# Cutting tool for aluminum?



## Amber (Jul 29, 2011)

When cutting aluminum on a lathe or milling machine, what is the better type of too to use? Carbide tipped or high speed steel? I can find both types on ebay, but I would like to get the better tool for aluminum.


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## Michael Glavin (Jan 2, 2009)

Amber,

HSS is best, no coolant is required but a lubricant goes a long way in preventing tip build-up and allows for greater feed rates IMO. kerosene works great as does Reltons A9 and or Tap Magic has an offering too.

Michael


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## Amber (Jul 29, 2011)

Thanks for the info!


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## TrotFox (Feb 15, 2008)

For cutting aluminum just about any steel with do the trick, though non tool-steels will require frequent sharpening.

I use rubbing alcohol as lubricant based on the recommendation of a professional machinist. You do have to be careful not to saturate the room with it due to fire hazard though. ;] I've only caught one lathe on fire while turning aluminum and that was more of a "pop" when some liquid splattered onto the DC motor of the old mini lathe I was using at the time.

Good cutting!

Trot, the gray, fox...


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## Amber (Jul 29, 2011)

I ordered a couple of 5/16ths high speed steel cutters for my old lathe tool holder, I'll be able to do a bit of experimenting with them once they get here.
I need to get a couple of different carbide tipped cutters for doing steel. The one I have is just a triangle that sticks out in the middle, I want to get a left hand and a right hand cutter also.


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## SD90WLMT (Feb 16, 2010)

If alcohol has the ability to flash or ignite...
..I would not use it..

I have always used cutting oils generally used in machine shops to keep my cool!!

The hot splattering oil is still hot when it lands...

Good safety practices are important when using tools of these type..

Dirk


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## chuck n (Jan 2, 2008)

I'll start this comment with a qualification. I have never machined aluminum and the last time I used a lathe was in 8th grade shop, in the early 1950s.

In addition to Dirks comment about alcohol, aluminum in very small pieces, will also catch fire. It oxidizes very easily. I believe that powdered aluminum is the critical component in a thermite devise (bomb). Once it starts burning it will melt through an engine block. I don't know how fine your cuttings will be, just be careful with them. 

Fine steel wool makes an excellent fire starter and aluminum is much more easily oxidized than iron.

Chuck


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## Totalwrecker (Feb 26, 2009)

I have a feeling that Aluminum machines at a lower speed and a light mineral oil should suffice... my qualifications are as exemplary as Sir Chuck's, except I have many years of non ferrous experience....

John


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## Semper Vaporo (Jan 2, 2008)

I think I remember reading somewhere that WD-40 is a good cutting fluid (I won't call it an "oil" because it is terrible to use as a lubricant!) for aluminium. But, I have cut a lot of aluminium on my lathe and mill and generally don't use any lubricant at all.

I almost exclusively use carbide bits -- my grinding wheel is near useless for precision shaping of HSS cutting tools to get the right shape and angles and anything close to "sharp" edges (and I am too cheap to go buy a better one!) (And, yes, it is a poor workman that blames his tools, so keep that in mind as you read this!)

Carbide lasts a long time if you don't do interrupted cuts, like trying to make a square bar into a round one. (Whacking carbide will shatter it and 4 whacks per revolution reducing that square rod to a round one will do it eventually... and is terribly noisy, too!)

I have not generated a lot of aluminium dust while using my lathe or mill, (mostly bigger chips and curls,) but grinding or sanding it will make a big mess if you don't have a good dust abatement method (which I don't!). So I keep grinding and sanding to minimum. I worry more about using a vacuum to collect the dust than I do about it when I make the dusty stuff.

Compacting it in the vacuum canister along with the steel/iron chips I make is worrisome as that is the recipe for Thermite! (I wonder if that is how it was discovered?!)


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## Gary Armitstead (Jan 2, 2008)

Semper Vaporo said:


> I think I remember reading somewhere that WD-40 is a good cutting fluid (I won't call it an "oil" because it is terrible to use as a lubricant!) for aluminium. But, I have cut a lot of aluminium on my lathe and mill and generally don't use any lubricant at all


I have to agree with Semper about using WD40. It IS a terrible lubricant, but it is great for milling OR turning aluminum. Use the spray can WD40. You don't need much. Personally I would use high speed tools. I have had carbide (BOTH mill and turning) get an accumulation of aluminum on the tip of the lathe tool or on the cutting edges of an end mill. I used WD40 in my trade for 40+ years and in my home shop.


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## Amber (Jul 29, 2011)

I'll have to try using the WD-40 for cutting fluid. The spray can certainly makes it easier to apply to the part, especially with the way I'm doing the cutting in a drill press instead of a lathe.
As for making square things round, the first steel wheel that I tried to make was from bar stock. I tried to cut and grind it as round as I could before starting to use the lathe tool. It still took a while to get the piece actually round with the tiny amounts that I was cutting per pass, even with the carbide tipped tool. The wheel did come out pretty well though, considering what I have to work with. With my setup, I can't taper the wheel with the lathe tool, so I took a big mill file to it while the drill was running. It's not precise, but it worked, sort of.
I'm guessing that it will be easier to make wheels from aluminum than from steel.


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## chuck n (Jan 2, 2008)

Amber, not to be a party pooper, but what kind of rails are you using for the aluminum wheels and how tight are your curves? Aluminum is a soft metal, running against steel rails it will wear down. If you run plastic wheels on R1 (LGB) brass curves for a long time the flanges will wear off. 

The closer the hardness of your wheels are to the hardness of the metal of your track, the longer one or the other will last. A friend of mine runs an LGB engine during daylight hours every day he is home. This engine is running on a brass track with R1 curves. Every few years he has to replace the track because he has ground down the railhead and the engine falls between the rails. 

Aluminum wheels on aluminum rails should last a long time. Other metal rails might be a problem, depending on how often you run your trains.

Chuck


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## TrotFox (Feb 15, 2008)

Semper Vaporo said:


> I have not generated a lot of aluminium dust while using my lathe or mill, (mostly bigger chips and curls,) but grinding or sanding it will make a big mess if you don't have a good dust abatement method (which I don't!). So I keep grinding and sanding to minimum. I worry more about using a vacuum to collect the dust than I do about it when I make the dusty stuff.


Another note to be aware of with aluminum... don't grind it using an alumina wheel! Aluminum melts at such a low temperature that it will soak into the wheel between the grit particles. At best, this will result in a smooth, useless wheel. At worst it will cause your wheel to fracture at speed, sending stone shrapnel all over your workshop! Aluminum is best ground with a sander or filed only.

Someone else mentioned getting a buildup of aluminum on their carbide cutting tools. This is a direct result of the cutter getting hot enough to melt the aluminum and having it weld to the cutting edge. Titanium-carbide coated bits (the bright 'gold' colored ones) are frequently used to keep this from happening as the TiN coating is slipperier than HSS. The other thing that will keep it from happening is keeping the workpiece near room temperature... Water-based coolants will do this just fine but Alcohol is better at it (due to it's lower boiling point.) ;] 

I haven't tried WD-40 as an aluminum coolant yet but I'll give it a try next time. I do seem to recall having been told that it works well.

Later taters,
Trot, the well-sharpened, fox...


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## Dan Pantages (Jan 2, 2008)

You can use all these "home" remedies to machine aluminum but if you want to do it properly use Relton A-9 Aluminum Cutting Fluid. This will do a great job on all aluminum alloys and stops build up on your tools.


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## Amber (Jul 29, 2011)

I wasn't aware that someone makes a cutting fluid specifically for cutting aluminum, but it certainly makes sense. I really don't know much about cutting metal, just the basic stuff that I've read, so I'm learning as I go.
If I make aluminum wheels, they'll be running on aluminum or brass track. Right now, I'm using brass code 332 rail that I bought used on ebay for the 4 inch gauge mine tram railroad that I'm building for my 1/6th scale G.I.Joe type action figures.
I found some aluminum round stock for sale on ebay, 3 inch diameter or 4 inch diameter by a foot long. Cutting slabs off that and turning wheels from the slabs makes more sense than using bar stock to turn wheels.
I don't know if I'd bother turning G scale wheels, they're reasonably priced enough that I don't think it'd be worth the effort to turn them compared to just buying them.


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## TrotFox (Feb 15, 2008)

I used WD-40 to make a couple of parts from 6061T6 today and the results were almost as good as with isopropyl. It was much easier to apply though since I don't have a good dispenser.

I'll also have to look into the Relton product mentioned above... I learned most of my skills at a government lab while talking to the professional machinists there. We had an easy supply of isopropyl in convenient dispensers so that is what I have always used...

Trot, the repairing, fox...


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