Is there some trick to it? I figured about 5 minutes to cut a half inch of 1/4-24 thread on a 1/4'' brass rod. Well I eventually got it done. I had to grind a taper on the end and bear down as hard as I could to get it to start. I was using thread cutting oil.
Threading brass
- Thread starter labman
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What was the starting OD on the rod? Was it dead nuts 0.250"? What alloy brass?
Of course you will need a taper. And oil. It's cutting....is your die old/dull? Filled with aluminum?
Of course you will need a taper. And oil. It's cutting....is your die old/dull? Filled with aluminum?
You need goose grease as a lube....
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Originally Posted By: Pablo
What was the starting OD on the rod? Was it dead nuts 0.250"?
That's what I was wondering when I read about labman having to give it all.
What was the starting OD on the rod? Was it dead nuts 0.250"?
That's what I was wondering when I read about labman having to give it all.
You'd think brass would be soft an cut easily, right?
That stuff is TOUGH to machine for some reason.
Filing or tapping is ridiculous.
That stuff is TOUGH to machine for some reason.
Filing or tapping is ridiculous.
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I work with brass all the time.
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yes, need special lubricant, as copper and brass don't lift off the tool surface nicely like steel
Kestas
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Leaded grades are considerably easier to cut. I don't know how available they are anymore.
Originally Posted By: mechtech2
You'd think brass would be soft an cut easily, right?
That stuff is TOUGH to machine for some reason.
Filing or tapping is ridiculous.
Yeah, right. So I found out.
Originally Posted By: Pablo
What was the starting OD on the rod? Was it dead nuts 0.250"? What alloy brass?
Of course you will need a taper. And oil. It's cutting....is your die old/dull? Filled with aluminum?
OD? Near as I can measure 31/128''
Alloy? Whatever I found at the Ace hardware in their brass stock.
Oil? The same bottle of Ace cutting oil I have been using for years.
The die? Yes, an old, somewhat used one that didn't come from Hansen.
I had always got by fine threading mild steel rods and had no idea brass would be a pain. It didn't go that bad once I got it started. I was careful to back off plenty.
You'd think brass would be soft an cut easily, right?
That stuff is TOUGH to machine for some reason.
Filing or tapping is ridiculous.
Yeah, right. So I found out.
Originally Posted By: Pablo
What was the starting OD on the rod? Was it dead nuts 0.250"? What alloy brass?
Of course you will need a taper. And oil. It's cutting....is your die old/dull? Filled with aluminum?
OD? Near as I can measure 31/128''
Alloy? Whatever I found at the Ace hardware in their brass stock.
Oil? The same bottle of Ace cutting oil I have been using for years.
The die? Yes, an old, somewhat used one that didn't come from Hansen.
I had always got by fine threading mild steel rods and had no idea brass would be a pain. It didn't go that bad once I got it started. I was careful to back off plenty.
I find brass and stainless harder to machine/thread than CRS.
Stainless steel work hardens something nasty.
I guess brass does "stick" to tools if they are well worn and not lubed at the clean surface.
By alloy - yes it does matter.
I guess brass does "stick" to tools if they are well worn and not lubed at the clean surface.
By alloy - yes it does matter.
Cutting nice threads can be a problem without the right cutting fluids, but as I recall for general / home use brass was usually done dry, aluminum with kerosene or WD40, and steel with sulpher based cutting oil. At a shop one machinist let me use some 'tap magic' or something when he noticed I wasn't getting clean threads, it smelled like cinnamon as I recall, and worked great.
The toughest that I recall working with was a titanium alloy. There are obviously different grades and hardness levels of brass and bronze.
The toughest that I recall working with was a titanium alloy. There are obviously different grades and hardness levels of brass and bronze.
Drilling holes in copper blocks is lots of fun, too.
are you sure you used the correct side of the die?
Free-machining brass (leaded) is still available.
Free-machining brass (leaded) is still available.
sometimes it needs to be said.
I had just done some minor research on brass for work. Leaded brass is available. It's got an exception in Europes RoHS (Reduction of Hazardous Substances) to 3% or 4% max. I think it was Alloy 360 that was the free cutting leaded stuff. Alloy 260 (I think) is Cartridge Brass and is pretty much copper / tin (again "I think", going by memory here). I actually found the leaded brass to be cheaper than the non-leaded stuff at McMaster-Carr, kind of indicates market demand, ease of manufacture, etc. to me.
I've found brass to work OK. Threading the outside of any rod is a pain. The main trick is to start the die true to the centerline of the rod. I'll usually chuck the rod in a lathe, then use the tailstock to press the die to the rod (truing up the centerlines in the process), then (with the lathe in "freewheel") hand-turn the lathe to start the threading. After starting the threads true, rod usually threads OK. Just lots of lube and back-and-forth turning so the chips don't jam in the die.
I've found brass to work OK. Threading the outside of any rod is a pain. The main trick is to start the die true to the centerline of the rod. I'll usually chuck the rod in a lathe, then use the tailstock to press the die to the rod (truing up the centerlines in the process), then (with the lathe in "freewheel") hand-turn the lathe to start the threading. After starting the threads true, rod usually threads OK. Just lots of lube and back-and-forth turning so the chips don't jam in the die.
Kestas
Staff member
What do the machining books say about full threads? Sometimes they recommend 70% or 50% thread for certain materials. This is usually spelled out as drilling the hole to a certain size before using a particular tap.
Cartridge brass is copper alloyed with zinc.
I agree with Rick, using a lathe (or mill) is a superior way to chase a rod or tap a hole.
Cartridge brass is copper alloyed with zinc.
I agree with Rick, using a lathe (or mill) is a superior way to chase a rod or tap a hole.
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