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Part Off Blade Selection

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  • Part Off Blade Selection

    I just got a quick change tool post that has a holder for 11/16" blades and don't have any that size. I've been using HSS blades to cut the following materials:
    1. Cored bronze for plain bearings
    2. Mild Steel
    3. Brass
    4. Aluminum
    5. Nylon
    This is done on an old Rockwell 10" lathe. What type of blade(s) should I get? I've seen P type, T type, Hollow Ground, Carbide Insert, and it seems to go on for ever. Any suggestions?

  • #2
    You want to use the 11/16" quick change holder, right?

    Then you have to use the type blade that fits it.

    Not all blade styles fit any old style of blade holder.

    Given a choice, I prefer the P style. Re-sharpening is done on the end only. IMO, you should stay away from blade styles requiring sharpening the top side.


    • #3
      Thanks for the help! Since I can't post a picture here, it's at part number 1643-0090. Described as Universal Parting Blade Tool Holder #7.
      Is that a P style holder?



      • #4
        Of the 3 types, none of them really seem to be actually designed for that holder. I had several of the type generally called "double beveled" and have been using them for some time. I think on any of them youll need to take a moment to try and get it as perpendicular as possible in the straight sided holder. If youre gonna order some anyhow, go ahead and get one of each, the HSS ones arent very expensive, and check out how the fit up.

        I sitting here looking in a Shars catalog and a 'P' type in 11/16" x3/32" is $3.90, and in beveled 11/16x1/8" is $4.90. A carbide tipped "T" version is $7.15.

        By the way if you need any more of the QC tool holders, CDCO has the B styles for cheap, that one you got isnt much better, but the regular ones are $12
        If everything seems to be going well, you have obviously overlooked something........


        • #5

          One of each sounds like a good plan. Seems like the double bevel type would be the most stable in this type of holder, but I'll try them all. CDCO didn't have my size, but Shars does.



          • #6
            If I might offer a suggestion, part off blades are not a place to fish the bottom of the barrel. I speak from experience, I did try to use "Indian" and "Chinese" no-brand. Nothing good to report, quite a bit of bad, borderline worthless and FAR too hard by all appearances. They break and chip like you wouldn't believe. You can get away somewhat ok with crap bits for normal turning, but I think that crap parting blades may be at least partly to blame for all the bad press parting gets (that and trying to part steel on tiny/flimsy lathes). I've now got (and had for some time) some better ones that actually work rather well. You WILL notice a significant difference in a side-by-side double-blind taste test...

            That said, I also got a Sandvik insert parting blade a while back and it leaves everything else in the dust.
            Master Floor Sweeper


            • #7
              Mr. Dog-

              Thanks for the Sandvik reference. I'm not shopping based on price right now, I'm trying to move from the rocker post world to the quick change tool post world and don't know what to ask for. What I'm after is a stable parting solution for the materials and equipment listed in the original post in this thread. If carbide inserts and holders are the best way to get a high quality known quantity, then that's what I'll get.
              I looked at carbide inserts and see that there are several variations. I think I need a book or chart or something I can base my decisions on. Anything like that available?


              • #8
                I second the thought on NOT using cheap.

                What size tools can your QC take
                i.e. 1/2 square,5/8" etc

                How big to you plan to part?
                Bushings, solid etc

                Kennametal, Iscar and others make a square holder that will
                part up to 2.5" diameter
                See link below to a Kennametal page. Pics should tell all:

                please visit my webpage:


                • #9
                  I have no idea where you would find a book or the like that covers this. A friend of mine had a Sandvik. I loved how well it worked. He not only had a couple of new spares (bought it from him basically at wholesale) but also has a box full of spare inserts in both L, R, and C configurations. This is the smallest/thinest of the Sandvik blades, they make a variety with different support for max hang out, width of insert/cut and so on. I liked it so much that I've since picked up several other size (much cheaper) on ebay, along with inserts in a variety of styles. Newcomer is often in the Enco sale catalog and seems to get good reviews. As mentioned, there are also versions from Kennametal, Iscar and others. There are also the Manchester "Dog Bones" and many other varieties with varying options and capabilities. I like the "blade style" I currently have, but don't have the experience to say how it fits along side the other options.

                  My main word of advice on that one is check ebay and other alternatives for insert cost. Shopping for price or not, those little fellows are often very expensive compared to what you typically get inserts for. And if you get an odd-ball, then getting inserts cheaply on ebay (or otherwise) may be a problem. With an odd-ball, you may even have limited options for new, which can make them even more expensive.
                  Master Floor Sweeper


                  • #10
                    Oh, and I was using insert parting tools back when I was using HSS tooling almost exclusively. Just for rough numbers on a functional level for my old 11" Rockwell lathe, on a scale of 1 to 10 with 10 being "I can't believe it could be any better" and 1 being "Where's my @#% hack saw!!!". I would put the cheap parting blades at a 2 if I feel like being generous, probably more like 1.5. A good HSS parting blade for most materials is more like a 6 or 7 if kept sharp. Quite serviceable. But that Sandvik with a good/fresh insert is a 9 or 10. Rolls up 4140 like a clock spring, and I've got examples 1" in diameter rolled up nice-n-tight in a lovely blue-purple color. Beautiful cuts and no futzing around with clearances and such, just make sure you get it square and hit the power feed!
                    Master Floor Sweeper


                    • #11
                      The parting tool holder takes 11/16" blades, the other holders are good for 5/8". This set is a BXA or 200 series from Wholesale Tool. Most of my current projects are bronze flange bearings in the 1.125" max OD range, but I will be doing some mild steel, stainless and aluminum up to @ 2.00". Those may have to get sawed and faced.
                      Last edited by Spindle; 01-27-2009, 08:47 PM.


                      • #12
                        Those hold only HSS blades. The typical insert parting blades set square/level rather than using the tool holder to provide rake. I have a tool block that mounts in a common holder. That block in turn holds the blade. Some day I want to make a direct mount dovetail blade holder for my Sandviks, but frankly it works very well now so I'm not terribly motivated.
                        Master Floor Sweeper


                        • #13
                          Forget the parting tool blade holder (put it on ebay)
                          Look at the link to the kennametal page and
                          find A3SCR100416
                          This tool will fit into your "plain" 5/8" holder
                          It has a max cutting diameter of 2.050"
                          A 3mm or .125" insert and the tool body is 5/8" square.

                          I use kennametal only as a reference, as others including Sandvic, Iscar , etc
                          make the same type of tool.
                          I have been using this type for years when making bronze bushings etc.
                          I also found this type of tool excellent for machining various types of plastics.
                          Two tools in one for plastic, Turn and part!

                          PS These can be found on ebay from time to time at great prices
                          please visit my webpage:


                          • #14
                            As this post has continued and you are apparently receptive to broadening your choices for doing parting --- I would like to join the others and say (stress!) that using the holder you have, and using one of the carbide cut-off kits is ... well, theres just NO comparison. I have to say I concur across the board with Bad Dogs use of the 1-10 scale.

                            After a moaning sessions about parting off, one of the more respected members of the forum here (Lane) was telling me about these tools, and having learned to respect his advice, I chose the one already mentioned, from ENCO, the Newcomer. With getting the kit, you'll get everything ready to use with your new QCTP including 10 of the inserts. Get one that takes the narrow inserts, it is much easier on your lathe -- in the Newcomer its .087. Heres the one I chose ---

                            As mentioned, its qualifies for free frt, too --- use code PRPT12 (that'll expire end of the month...)
                            If everything seems to be going well, you have obviously overlooked something........


                            • #15
                              Thanks for all your time and patience in helping a new guy out. What I've learned so far here, on other forums, and some local shops is:

                              1.Mentioning the parting operation strikes near panic in many people I consulted with.
                              2. There are definate strong opinions on either side of the HSS/carbide fence. Since my brother who does most of my lathe work is most comfortable with HSS, I'll have a T-type and a double bevel cobalt blade for him. Since I don't have experience with either but am looking forward to learning, I'll have either the Kennametal or Newcomer insert tools also. Maybe I'll make a convert of him.
                              3. Some lathes (probably my 10" Rockwell) just aren't rigid enough to be very succesful at parting, and a trip to the bandsaw then facing may be the best choice.
                              4. Parting remains a major PITA for even the experienced.

                              Thanks again for all your help, and I'll be back with more first timer questions.