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carbide Tooling

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  • carbide Tooling

    I have SBL 9, V-belts with a one horse motor. I have been using HSS forever. I decided to buy the five piece set with the 3/8" three sided inserts. Before I order it, what is the advantage in using this tooling? I have a Aloris AXA holder that will take the half inch holders. The set on sale with 10 inserts (USA made) was only 100.00 Am I wasting my time or is it a good tool for what I do? This will be my first shot at Carbide, so I am open to suggestions. I turn quite a bit of cold roll, and wanted to take a shot at them. Also, how do they work on cast iron? Thank you in advnace, any advise is appreciated. Respect, Verne

  • #2
    I like them mainly because I don`t have sharpen anything.


    • #3
      Advantages are that you always know what the rake is and where to set for enter line. Every time you grind the HSS you have to re set for center line if you grind the top. Also we regularly cut course threads over 1" diameter using a tip instead of changing to threading tool. Dis-advantages are it can get expensive fast if you keep breaking them for some reason.
      They are almost all we use at work. Lots of cold rolled gets plowed thru and they survive if you keep them cool. I am talking up to 1/4" depth of cut on a 6" dia. with a 15 hp machine! Watch out though even with coolant those chips are hot!



      • #4
        On a 9" SB, I think you'll be far more happy with HSS. Inserts like rigidity, speed, and power; none of which the SB9 can offer. They are no where near as sharp as HSS (even ground inserts, much less formed and/or coated), so cutting forces are higher and you'll likely see more chatter; which in turn eats carbide.

        I sometimes used them on my 11" Rockwell, but only when required for highly abrasive (mill scale, cast iron) or hard material. And even then I generally prefered brazed carbide tooling, though I do have some TPG-32x Kennametal holders that I've been known to use...
        Master Floor Sweeper


        • #5
          You can use carbide tooling on a small cone pulley lathe but you can't really take advantage of its productive potential. You need spindle RPM and HP plus overall rigidity to get the surface feet per minute, depth of cut, and feed per rev that makes carbide worth using.

          I don't know why small lathe owners use carbide but they do and with some satisfaction. Anytime I borrowed a carbide equipped lathe I use HSS tooling in it and generally out-performed the carbide in the same class of work.

          And yes carbide doesn't last forever. You still have to sharpen it especially if you are running it at near HSS speeds. Look at the edge of a carbide tool used for some time at too low a speed under 10X magnification. Note the crumbled edge and the smeared metal. This limits size and geometry holding and results in higher tool forces and deflection of slender parts.

          But people will use carbide in these low speed not especially rigid machine tools possibly to avoid having to sharpen HSS tools.

          My suggestion is for these carbide users to devote some time to gaining sharpening skills, tool setting, and feed and speed calculation and the simple decision process for using carbide Vs HSS by assessing the conditions and the goals. The lessons learned pay off at compound interest as home shop workers gain competence and confidence as they venture into more complex work. As in playing the piano, basketball, flying an airplane, performing surgery, or any other activity, the time devoted in learning the fundamentals and practicing the basics pays lavish dividends over a litetime.

          My advice to vdisney is to stick with HSS on the SB 9 except for the very few jobs where carbide is called for, to learn the fundamentals and basic technique, feeds and speeds etc. You will not only get better size holding and finishes, but become quicker and more economical task execution. Practice the basic on remnents and scrap until you become proficient.
          Last edited by Forrest Addy; 08-04-2008, 06:14 PM.


          • #6
            Advantage: New cutting face quickly.

            Disadvantage: Under less than ideal conditions, your $10.00 inserts can become worthless very fast.

            I'm with BadDog & Forrest on this one. I have had far better performance from HSS than carbide on my 9 1/2" South Bend. I have used carbide at home, when appropriate, with somtimes very good, and other times very limited, or no success.

            Carbide gets far more use at work than home, but the lathe at work will run under contidions that suit carbide, namely in machine mass and spindle speed and H.P.

            Carbide while quite tough is brittle and chips very easily. Set-ups that are not ridgid will contribute greatly to chipping.

            Carbide also does not like thermal shock, which means keep it cool or leave it be.

            This link has quite a bit of information about carbide inserts / tooling.

            Last edited by ERBenoit; 08-04-2008, 06:56 PM.
            Paying Attention Is Not That Expensive.


            • #7
              Well I'm gonna be the nay sayer again.
              I use carbide all the time on my lathe, 9" SouthBend.
              I don't use it for form tools and I don't use it on aluminum or brass, but my little machine will rip .040-.060" per side off quite nicely with a small Kennametal tool I have and do it all day long on S7 or A2 tool steel. Never had a rigidity problem and no chatter. As far as sharpening tools, thats fine I know quite well how to sharpen tools as I build molds for a living and run a lathe daily and have for 25+ years.
              A small lathe like the SouthBend will not be able to take full advantage of the benefits of carbide but I can rip more material off with it than HSS can do, and not need lube or coolant to keep it going. HSS will hold up nicely for mild steel but not very long in good tool steel. Cobalt tools take to long to sharpen and the carbide is convenient at that point.
              Carbide will dull thats true, it can also be honed very sharp with a ruby stone or a diamond hone.

              This is an age old argument just like old timers and the rocker posts vs Aloris style tool posts.
              I suggest you try it yourself and form your own opinions!!!
              For me it works great and is money and time well vested!


              • #8
                Only four years experience under my belt ...but i learn quickly .

                This is what I've found opinion ...not necessarily everyone else's.

                Carbide is for taking large cuts...........DEEP AND FAST

                and the large cuts end with a large finishing cut ..

                That means you got to work super accurate ..

                You cant take mincing cuts with carbide until you end up with your finished diameter with hss

                You have to more or less take a few large cuts to get you down to a position were you have one more largish cut ..(thats compared with hss ) finish with ..

                This is because a carbide tool deflects the work, if set up for a mincing cut ....its blunt and rounded .relies on aggressive cuts.

                Also its not very good at all for intimitant cuts will chip and bugger up.

                I have found carbide really comes into its own with cast iron and stainless and other hard or abrasive metals.....very good for brake rotors/disks ..that are impossible with hss

                If you have a DRO..that's when you will see the benefits will also work out you can then do those very few cuts without guessing and measuring and stopping all the know your tool isn't wearing .........and you can get away with no lubrication..
                add to this a quick change tool post .....and you have repeatability .

                you'd be able to churn out item after item .....all bang on .

                southbend nine ...i dont know yet ...

                but it works on my 2.5 hp lathe .

                all the best.markj
                Last edited by aboard_epsilon; 08-04-2008, 08:06 PM.


                • #9
                  My experience (limited as it is) on my 1-1/2 HP 13x24 3in1 has been less than great. I have a friend who is a Kennametal salesman and, fortunately, he sampled me a few that I promptly destroyed. There is a little learning curve involved in the proper use. For me, the time was better spent learning to grind a good HSS tool (and that I practiced with some 3/8 square wooden dowel on my belt sander). I do use some brazed carbides for cast iron and real hard stuff but, I feel way more comfortable with my good old HSS.

                  But hey, that's just me...............

                  I just notice that Enco has a 3/8" set of 5 on sale for $19.99 (SC250-1400), if you just want to try some out on the cheep.........
                  Last edited by smiller6912; 08-04-2008, 09:02 PM.
                  "Those who hammer their guns into plows will plow for those who do not."~ Thomas Jefferson


                  • #10
                    I tried some HSS on my lathe, and had a few tool holders modified for my aloris AXA 3/4" kennemetal tool holders using the tpg 322 inserts, and a Manchester 5/8" parting tool holder. I have never looked back to HSS, and parting was a nightmare with the aloris tool holder using the HSS blade, if I could only use one carbide it would be the Manchester parting tool. I have had problems with finish on some materials, and changed to another insert to correct this, on cold roll I will have to use some oil for a nice finish, but never had any of the problems I read about so much using carbide. I'm still very new to machine work, so I do not pretend to know everything, just my experience. Also I'm not sure how much the lathe has to do with what type of tooling is use (carbide verses HSS) I have a Clausing 4912. Another note I have had poor results with brazed carbide other than the brazed carbide radius tools.

                    Nice thing about the TPG inserts is the wealth of them on ebay and many grades etc, I use a ceramic insert for a super nice finish on Titanium 6AL-4V, and I work with this material a lot. I'm not sure how HSS would hold up on the Titanium, I use cobalt hss drills and have no problems.




                    • #11
                      Well now.. I love carbide. I use it for everything from aluminum, steel, hard steel, stainless and plastics.

                      I use inserts mostly. I dont pay any more than about .25 cents per insert and I have thousands. All ebay buys over the years. I use CCMT, TCMT, VCMT and DCMT and their variants. All positive rake.

                      I also use brazed carbide bits when I want a really fine knife edge. I hone them on a accu-finish hone and can get just as fine of an edge as I can with HSS.

                      I use HSS for formed shapes and some threading.

                      My machines are a SB 10L, Monarch 10EE and a lil Emco 120 cnc. I spin them up as high as I can before the HP gives up the ghost. I turn for purple to blue chips as much as possible.

                      HSS???? Ummm. I guess for the home shop guy there is a HUGE advantage. And even for the Job shop guy. HSS will do everything the carbide will do for the majority of turning. I just use what I have on hand and with a hundred pounds of new carbide on hand I use that. JR
                      My old yahoo group. Bridgeport Mill Group



                      • #12
                        the insert really matters. I like the ccmt's JRouche mentions. If you cut aluminum use ccgt's. They can be had razor sharp. Also try round inserts for a fantastic finish if your work will take the big radius.



                        PS. This is all working ok a oil Asian lathe that I spin fast as JR describes!

                        Try G-Wizard Machinist's Calculator for free:


                        • #13
                          I just started using carbid inserts (DCGT) on plastics and aluminum and think I will stay with the ground positive inserts. At about $5.00 each from Travers (you can get them much cheaper if you shop. ebay, etc) there is no way I want to pay about $15 for a good HSS bit and spend an hour grinding. I can not even think of how to grind such a nice sharp tool with the radius to match the carbide insert. I got the best finish on the work and never did with hand ground bits. I will keep my hand ground ones for mashining rebar!! DavidH.


                          • #14
                            There's always someone who'll tell you it's great, and someone who will say that you need to learn to sharpen HSS, I'm saying both

                            I started with HSS, learned to create my own tools, then to make my own brazed tip carbide then started using inserted carbide, provided I use the correct speeds they all work great for me and I still use HSS parting blades in 3 sizes, some hand groung HSS and some hand made brazed carbide, but for most jobs mainly inserted carbide.

                            Being in the position that I still work & don't have infinite time in the shop, (and if I did the point of being there is to make the things I want to make) I use inserted carbide tooling for all "off the shelf" jobs because it gives me the choice of 20 tools on quick change holders where I can just get on with the work and not have to waste time and mess about sharpening & shimming.

                            You will have to buy at least one tool to experiment with and reach your own conclusions, just dont listen to anyone who tells you carbide is the magic bullet or that it has no place in your shop, they're both more than likely dead wrong,


                            • #15
                              I use carbide extensively on my 9" South Bend with original motor and belt drive. I don't use carbide inserts though as I have solid carbide tooling in sizes and shapes equivalent to HSS sticks. I sharpen my own in the same manner as HSS tools but the difference is for the carbide I run the lathe at top speed. It will take advantage of the carbide if everything is in order. Don't make me post my pic of hard turning with chips on fire again.
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