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Roll Taps (Flute-less Taps)

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  • JoeLee
    replied
    I've seen these for years but have never used them. I can't believe that the shanks don't snap, especially the smaller sizes under 1/4".
    Approximately how much more force does it take as compared to a good sharp cutting tap. Comparing the force to use a 1/4" cutting tap vs the same size form tap, what would be the difference ?
    What is the hardest material that these will work on ?


    JL...........

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  • Dan Dubeau
    replied
    Originally posted by DR View Post

    I believe you were fed a line of crap. Back in the day I don't recall seeing any roll taps being listed as material specific (there might be now though). I bought both coated ones and uncoated, as a rule I would have used uncoated for aluminum only because I usually used everything uncoated for aluminum. In steel the coating or missing coating could give an indication of tap wear which we started to have after a couple thousand holes in steel.

    The grooved relief type were a problem in all materials with deep holes, even though it's a chip-less operation you still get a mush of swarf flakes to clog the groove.

    I have a theory roll taps work best in machines with fixed feed, as in rigid tapping on CNC's or lead screw tappers. Nothing to prove that theory, but then all taps perform better that way.

    We used to keep a running score of the number of holes we'd get for a certain tap, 5200 holes was the highest in 10-32, 7/8" deep in 12L14. We lost the tap in job setup, when the lathe changed tools the tap hit the end of the workpiece and broke.
    Thanks for the info. The ones we have are bright finish with grooves. This tool guy knew everything... so it's a possibility. I've lost count of the # of holes this one has tapped. The previous one was replaced because it was knocked off a bench and broke. Not sure of brands, no info left around. For our needs/purposes they are amazing, but as mentioned about stress, they are not an end all be all solution.

    Maybe I'll start trying them more in steel and see how they work. I know they've done it before, but not being production here it's generally not a big deal to grab a different drill/tap for steel parts.

    Epic, yeah he could have been talking specifically about the coating too. Don't know, it was a long time ago, and I took it at face value and didn't really investigate it much. I got them specifically for aluminum, and they've done that job very well over the years.

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  • Fasturn
    replied
    Originally posted by mattthemuppet View Post
    You worked on the James Webb telescope? That is beyond cool! My neighbour over the road shot the paint on the Cassini probe, which is also super cool. Shame it burnt up/ got crushed in Saturn's atmosphere.

    There are an awful lot of people that are really REALLY excited about the James Webb going up
    Yep was at a table top meeting for a Sun shade mockup. Was used in the parking lot with a meade 10 " 12 years ago. Then the cryocooler which is everything to make it happen. Last was RF feeds up and down links for data. Hope it works??? I have a lot of NGC stock sitting @ $ 391.00 a share? Nothing like working 40ft in the air on the mirrors.

    DR - I used roll taps to open up tight helicoil holes.
    Was not in the specs that we couldn't? In a clean room no metal chips are aloud so the roll tap was our best friend !! They have their purpose, but still not used for flight hardware at Northrop Grumman. BTW.. most everything is threadmilled.
    High quality carbide Hobbs.. 1 1/2 turns and you are done.
    Last edited by Fasturn; 10-14-2021, 04:41 PM.

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  • epicfail48
    replied
    Originally posted by Dan Dubeau View Post
    What makes a roll tap suitable for use in steel or other material vs softer materials like aluminum? The ones that we have at work, I was specifically told by our tooling vendor that they were for aluminum and soft materials only, and don't use them on steel. I never really questioned that, because we do 95% aluminum anyway, but now I'm curious. I know there are different types, like the tri lobes, with grooves etc, but are they all material specific, or was I fed a line of bull?
    Coating on the tap maybe? IIRC, aluminium likes sticking more to some coatings, titanium nitride maybe? Then again, that would only explain why steel-specific ones shouldn't be used in aluminium, not the other way around...

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  • DR
    replied
    Originally posted by Dan Dubeau View Post
    What makes a roll tap suitable for use in steel or other material vs softer materials like aluminum? The ones that we have at work, I was specifically told by our tooling vendor that they were for aluminum and soft materials only, and don't use them on steel. I never really questioned that, because we do 95% aluminum anyway, but now I'm curious. I know there are different types, like the tri lobes, with grooves etc, but are they all material specific, or was I fed a line of bull?
    I believe you were fed a line of crap. Back in the day I don't recall seeing any roll taps being listed as material specific (there might be now though). I bought both coated ones and uncoated, as a rule I would have used uncoated for aluminum only because I usually used everything uncoated for aluminum. In steel the coating or missing coating could give an indication of tap wear which we started to have after a couple thousand holes in steel.

    The grooved relief type were a problem in all materials with deep holes, even though it's a chip-less operation you still get a mush of swarf flakes to clog the groove.

    I have a theory roll taps work best in machines with fixed feed, as in rigid tapping on CNC's or lead screw tappers. Nothing to prove that theory, but then all taps perform better that way.

    We used to keep a running score of the number of holes we'd get for a certain tap, 5200 holes was the highest in 10-32, 7/8" deep in 12L14. We lost the tap in job setup, when the lathe changed tools the tap hit the end of the workpiece and broke.

    Leave a comment:


  • mattthemuppet
    replied
    You worked on the James Webb telescope? That is beyond cool! My neighbour over the road shot the paint on the Cassini probe, which is also super cool. Shame it burnt up/ got crushed in Saturn's atmosphere.

    There are an awful lot of people that are really REALLY excited about the James Webb going up

    Leave a comment:


  • Fasturn
    replied
    Originally posted by tom_d View Post

    I can understand not wanting a rolled thread when specifying a tapped hole as standard policy to prevent stress cracks in a thin walled part. When it comes to AN bolts though, aren't they all made by rolling the thread? I thought cut thread bolts were taboo in aerospace work.
    That's the funny part, stress guys didnt like the cracks ( electron scopes and die ) but the bolts ,tapper head titanium and stainless were all thread rolled. What's not understood is when NASA builds a $ 10 billion satellite, it need to be slightly better than perfect ?? Was true for our division, no rolled tapping on flight hardware. That bird is the J Webb telescope on it way to be launched.
    Last edited by Fasturn; 10-14-2021, 01:01 PM.

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  • Dan Dubeau
    replied
    What makes a roll tap suitable for use in steel or other material vs softer materials like aluminum? The ones that we have at work, I was specifically told by our tooling vendor that they were for aluminum and soft materials only, and don't use them on steel. I never really questioned that, because we do 95% aluminum anyway, but now I'm curious. I know there are different types, like the tri lobes, with grooves etc, but are they all material specific, or was I fed a line of bull?

    Leave a comment:


  • tom_d
    replied
    Originally posted by Fasturn View Post

    Well when you have worked for TRW, and Northrop Grumman for the past 25 years... Yeah you would be fired cuz the stress guys dont like rolled threads! Not that I have anything with roll tapping. Just have to get the minor right or..... Snap ! That's the love / hate.
    I can understand not wanting a rolled thread when specifying a tapped hole as standard policy to prevent stress cracks in a thin walled part. When it comes to AN bolts though, aren't they all made by rolling the thread? I thought cut thread bolts were taboo in aerospace work.

    Leave a comment:


  • Fasturn
    replied
    Originally posted by DR View Post

    Hmmm, are you sure about that? Virtually all nuts are threaded formed.
    Well when you have worked for TRW, and Northrop Grumman for the past 25 years... Yeah you would be fired cuz the stress guys dont like rolled threads! Not that I have anything with roll tapping. Just have to get the minor right or..... Snap ! That's the love / hate.

    Leave a comment:


  • DR
    replied
    Originally posted by Fasturn View Post
    Didnt read all the post, but they are used to repair a damage internal thread. Puts the folded over / damaged thread back in form without removing metal. Many companies ( air craft / space ) do not allow this kind of tapping. They fine for the commercial boys? I have a love / hate for these taps.
    Hmmm, are you sure about that? Virtually all nuts are threaded formed.

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  • mochinist
    replied
    Originally posted by Fasturn View Post
    Didnt read all the post, but they are used to repair a damage internal thread. Puts the folded over / damaged thread back in form without removing metal. Many companies ( air craft / space ) do not allow this kind of tapping. They fine for the commercial boys? I have a love / hate for these taps.
    yeah my shop doesn’t do aerospace work at all so can’t speak for that industry, the customers we do work for covers a wide range of other industries and I look at an average of twenty or so new prints a week for quoting purposes, for the past twenty years and have never seen no roll form tap callout on a print.

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  • Fasturn
    replied
    Didnt read all the post, but they are used to repair a damage internal thread. Puts the folded over / damaged thread back in form without removing metal. Many companies ( air craft / space ) do not allow this kind of tapping. They are fine for the commercial boys? I have a love / hate for these taps.
    Last edited by Fasturn; 10-13-2021, 07:06 PM.

    Leave a comment:


  • tomato coupe
    replied
    Originally posted by mochinist View Post
    We use them down to 2-56 and m2x.04, in aluminum, steel, and stainless 303/304/316, almost daily in a job shop environment. For the smaller sizes we tend to drill and ream
    Yep, they work great in materials that work harden. We use them for blind M3x0.5 in invar.

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  • mattthemuppet
    replied
    that's good to know, thanks.

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