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  • Beginner tooling question

    I recently purchased a G4003G lathe with a series 200 QCTP. I have been looking over the multitude of indexible tool holders, carbide tipped tools, and HSS bits and would appreciate any suggestions on purchasing sets. So many no name brands look identical but the prices vary.

    My main question is on the use of HSS square tool bits. I have some 3/16, and 1/4" from a previous lathe that was equipped with the typical rocker type tool post and right, left, and straight bit holders. Since there is only 5/8" space in the Series 200 tool holders, do I clamp 3/16 or 1/4" bits directly? Are 2 clamping screws adequate? Any tips on this or links would be greatly appreciated.

  • #2
    You can use the smaller bits in a bigger holder, mostly usually.

    The bigger bits/tools that can be fully clamped under all 4 (there's 4 right?) set screws will be held more rigidly. They will chatter less and you can take heavier cuts at faster FPM (Feet Per Minute).

    But hey, you're probably not doing production work where it really matters if you finish a part in 18 minutes rather than 6 minutes.


    The key to making it work is to have as little tool bit sticking out from the holder as you can get away with. AND, keep the tool nice and sharp with good geometry. AND, the cutting edge absolutely must be at the right height so it doesn't dig in or rubs and won't cut good.

    Your quick change tool post system has some means of raising or lowering the tool. Within limits, it doesn't matter how you clamp the tool in the slot of the tool holder, so long as it's secure and you adjust the height of the cutting tool to be on center. Under some circumstances, I have had to shim a small tool up because I couldn't compensate enough with the height of the quick change tool holder.

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    • #3
      Stay out of those sets of carbide tools they offer, they are just junk. Invest 60-70 squirrels for a proper DNMG holder of proper size for your lathe and get inserts for it
      Amount of experience is in direct proportion to the value of broken equipment.

      Comment


      • #4
        you're fine using small bits in a larger holder. even on the big lathe I'll sometimes use 1/4 bits with some packing underneath - way less grinding to prepare and use them than say a 1/2" bit

        Always use at least two screws to hold them, with only one screw, they can fairly easily move about the axis of the one screw.

        I would recommend to a beginner getting a bunch of hss bits, a book that shows how to grind them (or probably there's lots of web content) and only HSS until you've mastered this. Three days later you can try carbide.

        Do do hss first as it is no more difficult than tying your shoes and is as easily mastered....yet the latecomers to this hobby (in the era of cheap carbide) often skip this learning, view it as difficult and forever are stuck wearing velcro shoes. Good for lots of things, but it looks ludicrous with a suit.
        .

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        • #5
          Thankyou for the quick replies, really helps to form an understanding. Will take the route initially with HSS bits since I have some and also have a grinder set up with CBN wheels. I have some experience at the grinder due to my woodturning affliction and like for V-10, M42, M2, etc. so that should help.

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          • #6
            Originally posted by Jaakko Fagerlund View Post
            Stay out of those sets of carbide tools they offer, they are just junk. Invest 60-70 squirrels for a proper DNMG holder of proper size for your lathe and get inserts for it
            And for the other viewpoint....

            A steel bar is a steel bar. A 70 dollar tool holder has about 1/2 square inch of moderately precise machining, and that's the pocket that holds the insert. The most important part is often the screw. You can buy replacement screws.

            A cheap 1/2 inch shank set will work well for most hobbyists. For beginners, the sets that use triangular inserts are a good choice simply because all the tools in your basic 5 tool set will use the same inserts. The 60 degree tip is also broader than some of the other inserts, so it will wear a little better.

            Examples of the triangular sets using 1/2 inch shafts and TT style inserts.;
            http://www.victornet.com/detail/TTUS-ST8.html
            http://www.shars.com/products/indexa...rning-tool-set
            http://www.mscdirect.com/product/details/78641081

            Note the $150 difference in price for the same basic product.

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

            Comment


            • #7
              I would recommend staying away from the triangular insert tool holders. The shape tip is weak and can be affected by buying cheap inserts. Getting into carbide without knowing good cutting characteristics can be a waste of money for the home hobbyist. And unless you have the horsepower to run them do not buy negative inserts because they have more cutting edges. You will end up sadly disappointed and not have anything good to way about carbide. If you need to look into inserts try the HSS insert tool holders that also hold carbide like DCMT or CCMT shape. You can look into Arthur Warner kits.
              I would stick with the 1/4 to 3/8 HSS bit others have recommended. Less grinding and less money. You can easily make any shape you need. I regularly use them in my quick change tool post with 2 or 3 screws. Sometimes you need to use a spacer to keep the bit directly under the screws.

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              • #8
                Originally posted by mc_n_g View Post
                I would recommend staying away from the triangular insert tool holders. The shape tip is weak and can be affected by buying cheap inserts.
                That's not a very good suggestion. The second chart in the link below shows what process is good for each shape. The DCMT (55 degree nose angle) and CCMT (80 degree) have only 2 cutting edges per insert (assuming positive rake). The DCMT is even narrower than the TCMT. The Triangle shape is usable for more types of situations than any other shape, according to the chart.

                I have holders for many different shapes, and find that each can be "best" in some specific instance. When hogging a lot of material you may want a wide angle like a square, but you will need the power to push that through the metal. When doing a finishing pass, a 60 degree or less is recommended.

                http://www.carbidedepot.com/formulas-insert-shape.htm

                Just my opinion... backed by "some experts".


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

                Comment


                • #9
                  I use a lot of brazed carbide 1/2" square cutters. I have a lot of them in left and right hand, V nose and square nose. You can sharpen them to suit your needs. 3/8" square may work better for your lathe size, that's up to you. I also use a set of 1/2" square indexable triangle insert holders I got from CDCO tool supply. You will find that brazed carbide is better for most machining but there are times when indexable insert holders are handy to have. If you use a carriage stop and are turning diameters an indexable insert holder is handy because you don't have to reset your carriage stop and diameter settings.

                  I would not start buying a lot of tooling just in case you will need it. Buy only as it is needed.
                  It's only ink and paper

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                  • #10
                    I've been very pleased with sets and components from http://latheinserts.com/ .
                    Same lathe.
                    Len

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                    • #11
                      Everyone is entitled to their opinion and suggestions. Listen to all, listen to none.
                      I don't want to see the guy get into a cheap triangle set for his first set on the belief it is going to be the 'bestest' thing ever based upon price and number of points. When it doesn't work I hate to see the trashing of carbide because someone is unfamiliar with it or had a bad experience.

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                      • #12
                        Originally posted by mc_n_g View Post
                        Everyone is entitled to their opinion and suggestions. Listen to all, listen to none.
                        I don't want to see the guy get into a cheap triangle set for his first set on the belief it is going to be the 'bestest' thing ever based upon price and number of points. When it doesn't work I hate to see the trashing of carbide because someone is unfamiliar with it or had a bad experience.
                        I apologize for the rude wording in post #8. I should have said it more diplomatically.

                        In my experience, it's not the insert shape that makes it good or bad. It's the total geometry. That includes clearance, rake, top rake, tip radius, and chip breaker. Then there's coatings and there's the grade of carbide.

                        You can get a crappy CCMT insert with the wrong geometry just as easily as you can get a good one.

                        I have some TCGT inserts that are designed for turning aluminum and they do a beautiful job. I also have some uncoated C2 grade inserts that handle interrupted cuts well. And I've some that turn hard steels on a 7x12 lathe without problems. That's why I say that it's not the shape that determines if it's usable for any particular job.

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

                        Comment


                        • #13
                          Years ago I bought a tangential tool holder that takes 1/4" sq HSS tool bits for use on my 9" SB and have been very satisfied with it. For information on them, here's a random link to one site:

                          http://bay-com.com/product-list.php?...pg1-cid35.html

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                          • #14
                            I have the exact same Grizzly lathe and have been very happy with it. At first I bought the cheap brazed carbide tool bits and was disappointed many times with them. I then started to use the carbide insert bits just like the Shars set that Danlb posted links to. After using them for about 6 months I would never go back to the cheap brazed carbide tool bits. I realize that they are on the lower end of the scale for indexable tool bits but they work great for me. Maybe if I bought some of the more expensive ones I would not go back to the ones that I am using now but they work well and I am satisfied with them. I still use HSS at times and it works well for many things but I really like the indexable tools that I have. I do machining for a hobby and am not in a hurry, Maybe for production work I would be using the more expensive indexable tooling but for me what I am using now works great. Again I agree with danlb based on my limited experience with indexable tooling. Have a good one.

                            Dwight

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                            • #15
                              RHayes, if you've been comfy with HSS with your previous machining don't be afraid to buy a few 3/8 or even a couple of 1/2 inch HSS blanks as well. I will admit to trying carbide over and over again and the massive assortment of inserts in particular is mind boggling. The bottom line is that it's not always easy to find the right inserts. So while you work at learning to figure out the confusion of plenty that carbide produces just be comfy with your HSS.

                              There's certainly nothing at all wrong with working with the small sizes you've presently got. But as mentioned you'll want to limit your depth of cuts and watch out for chatter. I use a lot of those small sizes but mostly for special shapes like small grooving or threading cutters for finer pitches where I won't be chewing out big ribbons of steel. And there's no reason at all not to use these smaller sizes for such things. But for general turning and heavier waste removing you'll want to find some stockier cutters.

                              And once you're at least back to turning THEN start trying to decipher the mysteries of the carbide inserts. And if you figure them out let me know too please?

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