Found three sticks of differing size aluminum round - 1 1/4", 1 3/4" and 2 1/4" that run 4' - 6'. No designations on alloy or hardness. Oxidized a soft gray color, but not flaky or anything along those lines. Is there any reasonable way to get an idea of the alloy or the temper (T-4, T-6 etc.)? By the time I get a sample cut off, it's gonna cost as much as the whole stick. Thought I'd ask before I went back and got the other two. I bought one of the 4' pieces and it cut nicely in the bandsaw. 10 TPI blade and the cut marks (striations?) are close together. An indication of sorts since T-4 seems to have a wider saw blade cut mark pattern. One thing I had thought of was taking my automatic center punch along and also take along some small samples. I have some 5054-T4, 6511-T5, 6061-T6 and 7075-T6. The samples would have been popped with the center punch and marked. A home-made Rockwell tester as it may. Been burned before when a metal supply house guy insisted the 5054-T4 machined great. About like frozen peanut butter - which is to say that it ripped and tore instead of cutting. The cutting bit was very sharp and went on to machine some 6061-T6 with no problems.
Only real way i know to check would be with hardness gauge.If i have trouble cutting i just mess with the profile of the cutter.More or less radius, change the rake positive or negitive.At our shop we use all preground cutters with differant coatings depending on alloy.Not much help for a home machinist.Burl.
There is an acid that we used to use, when doing an I.D. on metals, and the T-6 metals, it would turn black, but the T-4 alloys, ( alloyed with cooper, best I remember), will not change colors.............. Do you have a "drop" you can throw in the lathe, and see if it turns to shit? And, do you machine with coolant, or dry? Sorry, no Machinist here.................Aircraft Sheet Metal type...................
You could try a scrap yard to test it with one of those hand held machines.They have to sort there aluminum.
Yep....do what he said.......and if it were steel.....you could 'spark test' it......next best thing is throw a chunk of eachinto a lathe......turn some shavings really thin........then do a break test on the shavings.........the more brittle........the harder............. Look in your machinists handbook.............
To know for sure, hardness and electrical conductivity will let you know the heat treatment. But you also need to know the chemical composition. Hardness alone on aluminum is not a real accurate indicator. Not a nice linear relationship like steel has. I think your poor man's hardness tester and the file check are both good ideas. Depending on what you want to do with the pieces, it may only matter of they are heat treated or not. T3 or T4 are natural aged, kind of med strength, T6 is max strength, and T7 or T8 are overaged and can be similar to T3 or T4. Any numbers after the first number are just for additional process like stress relief, the basic heat treatment is the first number after the T.
The T-6 and T-4 are heat treat designations, they have nothing to do with the alloy. 5054 is going to be pretty rare to find in round bar stock, outside of specialty houses. 2011 and 2024 will be softer and more free machining than 6061, even though they are both stronger alloys. For most uses, T-3, T-4, T-351, T-6, T-651, T-6511, and T-8 all going to be very close. There is only 2 ksi difference in yield strength between the T-3 and T-8 heat treats on the 2011 alloy. The T-4 and T-351 conditions are essentially identical, as are the T-6, T-651, and T-6511 conditions. The procedures differ, but the resulting properties are basically interchangeable. 2011 is the basis for all machinability ratings in aluminum alloys. It is the best chipping and freest machining of all aluminum alloys. It will file to a gloss with no striations, and will saw with few and even kerf marks. In the annealed condition, it will clog a file post haste, in the T-4/T-351 condition it will not. It cannot be welded in a satisfactory manner. 2024 is harder than 2011, but by much, and is nearly as free machining. Differentiating between these two alloys without a spectrometer test is very difficult. Their strength is very close, so for many things, they can be used interchangeably. It cannot be welded in a satisfactory manner. 6061 is a harder than either 2011 or 2024, and while it has a lower yield strength, it's machinability is only 60% that of 2011. It is gummy (for lack of a better term), and tends to gall on un-lubricated tools. It will clog a file in any condition. Usually found in the T-6/T-651/T-6511 condition. A bend test will show this alloy, as it will crack readily if bent to 90 degs around a radius under 2X the thickness. This alloy welds readily and is the most commonly used all purpose alloy. Welding will remove the heat treat in the HAZ, significantly reducing the yield strength in that area. 7075 is harder than 6061, and is nearly twice as strong as the other common alloys. It is usually found in the T-6/T-651 condition. It has a machinability rating of 80% when compared to 2011. It will not easily clog a file in the T-6/T-651 condition. It is not usually found in the annealed condition, and cannot be satisfactorily welded. Take a single cut mill bastard file and your automatic punch with you, and see what you can find, though I would be VERY suspicious of any material that does not bear the printed alloy and heat treat information. EVERY major manufacturer prints this data every 8" on the surface of every bar of material they produce. If this material is missing this information, I'd be inclined to ask why, and maybe find a vendor that can provide paperwork to identify the material they're selling. I'd never use a piece of material I couldn't ID for anything I needed to count on (suspension parts, steering, safety brackets, etc).
Nice info cool Hand...! The last statement is worth its weight in gold. I would only add two things The ( bring a sample ) idea is good for a comparo - but I would use a couple bran new 1/8 drill bits & a cordless drill - You will see both Hard & gummy right away. The second bit would be try a newer style high helix coated end mill - I have had impressive results with them.
Yeah, I've had very good luck with variable helix ZrN coated three flue end mills. My feeds and speeds went up about 85% just from changing tool geometry. Good stuff.
Terrific information for a home shop owner. Thanks. Most machining is done dry with carbide TPG-321 inserts although I've been grinding some HSS bits as the books show and like it better for aluminum. Even so, a new insert puts a very nice finish on aluminum. I like WD-40 as a cutting fluid on aluminum. A gallon can lasts a long time. Used mainly on deep hole drilling. The sticks - or billets - are from an aluminum salvage yard and I think the markings are simply worn off from handling and weather. I sawed off a piece, faced it and cut it to OD for threading. Machined easily, nice long curls, a lot like 6061 T6 which it probably is. (I need to grind better chip breakers.) Most of the aluminum I get from various places is 6061 T6. It's not a critical piece, well it sorta is, but high strength doesn't enter into it. It'll be a screw-on filler tube and gas cap for my 32. I was stupid last Thursday and left my recessed aircraft cap on the deck lid and drove off from the gas station. It fell off. I went back and found it, but it was smashed and broken. Therefore a new filler tube and cap are being made. That because no aircraft caps around here or at the airport. Delivery takes a while and they are expensive. Not sure what my particular one would cost, I saw some for $50. and one for $900. This last one a rare cap for a restored aircraft. Anyway, if I did stumble onto another cap like I had, the original aircraft adapter I made for the car is still in service and this replacement cap and filler tube can be easily removed and another aircraft cap installed. The aircraft cap and the one shortened axle - besides some speed equipment are the only non-stock items on the car. Barring major breakage I could get the car going again most anywhere. Thanks again for the info, much appreciated....
A few years back I ran some simple tests on TN coated and ZN coated 1/8" drills in 1/8" mild steel. The TN drills did the best. One really interestng one I found was that I could use the shop's fluorescent lights as a strobe system for the correct drill speed in a variable 3/8" drill motor that turns up some pretty good revs. That helped the drills to last longer and made the test somewhat repeatable. When the drill flutes stood still, the speed was correct. Too slow or too fast would have the flutes visually traveling so it was easy to slow down or speed up until the flutes stood still due to the stroboscopic effect of the fluorescents. Accuracy with a fluorescent light used as a strobe will be quite good. I used to operate power stations and the system frequency seldom varied more than a few hundredth's of a cycle over the span of a few weeks or months.
My experience has been the exact opposite where TiN and ZrN coatings are concerned. The titanium nitride (TiN) is very good in mild and low alloy steels, but it has an affinity for aluminum, such that the coating actually promotes built-up edge, which leads to gullet plugging and ultimately tool breakage. Just about anything will work to drill one hole, or many holes by hand, where you can see what's going on and feel what the tool is doing through the grip of the drill motor. With CNC equipment, there is no feel, and there are no second chances. If you make a mistake, you break the tool and likely scrap the part. You survey the carnage, decide what went wrong, make a new plan, and start over from square one. When endmilling, my weapon of choice used to be a two flute, 40 deg helix, right hand cut, right hand flute, uncoated, solid carbide, center cutting end mill, usually from Niagara. I could take a depth of cut (DOC) of 0.150" at 5,000 rpm, feeding laterally at 40 inches per minute (IPM). That is a chip load of 0.004 inches per tooth (IPT). With water soluble oil based flood coolant, I could get about 25 hours of tool life, with no plugging or built up edge (BUE). I have since switched to a three flute, variable helix angle, right hand cut, right hand flute, Zirconium Nitride coated, solid carbide, center cutting end mill from either Accupro or Lake Shore Carbide (both have been excellent). My DOC has gone up to 0.250", my speed remains 5,000 rpm ('cause that's as fast as my spindle goes), but my feed has gone all the way up to 90 IPM. That's a chip load of 0.006 IPT, 50% greater than before, with no BUE, and my tool life is just about the same, but slightly better at 29 hours average. That's a smokin' increase in productivity, where the only changes were that of tool geometry and coating. Before I started using the uncoated two flute tools, I used two flute TiN coated tools at the same data. Using the same coolant, they constantly suffered BUE damage and gullet plugging, which resulted in several broken tools. The carnage forced me to look at my process and do some research, where I found that TiN is a very poor choice for machining aluminum, because they are so fond of one another. All the data I've listed is in reference to 1/2" OD x 1.25" LOC solid carbide end mills. The results and trending are valid across the entire size range, obviously, but the actual cutting data (particularly the feed per tooth data) will differ from diameter to diameter. For turning, you should look into a few of the new chipbreaker geometries offered in the CNMG type inserts. They're negative rake, so not really good for tiny machines, but if you can support them, they are worth a look. Negative presentation, but a high positive cutting edge with very aggressive chipbreakers to stop the stringing in aluminum and stainless steel. Wide range of coatings available too. So long as you can machine it, any of the discussed alloys should be fine for your fuel filler tube and cap. I just wouldn't build steering couplers or leaf spring hangers out of the stuff.
C9....Have you been to Industrial Metal Supply in Phoenix yet? Its like a grocery store for metals. Everything is on the shelves labeled, pre cut, indoors, and air conditioned. The back room has shelves full or drops and rem's.
No, but I'll put it on the list. My pals go down there about twice a year and I usually stay home. Sounds a lot like Industrial Metals in San Fernando. Their remnant shelves are great. A few years back they were really great and sold the stuff by the pound. Couple of years before I left Sunny California they started selling it by the piece. Prices went up about 5x. Still went there, but more for their wrought iron gate stuff and mild steel as well as aircraft bolts by the pound. The place could be hazardous to your checkbook....
Lotta interesting info. The TZ drills I tried were from Sears and probably not as tough as one destined for industrial use. At 5 grand you must have some interesting explosions. My lathe is 12" x 36" and I don't know if it would handle a negative rake tool or not. All of my end and side mills are HSS. I picked up a few good ones a while back when I bought an old machinists toolbox full of goodies. CNC answers the question of why Lockheed in Burbank was selling tools for a dollar a pound. They were used, but seemed pretty sharp. Not quite as sharp as some new ones I have, but they did cut ok. I haven't tried any of the roughing mills, but would like to. Most of my mill work is simple stuff and the mill proper is one of the larger drill-mills. Just missed a good ol Bridgeport before I moved to Arizona. After we got here, my pal offered me his WW2 era Bridgeport, in trade for my little mill, but I turned it down since mine is pretty well accessorized and he wanted all the stuff. He eventually sold it and the new owner painted it, polished up a few pieces, bought a few endmills and is doing great with it. I don't use the mill all that much, maybe one use of the mill to thirty uses of the lathe and I'm still glad I didn't trade....
Without getting too technical I reccomend 6061-T6. It machines great and it's readily used in motorcycle, automotive, and aircraft application. I buy it though www.metalexpress.net . They have more profiles and diameters than you can think of, and they cut it to rough length for you. They ship it asap, and you only pay for what you need vs. a 4' 6' length. I have personally machined many parts out of 6061-T6 and I highly reccomend it. As far as determining hardness goes. You can look up your specific aluminum material properties online to determine a rockwell hardness spec. You could test your pieces but you would need access to a hardness tester.
C9, My opinion on the aluminum is that it is cheap enough to buy exactly what you want instead of getting something that may or may not work, but that is just my opinion. Unless you are getting the stock for free, it may not be worth messing with. Coolhand, I have found that machining aluminum with uncoated tools is the best, flooded with coolant. As for your example with the 1/2 in endmill, I like to use YG-1 banshee endmills. They are 2 flute high helix and you can haul ass with them. I used their endmills, helical entry at 3 degrees, to a depth of 1.25 and sidemill with them. I was getting .150 stepovers at 500ipm at about 12000 rpm, so you could probably run it at 300 ipm no problem, provided the machine will run that fast accurately.
Jay, this is a remarkable insight. Thanks for mentioning it's usefulness. I think Al (being softer) usually called for higher cutting speeds than steel, but it's been a while.
Yeah, you're right on that. Only a couple of places to get 'new' aluminum here. One has to order it in and the other had lots of cutoffs in their machine shop, but started charging $37.50 per cut. Their greed made me quit going there. There are a couple of aluminum recyclers here and once in a while a billet will come in. At a buck a pound it's worth a shot. The aluminum I really like to work with is - I think 7075 T6. One of my co-workers brought in from the rem drum at the machine shop across the street from the power station in an industrial park. Used to make F-16 fuel valve bodies I understand. It's really sweet stuff, but most of it is in big square blocks so it gets saved back for special projects. I really hate to cut a 4" round down to 2 1/2". Takes time and wastes material, but sometimes ya gotta go with what you have. I can't find the last piece, but a pal gave me several 1" thick looks similar to blanchard ground steel plates in 6061 T6. Cut more than a few hexes out on the bandsaw and made em round in the lathe. It's surprising sometimes where you can find good billets of aluminum. Catch a few at garage sales once in a while. Usually oxidezed pretty good so the owners don't think it's worth much. One clean-up cut brings out the beauty within and like Little John said once upon a time, aluminum is easy. "Making a gas cap? Just cut everything away that doesn't look like a gas cap...."
I have two speeds that I run on the lathe. Aluminum speed and steel speed. Excepting for back gear stuff. Nice part is, they're adjacent to each other on the step pulley so it's easy to change. I machine stainless once in a while and steel speed works for that as long as I use carbide.
Yeah, I would have liked to stay with the two flute uncoated tools, but I don't have the spindle speed to get the fast travel speeds. My spindle on the CNC tops out at 5,000 RPM, so it's barely running fast enough to push aluminum properly anyway. I'd be doing what you're doing if I had a 15,000 RPM spindle, but my machine is too old for that technology. I sure do want it though. Want it real bad. lol In my research, I've found guys cutting aluminum at more or less whatever the fastest speed on their machine is. On YouTube there is a clip of a Mori Seki horizontal face milling and end milling aluminum at 40,000 RPM at something like 600 IPM (IIRC anyway). 1" end mill, cutting at full width (slotting), and a DOC of 1.5", at 600 IMP. That's some metal removal there. The machine was literally howling. I wouldn't want to be in the same building with it for any length of time. Machine tools are at least as addictive and expensive as hotrods and race cars, if not more so. The upshot is that the machine tools can earn their keep once in a while.
I had a piece of aluminum square that was 46" by 46" (yes almost 4 feet) by 9 inches tall that I had to cut round to 45.5" with a parabolic curve on the top, which was the most fun I had running a machine. It was run on a highspeed 5 axis machining center, 22000 rpm and 1200 ipm feed and rapids. Bad part with the machine was that I could only run a .625 endmill in it, any bigger would chatter and run like shit. So I did this part with that .625 2 flute at 1.5 doc and .300 stepovers, 22000 rpm. It literally blasted the paint off the inside of the machine My boss was pissed that his $750,000 machine had the paint blown off of it, but was really happy that I did a $30,000 job in 10 hours There are several ways in my opinion to do high speed machining, I look at it more as high efficiency machining. Material removal is just part of the entire scheme. C9 If you need some material, there is a place in Fort Wayne, IN called metal supermarket that sells pretty much any aluminum size you would want, no cut charge. Their prices are marginally higher than other places, but with no cut charge, they fall well below what you would pay at some of the high end distributors. I have also found that lately with the economy in the shape it is in, some of these places that hadd the hefty cut charge have dropped their charges to stay competitive. Also try online metals, they are a good place to get an instant price to let you know what you can get the material for. Hope that helps some
You guys are the fuel drivers of the machine world. Geez. Hot rods can earn their keep. Sometimes people will pay to see your taillights....
Thanks for the metal supermarket info. I'm kinda missing the Fresno and San Fernando metal supply houses as well as the surplus metal houses I used to go to. Next time I head down the hill to Laughlin, Nevada I need to check the metal supply house in Bullhead City, Arizona. They're across the river from each other. I'm curious as to what kind of chucks or collets you guys use in your high speed machining? I've heard stories of some lathe chucks coming un-glued due to high RPMs. I'm thinking they may have been cast iron chucks. The chucks I have are smaller, running from 3" to 8" with an independent 10" sitting in the wings with backing plate ready to go, just need to cut a register and drill it. Pretty sure most of them are semi-steel with perhaps the 8" and 10" independent being cast iron. Granted, the 3" chuck looks a little silly on a 12" lathe, but it's a lot handier than you would think. Since I have lots of time compared to a shop I don't mind if it takes a little longer.
What I used for high speed machining, in a mill, is heat shrink toolholders. Basically the toolholders are made .0005" smaller than the tool you will be using. You heat up the toolholder and drop the tool in, as it cools you have a press fit. Standard collets have anywhere between 150 and 300 psi holding power, where shrink fit holders have approx. 800 psi holding power. These holders allow you to be very aggressive and not pull the tool out of the holder, although I have had that happen to me These holders are also balanced at G2.5, or about 25000 RPM. I am not sure about lathes, as I have only worked with one high speed lathe, it turned 6000 rpm. It had a hydraulic 2 jaw chuck which we milled the profile of the part into the jaws and held the part that way. The parts we were working on were just ball valves, I think the largest one was only 2" in diameter. I am not sure that bigger lathes need the speed like a mill or small lathe does, as the bigger diameter dictates your surface speed. And it scares the shit out of me to run large parts at high rpm, I have had parts fly out of the chucks being too aggresive<!-- / message --><!-- sig -->
True confessions here. I just came in from the garage/shop where I was threading the male side of the gas cap. The female side that sits on the deck sail panel - just behind the rear cockpit edge - is threaded and ready to go. Got that done one day and was doing the gas cap today. Havin' a helluva time getting it to screw together. It'd go about half way and quit. No taper on the male or female parts. Nothing in the threads on either side that would hang things up. I'm thinking, ok, I haven't threaded anything for a while, but I did have the correct setup etc. All except for the TPI count. The female threads are 11 TPI and the male threads are 10 TPI. I missed the right slot when setting up for the cap after machining it to almost finished. That's almost as bad as the first threading on the lathe I ever did. Cut a test plug same as the lathe's threaded nose for the chuck backing plate I was making . . . nothing like jumping in with both feet. It fit the other chuck's backing plates just right so it looked to be a good test device. Cut out the backing plate proper, it measured about where it should have, but I couldn't get the test plug to screw in. Made a couple more cuts and it would only go a tiny bit. You guessed it, I cut left hand threads. Machined those out, cut a plug, did the interference fit bit and then bored and cut the threads. Not too embarrassed about that, it's all a learning experience, but the 10 vs 11 TPI was dumb.... Good thing I bought a billet....
Im suprised no one has started a machinist social group.Learned lots of infomation on aluminum on just this one post.Looks like there are plenty of talanted machinist that lurk on this board.My work on aluminum is limited to my home shop.During the day our shop builds molds out of Hardened tool steel,50-60 rc., witch is a totaly differant animal.We have spindles up to 32,000 rpm with unbelievable material removal rates.Burl.
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