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  • Need recommendations for internal thread tool

    As the title says, I'm seeking an internal thread tool, I want one with a carbide insert and small enough to do down to 1/2-13 it needs to be usable in a lantern type tool post and suited to machining hard metals such as titainium and stainless, and be of an appropriate size to fit my 9 or 10 inch lathes. There are so many options with regards to inserts that I don't know where to begin! I don't use carbide much, mostly hss tooling is what I'm used to. Price isn't a major concern here, I need quality above all else. Thanks in advance for your help.

  • #2
    The issue you're going to have for a 1/2-13 internal tool is min. bore and thread pitch. I looked at a couple different toolholders which use 1/4" IC inserts. Both had a min. bore of .500" and neither had inserts that size as coarse as 13 tpi. Reach depth was limited as well. If you step your min. size up a bit it gets easier. For anything 3/4" or smaller I'd just use good taps and leave the single-pointing to anything larger...
    Keith
    __________________________
    Just one project too many--that's what finally got him...

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    • #3
      Is there a reason you want to single point something that small and not use a tap ?
      ~ What was once an Opinion, became a Fact, to be later proven Wrong ~
      http://site.thisisjusthowidoit.com
      https://www.youtube.com/user/thisisjusthowidoit

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      • #4
        I see what your saying, the only reason I need the 1/2-13 is to do a left hand nut for a grinder, but I can grind a hss tool for that, the primary purpose of needing the carbide tool is to do some custom muzzle breaks and flash hiders for a friend and possibly some to sell as well, so nothing on those is as course or small of diameter, I used the 1/2-13 figure as it was the first to come to mind, I kinda need to make that but soon, but certainly not in Ti or stainless.

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        • #5
          If you're not hooked on using inserts, a Micro100 carbide threading tool would be the ticket. Otherwise check out the Carmex kits. Pricey though. I've wanted a Carmex for a while, but now have a building colection of Micro100's. Either way you'll probably need to make a sleeve for your boring bar holder.

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          • #6
            First, I don’t think any muzzle brake should be custom. Most correspond to the standard sizes for suppressors. Stick with those sizes. Make sure the threading is concentric to the bore of the gun, and not to the outside of the barrel. (But that is a different conversation)

            Now in my opinion the best value out there is the Grizzly 5/16” internal threading tool H8302, which will go into a .433 size hole ($33). It uses a 08 size internal insert which can be had in a full profile, or an insert that will do a range of thread pitches. If you are going to do mostly the same pitch, get the full profile. You can get inserts on ebay in the $6-$8 range.

            A smaller internal threading tool uses a 06 size, but the holders and inserts are much pricier. My favorite is the Carmex. I recently snapped a Carmex solid carbide holder in half ($200) in a blind hole. Made me sick. Check out page 945 in the MSC big book, under Ultra Miniature internal toolholders.
            Last edited by Ron of Va; 04-11-2015, 06:54 PM.

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            • #7
              Pardon my ignorance on insert tooling, I think I have holders that will work, I've got a criterion boring bar that I use often and I really like it, it's a ta500btxx 10118 whatever that means (from the wording on its plastic case) and also an enco 377-7010 boring tool that I've never used (forgot I had it, I never used it on my 9" or 10" lathes, it was just too large for the tool post but will fit my new 13" south bend nicely) both of these holders look to take the same insert, so, if the little criterion bar will be suitable the question becomes; what is the best insert to purchase? Any inserts I have or have used, including the holders, have been ones that came in a package deal (buying a box of tools) so I really don't know much at all about the various sizes and interchangeability, all I do know is that the one I've been using has lasted far longer and preformed far better than any hss boring bad Ive used. I wish I knew exactly the insert that's in the criterion bar, it's quite sharp, and cuts very nicely anything I've thrown at it, though mostly steel, I've not tried it on Ti.

              Edit: I don't plan on making them custom oddball threads, I've yet to get the exact specs on the pitch ect.. That will be required on these, I simply know at this point I'll be tackling the project soon and need the appropriat tool to thread them, the barrels afaik are already threaded.
              Last edited by the kid; 04-11-2015, 08:11 PM.

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              • #8
                Two items to think about
                Can you do a 1/2-20 instead ?
                You get better clearances and it is much easier to cut in hardened metals

                Beware of carbide inserts for threading, as you mentioned doing a LH thread.
                The reliefs may be wrong for such a thread

                Rich

                PS, I see you say the barrels are threaded already...too bad, not the best thread for the application IMHO !
                Last edited by Rich Carlstedt; 04-11-2015, 08:39 PM.
                Green Bay, WI

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                • #9
                  No no! The barrels are not threaded 1/2-13 left hand! I'm sorry, I had in mind when I wrote my original post the smallest thing I would be doing internal threading on and that's for a grinder nut that was lost, 1/2-20 and larger would be perfectly suited to my main intended application of this tool, my thinking was If it could do 1/2-13 than it could do the finer threads also needed for this application, I don't know the exact threads on the barrels in question yet, but I know they aren't going to be anything too exotic, in fact they should be all standard, but I don't know what exactly is standard on those, 20 to 24tpi sounds about right but I'm not sure at this time, I've not yet got the barrels in hand to measure.
                  Last edited by the kid; 04-11-2015, 08:54 PM.

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                  • #10
                    I needed an internal threading tool some time again as well. What I did, and it works just fabulous, is took a tap that had a few chipped starting teeth and ground off all but one full profile cutting tooth (just on one side to save the others for the future).

                    It works absolutely amazing! The relief is already there, all the cut angles are right, and the thread profile is perfect!
                    Andy

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                    • #11
                      For short length of internal threads that can't be easily done with a tap, it's hard to beat the Micro 100 solid carbide tools. They last a good long time and can be resharpened on a diamond wheel.

                      That said, I have carbide insert threading tools that can get into holes as small as .280", and that one I've yet to use. In fact, I so rarely cut internal threads without a tap, only two of the 5 internal carbide insert threading tools I own has been used.

                      BTW, I thought the vast majority of threads on guns were 28 threads per inch, regardless of diameter. Is this wrong?

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                      • #12
                        Originally posted by the kid View Post
                        Pardon my ignorance on insert tooling, I think I have holders that will work, I've got a criterion boring bar that I use often and I really like it, it's a ta500btxx 10118 whatever that means (from the wording on its plastic case) and also an enco 377-7010 boring tool that I've never used (forgot I had it, I never used it on my 9" or 10" lathes, it was just too large for the tool post but will fit my new 13" south bend nicely) both of these holders look to take the same insert, so, if the little criterion bar will be suitable the question becomes; what is the best insert to purchase? Any inserts I have or have used, including the holders, have been ones that came in a package deal (buying a box of tools) so I really don't know much at all about the various sizes and interchangeability, all I do know is that the one I've been using has lasted far longer and preformed far better than any hss boring bad Ive used. I wish I knew exactly the insert that's in the criterion bar, it's quite sharp, and cuts very nicely anything I've thrown at it, though mostly steel, I've not tried it on Ti.

                        Edit: I don't plan on making them custom oddball threads, I've yet to get the exact specs on the pitch ect.. That will be required on these, I simply know at this point I'll be tackling the project soon and need the appropriat tool to thread them, the barrels afaik are already threaded.
                        Generally boring bars aren't interchangeable with threading bars. They hold the inserts at different angles.

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                        • #13
                          Originally posted by the kid View Post
                          .... but will fit my new 13" south bend nicely....
                          If you mean NEW as in bought from Papa Grizz,
                          please post a pic so we can drool over it.

                          Thx.
                          -Dooozer
                          DZER

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                          • #14
                            Also note that you will spend more time dealing with springing cuts when threading if you use a steel-shanked tool. Threading has a higher cutting load than boring, so the bar will flex more. I always go for the carbide shanks.

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                            • #15
                              Originally posted by Forestgnome View Post
                              ...I always go for the carbide shanks.
                              Yes. This. And if you don't absolutely have to use inserts,
                              Micro 100 is nice way to go for that reason.

                              --D
                              DZER

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