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What do YOU use for internal threading ∅1/2 - 1" ?

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  • What do YOU use for internal threading ∅1/2 - 1" ?

    Looking at my options... external threading not an issue here. Over 1" internal threading also not an issue. I'm looking at my options below that. For less than 1/2" bore, I would buy a tap or, if not available, one of the miniature internal, pre-ground internal threading bits. So I am just curious what is out there that I may not know of. I'm also curious of any feedback on what I do know of.

    I use a lot of Arthur R. Warner HSS inserts (TPMW22_) for plain turning, boring, etc. I also have their 1/2" threading toolholder that takes TNMC 32 NV inserts. I would be quite interested in any feedback on their 1/2" laydown threading toolholder. It is kit K20, takes the same TPMW22_ inserts I already have and, according to LMS, will thread down to .55" ID. Only other idea I know of, to be honest, is a ground HSS blank bit in a simple, broached boring holder.

    One reason I ask is because my experience has led to my general dislike of the design of the Arthur Warner 1/2" boring bar (K14). The threading bar is made along the same design. The shank may be 1/2", but the bar is milled to half of that for the boring length. It is really flexy because the cross section is so thin. Not many makers that I can tell make a boring bar that accepts TPMW221 inserts. I've looked very hard for one, and the only I've found are actually quite nice. They are generic "Made in USA" labeled (alternately, "Interstate") BBN6-2 or BBS6-2 bars. Enco sells them as item number 337-1000 and 337-100, respectively. You can see in this photo why I find them so much more rigid: boring bar In any case, I'm a little skeptical of the Warner internal threading bar for this reason.

    I usually use taps, but when they start costing $40 ea. I would like to explore my options. The impetus for this question is my needing to cut an internal M16x1mm thread FWIW.
    Last edited by Arthur.Marks; 04-15-2012, 04:08 PM.

  • #2
    Arthur,
    Have a look at the threading tools made by MESA TOOLS, they may or may not fit your needs but they are very rigid, work well and will do both internal and external.

    http://www.mesatool.com/index.php?ma...=index&cPath=4
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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    • #3
      You can also make taps. Mine don't always work on the first go, as I don't have much skill at it. But when I do finally get them to cut correctly, it's pretty satisfying.
      I'm here hoping to advancify my smartitude.

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      • #4
        Never used them, so can't vouch but Everede shows a couple of options for insert style threading bars, STH-1000 and CTH-1000 use CDCT inserts, their STH-1100 uses a TBEB insert (the largest of the STH-1100 series is nearest to the general specs you are after).

        Alternately from them they offer those triangular shaped bits pre-ground for 60* threading (used in the 10* and 15* bars)

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        • #5
          The MESA theading tool looks very nice---just a little larger than I am looking at. Makes me wonder if they interchange with the Nickole Mini-Systems tools...

          Everede is more in the ballpark as far as size and cost (the triangular system). I hadn't really looked into that because I thought I read on this list (?) that they stopped making the HSS bits. Enco still lists them, though, as in stock and for sale. Grinding the carbide would have been my issue otherwise.

          Looking further into this, Carmex and the insert-style Everede systems look incredibly nice and versatile to very small diameters. The cost is a little above what I'd like for something that is largely covered by my collection of taps, though. For certain model builders and such, I could see them being just perfect. I'm in the funny spot, though, of seeing what is affordable balanced against buying taps. Some of these inserts are priced at 2ea. equaling most 3pcs. HSS tap sets (which seemingly lasts forever).

          I might give the triangular bit Everede bars a try. I like that the 5/32" bit fits the ∅3/8, 1/2 and 9/16 bars universally. Then again, the system is really not much different from the cross-broached boring bar and square HSS bit mentioned originally.

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          • #6
            I've also taken a tap and ground off all but one tooth on one flute and all but eliminated the other flutes to create an internal threading tool. Not pretty, but it worked.

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            • #7
              As with Dr Stan, I have also made internal threading bars from tap with all the teeth but one removed. Like he said, they are not pretty, but the tooth shape cannot be beat, especially in the smaller sizes.Bob.

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              • #8
                There is a good idea for a DIY threading tool made from silver steel (drill rod) here. http://madmodder.net/index.php?topic=3523

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                • #9
                  I use Everede boring bars with triangular HSS inserts for internal threading. Triangular inserts are open to interpretation so those shown in this picture are what I use:


                  The smaller bar is 17/64 = 0.265 and the larger bar is 1/2", both have 3/8 shanks. HSS bits in this form are available ground for threading but cost more, of course. It is quick and easy to grind your own with a jig, see:
                  http://www.gadgetbuilder.com/ThreadingTools.html

                  The inserts are small so it takes little time to grind them. The HSS used in these inserts is good stuff, holds an edge for quite a while.

                  I got these and other Everede bars off eBay over the years for under $15 each. The inserts were included with one of the bars. The center bar shown is apparently for holding inserts to sharpen them, at least that's what I use it for.

                  John

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                  • #10
                    micro 100's
                    www.neufellmachining.com

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                    • #11
                      Yeah, Micro 100 makes some kick ass carbide tools
                      I couldn't help myself. Bob Ward's link looked so darned easy that I decided to try it out. 'don't think I will have time to give it a test tonight, but here it is:




                      Shank is 15/32" with the neck ~3/8". I'll might stone the cutting tip slightly. I admit, I like it so far. Easy Peasy, cheap and practical. I'll have to report back as I'm using it on 1144.

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                      • #12
                        I had to make a big mounting nut for a part on the school's electric race kart, that was something like 40mmx1.25, or some odd size like that.

                        I hadn't ground my internal threading bit yet (grinding those from a square blank is a pain) and didn't have a tap... of that size.

                        I pulled out the biggest tap I had of the appropriate thread (12mm, I think) and made a few passes with that.

                        Doubt it would be the proper angle if I needed it 100% tight and accurate, but it was plenty good enough to make a mount.

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                        • #13
                          i make my boring bars and threading tools from 0-1 - it really is that easy!

                          i never had much luck with a propane torch though. did you use propane or OA?

                          if it gets too hard it only takes a trip to the oven but i`ve only tempered mine a couple times. i figure it`s just for low speed threading taking light cuts so why bother?

                          nice job!

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