Aluminum 6061-t6 VS 1100 machinability question.

Formability and cut machining ease are not the same thing.

Forming parts requires a high ductility, wire drawing, bending, deep drawing, spinning and die forming come to mind. Many of these alloys are difficult when used in cut machining not under ideal conditions.

6061 T6 has about the best properties/cost that a hobbyist could ever want, there are however some alloys that are less available and machine equally as well or better yet will cost more. 7075 and 2024 T6 are good choices as far as machining.
 
I just ordered a 6 foot length of 1.5"x 1.5" Aluminum 6061-t6 for machining small parts with my mini mill, so far I've been using scrap pieces I had brought from work many years ago some were angles, some 3/8" flat pieces of cut-offs but have no idea what type of aluminum alloy they were.
I searched the net and based on this site, Aluminum alloy 1100 has "Excellent Formability / Workability" but so does 6061.
My question to those of you who have machined different types of Aluminum is, how did you like AL6061 and /or 1100? is one significantly better than the other in terms of machinability? will a newbie to working with aluminum see a difference?
I also priced a small sheet of plastic called delrin thinking plastic would be easier on the small mill(motor/cutting tools) but the price of 24"x 48" x1" was close to $580 :eek: so I'm back with Aluminum for now.
Please share your comments and your thoughts.
Ken
I wanted to add a couple of things on the aluminum. The 1100 is commercially pure (14K-24K psi tensile strength) and the 6061 is an alloy (20K-42K psi tensile strength) with a chemical composition that allows for heat treating. I think it's beneficial for every person to take a quick peek into the properties of the material they're choosing to work with, if they choose the career field or work at it as hobby. There's enough information on material available today that a person doesn't need a metallurgy class or degree. Off the hip I'll say metals have been alloyed for thousands of years and the alloys make the difference in the purpose of the metal and since you mentioned it, the same is happening with plastic. I think gold being worked and used is dated back 30K-40K years BC. then along came copper bronze iron and our modern steel production. Aluminum is an easy metal to work and work with and while the commercial grades do not have the extensive range of alloys as steel, they do cover a wide sector of the market in their use. Unless the material is special ordered by a manufacturer, the heat treatable aluminum grades leave the mill heat treated to the level they are usually intended for market use. With that said, they are not suitable for heavy forming operations but are readily machinable. 2024 and 7075 have tensile strengths equal to mild steel.-Russ
 
At a company I used to work for, we regularly made a small transducer component very similar in size and shape to a sewing thimble. This has been my only exposure to machining 1100-series aluminum, and it was used strictly due to some electrical property needed for the transducer assembly to work properly. I hated that stuff. Like trying to turn stale peanut butter!

No one within the company had ever developed a good cutting procedure for that part, but I was finally able to get something workable pieced together. I remember grinding several sets of HSS lathe tools specifically for that job, and I think the best had considerably sharper angles than conventional aluminum-turning tools. Used either WD40 or aluminum Tap Magic for cutting fluid. Very light cuts at high speed I believe. I am NOT a fan of 1100, but there's more than a little possibility I was doing something (or several somethings) wrong in my approach to working it.

I've always enjoyed machining the 6000-series aluminums. Being primarily alloyed with magnesium, these grades play nice and generally produce what I consider middle-of-the-road characteristics. Tough enough for most applications, easy enough to machine that most beginners can figure them out with relative ease.

The 7000-series material has come to be my favorite. Alloyed with zinc, this stuff is strong, heavy, machines more like mild steel, and can hold very fine detail. I grin just a little when I open a new print packet and see "7075 AL" typed in the material box...
 
I just ordered a 6 foot length of 1.5"x 1.5" Aluminum 6061-t6 for machining small parts with my mini mill, so far I've been using scrap pieces I had brought from work many years ago some were angles, some 3/8" flat pieces of cut-offs but have no idea what type of aluminum alloy they were.
I searched the net and based on this site, Aluminum alloy 1100 has "Excellent Formability / Workability" but so does 6061.
My question to those of you who have machined different types of Aluminum is, how did you like AL6061 and /or 1100? is one significantly better than the other in terms of machinability? will a newbie to working with aluminum see a difference?
I also priced a small sheet of plastic called delrin thinking plastic would be easier on the small mill(motor/cutting tools) but the price of 24"x 48" x1" was close to $580 :eek: so I'm back with Aluminum for now.
Please share your comments and your thoughts.
Ken

I use primarily 6061 on mini mill and lathe. I get most of it from McMaster Carr as it is really inexpensive in small lengths of different sized plate, rod, and bar. On the mill I use 2 flute end mills HSS, I do light cuts to not load the mill and keep the speed 1/4 to 1/2 throttle. On the lathe I use carbide inserts on the Harbor Freight $20 tooling kit, has several cutter holders, several inserts, and the tool to screw the inserts in place with. I keep the speed low and take my time. I get really nice finish, the material is very durable. I use it at work for alignment fixtures. You can use a light oil with cutting like WD40, kerosene but I don't find it needed. Delrin (Nylon 66) is really nice to work with.
 
Delrin and Nylon are NOT the same thing. They're both trade names from Dupont and have some similar characteristics, but Delrin is acetal (polyoxymethylene) while nylon is a polyamide resin. Delrin has more inherent lubricity than nylon, making it well suited for bearings, etc.

Re aluminum, there are many, many alloys out there, but 6061 is the most common as it's "good enough" for most applications, easy to machine, and weldable. It's cheap because they make so much of it. 6063 is also common, and often used for architectural purposes as it's somewhat more corrosion resistant than 6062. Of the 2000 series, 2024 is the most common... higher strength, but not weldable, often found in sheet form for aircraft structures. 7000 series (e.g. 7075) is still stronger, but subject to stress corrosion cracking.
 
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