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  • Alloys for Machining?

    I've created a new page in the WikiVersity Home Shop Machining text: Materials.

    Problem is, I've no idea what I'm talking about.

    Sooooo....

    If you would be so kind as to answer a few questions, I'll put said answer in the text. Or, if you want, you can put them there yourself (which would be great).

    Basically... I'd like the page to simply answer the question: what do most people use in a home shop environment. Not all the other stuff, what's best for extruding, making jet fighters, or whatnot. Just, what should I ask for at the counter when I go to buy something to machine. Yes, there are lots of charts outlining the benefits and issues with lots of different material, but there are a select few that get picked over the others. What are they?

    When you go to get some metal, what alloy/name do you ask for?

    Steel?

    Stainless Steel?

    Aluminium?

    Brass?

    etc?


    Once I get the common alloys, I can link each to wikipedia articles that describe all the details. It's the common bit that's missing.

    David...

    edit: Maybe an even better way to organise the page would be something like:

    If you want to make XXXX, use YYYY because ZZZZ

    eg:
    Boat fittings, use
    * Naval brass because it resists corrosion and can be polished.
    * 6061-T6 Aluminium because it resists corrosion.
    * etc..

    Might be easier to use, would reduce arguments as more could be added without taking something else away, and would really help out people trying to decide.
    Last edited by fixerdave; 12-31-2017, 05:05 PM.
    http://fixerdave.blogspot.com/

  • #2
    Jeeze, where to start.... Material selection has everything to do with the purpose you're going to put the material to. You don't want to put a low alloy steel into salt water, you don't want to use dissimilar metals together where you'll get galvanic activity, etc. At the same time you don't want to spend $$$ on titanium when aluminum is strong enough. That being said:

    Simple structural shapes being welded together: A36

    Simple steel stuff with something other than drilled holes (some machining): 1018, 1026 for more strength

    Nice fast turning but not going to weld: 12L14, 1144 if you need some strength, 41L40 if you want nice turning with toughness

    Shafting: 1144, 4130/4140 for tough

    Springy: 5160 (leaf spring stuff), Makes pretty tough knife blades, better for long stuff like swords

    Really springy and hardenable: 1080, 1095. 1095 is clockspring stuff, great for small carving tools

    Anything in salt water: stainless: 303/304 for low toughness, 316 for tougher and more corrosion resistance, 400 series for hard, 440C for knife blade

    Aluminum: 6061 for light duty, 7075 for strong/tough

    Titanium: beats the heck outta me

    Bronze: SAE 660 (C932?) for bearings, SAE 68 (C952?) Aluminum bronze if you're into self flagellation

    Brass SAE 360 leaded brass for anything turny or milly, SAE 260 for forming or if you like turning pink gum eraser.

    Plastics: Hey! This is a metalworking forum? Don't touch that stuff or you'll go blind!

    Comment


    • #3
      Addendum: a lot of the choices relate to the old adage: "Anyone can build a bridge that stands, it takes an Engineer to build a bridge that *barely* stands". Many choices can be used outside their particular space - you can make a gun chamber from 1010 if you use a lot of it, but using something like 4140 or 4150 will allow you to make one that weighs less for the same performance and can be hardened to last more than a couple hundred rounds.

      You might want to grab a copy of Machinery's Handbook and read the chapter on steel selection, there's 80+ pages on "Standard Steels" and "Tool Steels" just talking about selection, many more pages following discussing heat treatment, etc. There are folks out there who spend their life on the subject (I'm not one of them).

      Comment


      • #4
        Like the man said, buy what suits the purpose...

        I don't know anyone who buys material "...to machine...".

        Pete
        1973 SB 10K .
        BenchMaster mill.

        Comment


        • #5
          Another part of this relates to what materials are you going to be able to get- you could ask for specialty alloys but you may not find a shop where you can get them. You may have to settle for what is available. Common here for aluminum for example is 6061-T6, with 7075 being much harder to find. If the people in the shop are knowledgeable they could guide you to what would suit your needs- usually what they would defer to for a particular application.

          At one time or another I've needed some steel rod- straight, accurate to diameter, wear resistant, and smooth. Cost was not really an object, especially since I didn't need much length. Induction hardened was my choice, but I settled for hard chromed because it was easier to get. Now I just tell them what I would be using it for, and they recommend an alloy- largely based on how easy it was to get. You get to know what to ask for next time. But- they do have to know what they're talking about. The senior people have all that in their heads, but they are usually too busy to deal with you directly, instead leaving the 'counter person' to fill your needs.

          Tooling is the same for me. When I need a tap for instance, I ask what they use and I've never been sorry to pay what they ask for it. It's usually a higher cost per piece, but cheaper in the long run because the part will work longer and do a better job. I've had the same experience with carbide inserts- I asked for one to do what I needed it to do (interrupted cutting, removing scale) and they sold me one that they use for the same thing. That insert has outlasted many others I've bought that were cheaper (not cheap, just cheaper). I try to keep all this wisdom in my head, but of course some of that has leaked out-
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

          Comment


          • #6
            Originally posted by rkepler View Post
            Jeeze, where to start.... ...
            Exactly where you did. Perfect, and added to the wiki. Still a bit of work to do on linking it into wikipedia, but a great start.

            Originally posted by rkepler View Post
            Addendum: a lot of the choices relate to the old adage: "Anyone can build a bridge that stands, it takes an Engineer to build a bridge that *barely* stands". Many choices can be used outside their particular space - you can make a gun chamber from 1010 if you use a lot of it, but using something like 4140 or 4150 will allow you to make one that weighs less for the same performance and can be hardened to last more than a couple hundred rounds. ...
            Added.

            Originally posted by rkepler View Post
            ... You might want to grab a copy of Machinery's Handbook and read the chapter on steel selection, there's 80+ pages on "Standard Steels" and "Tool Steels" just talking about selection, many more pages following discussing heat treatment, etc. ...
            That is the exact problem this wiki page is supposed to address. If you don't have a place to start, 80+ pages 'aint going to help. We get that problem all the time in the computing world. If a new person slams into a wall of documentation, it's really hard. Give them a first bite, something they can get and hold, then the rest comes over time. I'm just looking for that first-bite page. Wikipedia can give up all the rest.

            Originally posted by 10KPete View Post
            Like the man said, buy what suits the purpose...

            I don't know anyone who buys material "...to machine...".

            Pete
            But... I bet, out of all the possible choices, you have a select number of go-to materials that you use on a regular basis. For "this" you use "that." There might be 30 other choices but you don't even consider them, agonising over material sheets for hours trying to decide on what would be optimal, only to find that you can't buy what you've decided on because nobody uses it. Unless the requirements are way outside of what you normally do, you've already done the agonising, proved yourself right or wrong, and learned accordingly. In other words, you've likely arrived at that list through years of experience. So, why not share it?

            David...
            http://fixerdave.blogspot.com/

            Comment


            • #7
              Originally posted by 10KPete View Post
              Like the man said, buy what suits the purpose...

              I don't know anyone who buys material "...to machine...".

              Pete
              Funny, I do.

              My metal supply place sells it by the pound, but have a minimum purchase. So when I need 12 inches 2 inch bar of easily machined aluminum that can be welded, I end up buying another $20 or more in "future project" metal. It will, inevitably, be machined.

              Dan
              At the end of the project, there is a profound difference between spare parts and extra parts.

              Comment


              • #8
                Originally posted by darryl View Post
                Another part of this relates to what materials are you going to be able to get- you could ask for specialty alloys but you may not find a shop where you can get them. You may have to settle for what is available. Common here for aluminum for example is 6061-T6, with 7075 being much harder to find. If the people in the shop are knowledgeable they could guide you to what would suit your needs- usually what they would defer to for a particular application.
                Yeah, bigger problem is what you can get, not what would be the optimal choice.

                What I can find easily and what is common around here:
                S355J2C that is maybe the european equivalent of 1018. Both hot rolled and cold drawn.
                42CrMo4, usually in prehardened and tempered grade = 'Murican 4140 (PH) for parts that need to be bit harder and tougher than bog standard steel.
                C45 = AISI 1045 round bar stock and key stock.
                Square and rectangular key stock is what I keep at hand in different sizes and its handy for lots of project.

                Comment


                • #9
                  I updated the page a bit.
                  At the end of the project, there is a profound difference between spare parts and extra parts.

                  Comment


                  • #10
                    Originally posted by MattiJ View Post
                    Yeah, bigger problem is what you can get, not what would be the optimal choice.

                    What I can find easily and what is common around here: ...
                    Agreed, and added.

                    Thank you,

                    David...
                    http://fixerdave.blogspot.com/

                    Comment


                    • #11
                      Originally posted by rkepler View Post
                      Jeeze, where to start.... Material selection has everything to do with the purpose you're going to put the material to. You don't want to put a low alloy steel into salt water, you don't want to use dissimilar metals together where you'll get galvanic activity, etc. At the same time you don't want to spend $$$ on titanium when aluminum is strong enough. That being said:

                      Simple structural shapes being welded together: A36

                      Simple steel stuff with something other than drilled holes (some machining): 1018, 1026 for more strength

                      Nice fast turning but not going to weld: 12L14, 1144 if you need some strength, 41L40 if you want nice turning with toughness

                      Shafting: 1144, 4130/4140 for tough

                      Springy: 5160 (leaf spring stuff), Makes pretty tough knife blades, better for long stuff like swords

                      Really springy and hardenable: 1080, 1095. 1095 is clockspring stuff, great for small carving tools

                      Anything in salt water: stainless: 303/304 for low toughness, 316 for tougher and more corrosion resistance, 400 series for hard, 440C for knife blade

                      Aluminum: 6061 for light duty, 7075 for strong/tough

                      Titanium: beats the heck outta me

                      Bronze: SAE 660 (C932?) for bearings, SAE 68 (C952?) Aluminum bronze if you're into self flagellation

                      Brass SAE 360 leaded brass for anything turny or milly, SAE 260 for forming or if you like turning pink gum eraser.

                      Plastics: Hey! This is a metalworking forum? Don't touch that stuff or you'll go blind!
                      Pretty good overall explanation.

                      For steels I would add 1040/1045 hot rolled for general machining. Better strength and machinability than 1018 for roughly the
                      same cost. Definitely our "go to" material for general work. Cold finish 1018 is designed for lower strength shafting where the
                      "as bought" finish is good enough and minimal turning is required. If you're making parts where the entire shaft is turned I don't
                      see the point in paying a premium for the cold finish and then ripping it all off. Of course 1018 cold finish is also very prone to
                      warpage due to the stresses introduced in the cold rolling process.

                      If you're working on projects which will be carburized or nitrided 8620 has lots of strength with good machinability.

                      For aluminum I would add 2024 which I find tends to have better machining characteristics than 6061.

                      Around here 954 alum. bronze is probably the most popular for high strength bushings and bearings...
                      Keith
                      __________________________
                      Just one project too many--that's what finally got him...

                      Comment


                      • #12
                        OK, I didn't pick up on the raw beginner part of this, David. I apologise for that. And Dan, I don't have that access to a yard anymore... used to though...and you're right, I would buy to fill the minimum with material I could generally use, but not just 'anything' to machine. I'm not a machinist, I'm a fabricator. I use materials of all types to make/build what needs making or building. Been doing it for 50 years plus. Metal, plastic, composites, wood, paper, whatever. Professionally, one works the materials the job requires.

                        Personally, however, most of what I do for me these days involves basic materials like 1018, 12L14, 1144, brass or bronze. Very little aluminum. A small portion of the stash is still 'found' material which, when subjected to the 'tool' reveals itself to be useful. Since I do a fair amount of welding still, I'm careful to stamp alloy number on anything other than 1018 or hot rolled shapes.


                        The materials I have in house: (that I know of)

                        1018
                        12L14
                        1144
                        1045
                        O-1
                        360 brass
                        660 bronze
                        6061-T6 aluminum
                        304/308 sstl
                        316 sstl
                        A56

                        I'll see what I can add to your list!

                        Pete
                        1973 SB 10K .
                        BenchMaster mill.

                        Comment


                        • #13
                          Originally posted by 10KPete View Post

                          I don't know anyone who buys material "...to machine...".

                          Pete
                          I buy all my materials in order to know what I'm using and avoid "Mystery Metal" in the shop.

                          A significant majority of what I do is machining parts.

                          Ergo

                          I buy material, most of which I know will be "to machine" ;-)

                          - Nick
                          If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

                          Comment


                          • #14
                            Originally posted by 10KPete View Post
                            ... The materials I have in house: (that I know of) ...

                            A56 ...
                            Added, and thank you, but what's A56? All google is giving me is a road in England and something about sexually transmitted diseases

                            David...
                            http://fixerdave.blogspot.com/

                            Comment


                            • #15
                              McMaster has a good assortment of metals, and a list of properties and uses. Also gives prices.

                              https://www.mcmaster.com/#metals/=1axgbrf

                              https://www.mcmaster.com/#catalog/123/3728/=1axgcu2







                              http://pauleschoen.com/pix/PM08_P76_P54.png
                              Paul , P S Technology, Inc. and MrTibbs
                              USA Maryland 21030

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