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Ductile Iron for solid tool post?

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  • Ductile Iron for solid tool post?

    Anyone know if making something like a solid tool post for a lathe out of ductile iron is an approach to take if grey iron/durabar G2 is unavailable? I am having a heck of a time finding grey iron that doesn't cost an arm and a leg if available at all as most vendors seem to only distribute for industrial purposes.

    Anyone have recommendations for grey iron suppliers?

  • #2
    I would think that ductile iron is actually better than gray iron because the ductile stuff is 6x more elastic.... but its still 100x more brittle than steel. Its what GM uses for their crankshafts. So I would be thrilled to go with ductile iron. The only place I know of that will deal with hobbyist requests is Windy Hill Foundry. Otherwise you're better off trying to find dura-bar in small pieces from places like McMaster.
    25 miles north of Buffalo NY, USA

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    • #3
      The last one I made was mild steel, a two way rather than four because the design for the indexing was easier. Also, the tools are too long to fit four in a four way without too much hanging out. Ductile iron would be suitable, and much nicer to machine than grey cast iron.

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      • #4
        As for sources, I get drops from my local Alro Metals outlet. They will ship from any other Alro location to my location without charge.

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        • #5
          Have you tried Speedy Metals ?
          They stock gray cast iron.

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          • #6
            When you say solid tool post do you mean removing the compound?

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            • #7
              Online Metals has it too: https://www.onlinemetals.com/en/buy/cast-iron
              25 miles north of Buffalo NY, USA

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              • #8
                Originally posted by Stu View Post
                When you say solid tool post do you mean removing the compound?
                Hi, yes, to remove the compound.

                Thanks for all the replies, I will check out these vendors.
                Last edited by repoman; 07-08-2021, 10:16 AM.

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                • #9
                  I bought an undentified four way NOS toolpost on ebay and it is mounted on the cross slide on a block of cast iron to retain the same tool height. It takes about 5 minutes to change it back to a standard compound. The usefullness of this toolpost which is larger is the ability to hold 25mm boring bars. The added stiffness is also a bonus, but having at least one adjustable saddle stop and slip gauges is necessary to be able to control the X axis.


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                  • #10
                    I used 1144 SP for mine, and it works great!

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                    • #11
                      Originally posted by old mart View Post
                      I bought an undentified four way NOS toolpost on ebay and it is mounted on the cross slide on a block of cast iron to retain the same tool height. It takes about 5 minutes to change it back to a standard compound. The usefullness of this toolpost which is larger is the ability to hold 25mm boring bars. The added stiffness is also a bonus, but having at least one adjustable saddle stop and slip gauges is necessary to be able to control the X axis.


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                      I find that many tool holders of a size that the lathe was designed for hold fairly close limits on the center height, if using 1" shank tooling in a 1" turret well made tools will be nearly spot on. if using using a 3/4" tool just add a 1/4" shim.
                      Sandvik, Kyocera, Kennametal and Widia are excellent at this.

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                      • #12
                        Originally posted by repoman View Post
                        Anyone know if making something like a solid tool post for a lathe out of ductile iron is an approach to take if grey iron/durabar G2 is unavailable? I am having a heck of a time finding grey iron that doesn't cost an arm and a leg if available at all as most vendors seem to only distribute for industrial purposes.

                        Anyone have recommendations for grey iron suppliers?
                        What shape of metal do you need. A round or rectangle? I dont know what type you are making. I will send you the blank to make what you need if I have it. Freebie It will most likely be 4140ph if round. JR

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                        • #13
                          I found it much easier finding bar stock of a size suitable for the plinth I made for my Craftsman/Atlas. As a result, it has a funny looking faceted shape due to dog-earing the corners to eliminate the rough outer radius of the bar. Functionally, it works great, and don't miss the compound as all. The plinth in addition to the cross slide made from a MLA A-11 casting kit, made a huge increase in rigidity for my floppy lathe.
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                          • #14
                            Originally posted by akjeff View Post
                            The plinth in addition to the cross slide made from a MLA A-11 casting kit, made a huge increase in rigidity for my floppy lathe.
                            Yay! Another plug for MLA kits! One of those T-slotted cross slides has been on my "wish list" for a long time now.
                            25 miles north of Buffalo NY, USA

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                            • #15
                              I don't know why you would want to pay more for fancy cast iron for the post. Steel will work as well as the CI, and is much more available.

                              If you are thinking of the rigidity, well, the block of ANYTHING will be pretty rigid.... and why fuss over a difference in the material stiffness when there are at least two oil-filled sliding joints, plus a long thin bed, and more bolted joints in the load path?

                              Just replacing the compound with a block will make a big difference, even if you made the block out of Atlas style zamak.
                              CNC machines only go through the motions

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