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  1. #16
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    Oct 2008
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    N.W.Tasmania
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    1,407

    Default

    Not at all Kryn, only too willing to pass on info I have come across to anyone who finds it useful. I have learnt plenty from others on this forum myself after all.

  2. #17
    Join Date
    Jun 2007
    Location
    sydney ( st marys )
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    64
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    4,887

    Default

    Is this a new job they are doing or has it been ongoing for a fair while, if ongoing have you asked the older workers how they do it?

    In regards to the tap breaking on the way out, when you felt it grab did you wind it back slightly or didn't you feel it grab?

    In regards to the Tee wrench you may find that you get more sensitivity if you just use 2 fingers of one hand on the end of the handle, I understand what you are trying to do to limit the amount of torque but holding it in close will reduce your amount of sensitivity.

    Are they using lube?

    Are the holes being blown out before tapping?

  3. #18
    Join Date
    Jun 2016
    Location
    Sydney
    Posts
    283

    Default Form Tapping, or Thread Forming

    Thread forming requires a quite malleable or ductile material to work. Most aluminiums are fine, soft (bendable) brass is OK, but running small thread forms into steel is VERY unlikely to be successful. Unlike conventional taps, most thread forming taps (eg from Balax) are $$$.

    For a DxP thread, you will need to drill at least (D-P/2) in diameter - that is nominal diameter minus half the thread depth. After all, the displaced metal has to go somewhere! For M2x0.4, this means a drill either 1.8 mm diameter, or 1.85 mm. The displaced metal rises up and adds to the thread shape, so the thread is just as strong or better than cut.

    Yes, I use thread forming from M2 up to M4, WITH cutting oil.

    Cheers
    Roger

  4. #19
    Join Date
    Nov 2007
    Location
    melbourne australia
    Posts
    3,228

    Default

    Quote Originally Posted by Ropetangler View Post
    If your holes do have a bit of depth, you could try serial taps.
    I can vouch for this. I used this method to tap M3 holes in titanium. It's a tedious process, but much less stressful.
    Chris

  5. #20
    Join Date
    Aug 2008
    Location
    Melbourne
    Age
    34
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    Well it just so happens that the Guhring rep was in today and he reckons they've got a form tap that will work, so we're getting some in to try

  6. #21
    Join Date
    Jul 2012
    Location
    Malvern East
    Posts
    84

    Default Roll Form Tap

    i dont know why people try to cut threads when a rollform m2 tap is available off the shelf

    we would get 500 to 600 tapped out of 1 M2 tap using tap magic on a pedestal drill with a tapping head

    material was 4340 4140 and 316 and on odd occasions super duplex

    A good name brand tap such as Gurhing / Sandvik

    thats all i use know at home

    Good luck with it Bruce

  7. #22
    Join Date
    Jun 2016
    Location
    Sydney
    Posts
    283

    Default

    Quote Originally Posted by jack620 View Post
    I used this method to tap M3 holes in titanium.
    Yeah, it works well with CP Ti, with lube.
    Dunno how well it would go with 6Al4V - be interested to know.

    Cheers
    Roger

  8. #23
    Join Date
    Mar 2014
    Location
    South of Adelaide
    Posts
    1,225

    Default

    I'm assuming the holes are being drilled in a cnc machining center if you are using carbide drills, so why aren't they being tapped in the machine? seems a bit backwards to be tapping production volumes by hand.

  9. #24
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    Aug 2008
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    Melbourne
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    34
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    Nope, they're drilled manually on a Bridgeport clone. The parts are cut by wire EDM, there is one milling operation after that which is done on a CNC Bridgeport clone, but the orientation of the various holes would require it to be done in a 5-axis to get everything in one setup and our 5-axis is flat out doing much more important stuff.

    The quantities aren't huge; about 50 every few months with 2x M2 holes per part. There's also 2x M3 holes, but they're drilled through so we just put a gun tap in a cordless drill.

  10. #25
    Join Date
    Jan 2016
    Location
    Wodonga Vic
    Age
    38
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    633

    Default

    Don't get too worked up over it and take comfort in knowing that last week I snapped a $500 drill bit in a $60,000 hole

    The part was saved and I finished the job with some 5mm cobalt drill bits from Bunnings.... after breaking another two in the part

    Bloody Inconel 718!!

  11. #26
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    Aug 2008
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    Melbourne
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    34
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    Oops!

    I'm not so worked up over the broken taps and scrapped parts, just want to know if there's a better way of doing it so I can learn and do a better job.

  12. #27
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    Aug 2008
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    Melbourne
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    Well, did another batch of them and I am sold on form taps; 45 parts, no hand tapping and, most importantly, no broken taps or scrapped parts (did lose a couple in testing, but we'll take that as a learning experience). Also took a fraction of the time.

    I also discovered the usefulness of number drills; Guhring recommends a 1.85mm hole for these taps, but they only stock drills in 0.1mm increments (we tried drilling them at 1.8, but it really did need that extra .05), turns out a #49 is 1.854

    Dunno why it was never thought of before, I guess sometimes you just get stuck in a "that's the way it's always been done" mindset and you don't even think about it until someone comes in from outside the system and says hang on, there must be something better.

  13. #28
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
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    71
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    5,942

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    That's a big problem in a lot of places "That's the way we've always done it!!" attitude.
    Sometimes businesses need to have a "consultant" come in and work with employees and management to work smarter, not harder, and be more productive.
    I'm finding a similar attitude where I help out, everything is in a rush, has to be done now type of thing. Problem being, that the welds need to be wire buffed before they can be painted, it's difficult to do once the floor is welded in place. No real thought has gone into a system to make it more productive.
    We've built a 5th wheel flat top, it's got 6 wheels on it, then wonders why it takes so long to wire up the side lights, 12 on each side.
    Kryn
    To grow old is mandatory, growing up is optional.

  14. #29
    Join Date
    Sep 2010
    Location
    Lebrina
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    1,910

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    Quote Originally Posted by KBs PensNmore View Post
    That's a big problem in a lot of places "That's the way we've always done it!!" attitude.
    Sometimes businesses need to have a "consultant" come in and work with employees and management to work smarter, not harder, and be more productive.
    I'm finding a similar attitude where I help out, everything is in a rush, has to be done now type of thing. Problem being, that the welds need to be wire buffed before they can be painted, it's difficult to do once the floor is welded in place. No real thought has gone into a system to make it more productive.
    We've built a 5th wheel flat top, it's got 6 wheels on it, then wonders why it takes so long to wire up the side lights, 12 on each side.
    Kryn
    That is one of the worst things about my trade (boilermaker), I was apprenticed to an ex RAAF radio technician - long story as to how he employed a Boilermaking apprentice, but he did, I was and I am one now. He was the best boss as far as stretching the boundaries and inventing new ways of doing the job because we weren't constrained by tradition. When I moved on from his employment, I got hit with the old "we've always done it this way" routine. But why??? Since having apprentices under me, I always listen to their ideas and encourage them. Most don't fully work out, but at least they are thinking about how to do the job better, however I've seen some absolute pearlers of ideas come from those with a fresh perspective.

  15. #30
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
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    71
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    Young lads like that will go far using their initiative, provided that they don't get a job that's "this is the way we've always done it" attitude. I personally think that apprentices, in their final year or two, work in a multitude of places to gain knowledge of different work attitudes, to gain more experiences in the work force. I base these comments on my personal experience, working in about 6 different places up to the age of 26, and no I'm not an indentured tradie, just a lot of expeiences doing different things.
    We have a 3rd year boiler maker apprentice, part time, and sometimes I look for the headphones that tell him "breath in, breath out"!!!!
    I'm continually showing him short cuts, he was asked to extend the legs on some wind up jack legs, he'd cut them OK, but trying to get them straight was another story. He had them laid out on the welding bench (which has more waves than the beach) with a piece of 75X50 RHS on one side, I suggested that he get a piece of 150X50 as a base, then lay the 75 on top so that both become the straight edge. He couldn't work out what I was talking about until I got it out and set it up for him!!!!!!!!!!!
    Kryn
    To grow old is mandatory, growing up is optional.

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