steel can be.
A great deal depends on the nature of the alloy, too. While some folks think of brass or bronze as being relatively "user friendly", there are copper alloys that rival steel alloys in difficulty to machine. Aluminum bronze is tough, but manganese bronze makes it look like a walk in the park. It readily floats a cutting tool, and dulls tools rapidly. It is unreasonable to machine (demands carbide), but offers extreme wear resistance, so it has its place.

H

[liveaboard]

I have no idea what alloy it was; I used leftover cheapo 3/8" plumbing fittings.
Cuts like butter.

[Harold_V]

Old plumbing castings used to contain lead, and machined very nicely. Here, in the US, that is no longer true, as there's a full on drive to eliminate lead in almost everything. That said, yeah, it does cut like butter. Generally doesn't yield long strings, but instead short dull in appearance chips with a bit of a red cast to them. If memory serves, that's the traditional 85-5-5-5 alloy. I stand to be corrected if I'm wrong.

H

[liveaboard]

It's the same story with lead here in the EU; tin/lead plumbing solder disappeared from the shelves 15-20 years ago, replaced by 'silver' solder.
I doubt there's much silver in it, it didn't cost enough.
I was doing a lot of plumbing at the time, and it was still copper pipe and solder for domestic water, cheaper galvanized thin wall steel tube for central heat loops, with brass compression fittings. Gas plumbing was similar, with some overlapping use of fittings and some particular ones.
Now professional plumbers have switched over to 'unipipe', a sandwich of some sort of plastic with an aluminum core, which is used for everything [water, heat, gas]. cheaper than steel or copper, and comes in 100 meter rolls. Fittings are crimp and require an expensive crimping tool. I haven't used it yet.

The fittings I cut on the lathe were probably from 15-20 years ago bought in the Netherlands, and as you suggested, chips were very fine. they sort of sprayed from the cut.
The parts I made are so thin walled, I wasn't at all sure they would survive machining, but I made 2 without mishap.
They're for heat warning switches in 2 engines, a car and a boat. For some reason, pipe thread warning switches aren't common anymore, and I don't have the tap required for the ones I can get.
So instead of buying a tap, I made the adapters.

[John Hasler]

I just looked up Unipipe: interesting stuff. According to https://www.unipipe.ie/wp-content/uploa ... celist.pdf they have a toolless pushon connector system for it.

Looks like Unipipe is the same stuff as the "pex-al-pex" that is sold here.

[Harold_V]

Interesting to me to read that lead is being eliminated over a large portion of our environment. If memory serves, there are no lead smelters remaining in the US. Indications are that in time, and it may not be very long, lead will be as difficult to deal with as mercury.

There are times when I wonder if, maybe, we are overreacting to some of the things the world is doing these days.

H