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Thread: Thread Quality

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    Quote Originally Posted by barbter View Post
    Repeat - NO i didn't miss it i was keeping this on track because the OP originally said they tap '000s of threads a day.
    Which means tap = smaller holes, and not big holes which are threadmills.

    Why do you feel the need to keep deleting the stuff i write - you ask me a question i answered it and you delete it.
    Again you are sidetracking a thread. I didn't ask you a question and I don't delete your posts that are helpful to an OP.

    You seem to have a mission but keep me out of it. It seems to me as if I am your "mission".

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    Quote Originally Posted by barbter View Post
    All of them.
    Otherwise they'd go out of business.
    And standard practice calls it a thread core diameter, not a thread bore.
    You haven't visited many shops and not all work within aerospace.

    Don't keep making snide remarks directed at me and your posts won't be deleted.

    Re what I refer to as bore diameter if I went by the book I'd refer to it as "minor diameter" with the "symbol" D1. I was quality engineer at an aerospace company and now I have several as customers.

    If you are as clever as you think you are then write helpful post that aren't intentionally provocative.

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    Quote Originally Posted by Christy K View Post
    My company taps thousands of parts on a daily basis. We use standard go/nogo gauges to check for product quality. We are now wanting to take that quality check to the next level. Does anyone know if there is a gauge or some kind of measurement system that can monitor the amount of torque/force a thread gauge needs to pass through the threads?
    Please reply to post #2 when you can.

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    Quote Originally Posted by Gordon B. Clarke View Post
    Again you are sidetracking a thread. I didn't ask you a question and I don't delete your posts that are helpful to an OP.

    You seem to have a mission but keep me out of it. It seems to me as if I am your "mission".
    Hahahaha!
    Really.
    I shake my head

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    Quote Originally Posted by Gordon B. Clarke View Post
    You haven't visited many shops and not all work within aerospace.

    Don't keep making snide remarks directed at me and your posts won't be deleted.

    Re what I refer to as bore diameter if I went by the book I'd refer to it as "minor diameter" with the "symbol" D1. I was quality engineer at an aerospace company and now I have several as customers.

    If you are as clever as you think you are then write helpful post that aren't intentionally provocative.
    You are wrong about me on so many things.
    And i don't care where you say you worked as it is unimportant.

    Back on track - i was purely correcting your terminology because a bore is a bore and a core is a minor diameter.

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    Quote Originally Posted by Gordon B. Clarke View Post
    Have you ever known any "QC people" that would do that or do you just dislike "QC people"?.
    Everyone who has been around a bit in this trade has encountered a bad QC person. Be it ignorance, arrogance, or plain laziness, they exist.

    And when you've had to work with one for a while it takes a long time to forget it.

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    Quote Originally Posted by gregormarwick View Post
    Everyone who has been around a bit in this trade has encountered a bad QC person. Be it ignorance, arrogance, or plain laziness, they exist.

    And when you've had to work with one for a while it takes a long time to forget it.
    Of course I've known bad inspectors but never quite like as described in post #9. What inspector would try and scrap good parts for "praise" and hope to get away with it?

    The lazy ones in my experience would rather just approve bad parts rather than have the bother of filling out paperwork.

    Maybe the "mindset" in different countries is more than I thought possible.

    Some inspectors are better than others just as some machinists are better than others. No company can survive over time what could become almost civil war. Management must act.

    This thread is now far removed from what the OP intended

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    To the OP, this is one option: Rotary Thread Inspection Tool | Thread Check

    Or, if you care to take it the next - next level, then these: https://www.johnsongage.com/wp-conte...ries-GJ-GJ.pdf

    The gauges in the first link certainly look excellent for small mass produced threads.

    The gauges in the second link look as if they are more for larger internal threads.

    Certainly interesting options for those mass producing internal threads and probably solve the OPs issue with torque.
    Last edited by Gordon B. Clarke; 01-27-2020 at 02:28 AM.

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    Quote Originally Posted by Gordon B. Clarke View Post
    Of course I've known bad inspectors but never quite like as described in post #9. What inspector would try and scrap good parts for "praise" and hope to get away with it?

    The lazy ones in my experience would rather just approve bad parts rather than have the bother of filling out paperwork.

    Maybe the "mindset" in different countries is more than I thought possible.

    Some inspectors are better than others just as some machinists are better than others. No company can survive over time what could become almost civil war. Management must act.

    This thread is now far removed from what the OP intended
    In my experience, there's a big chunk of inspectors that like to reject work to show they've "earn't their money today".
    And the lazy ones - no, they're just so damn slow. They don't pass bad products because that will come back on them.
    And if ever questioned about their speed, the answer is they're being "thorough".
    The old saying "if you can't do it, then view it" is accurate for probably 1/3rd of the "viewers" i've worked with.

    Edit - I've just noticed Seymores post has been edited.
    President Xi would be proud...

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    Quote Originally Posted by SeymourDumore View Post
    To the OP, this is one option: Rotary Thread Inspection Tool | Thread Check

    Or, if you care to take it the next - next level, then these: https://www.johnsongage.com/wp-conte...ries-GJ-GJ.pdf
    Sorry. My internet acted weird and I don't know what happened. I hope this is more correct.

    The gauges in the first link certainly look excellent for small mass produced threads.

    The gauges in the second link look as if they are more for larger internal threads.

    Certainly interesting options for those mass producing internal threads and probably solve the OPs issue with torque.

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    Quote Originally Posted by Gordon B. Clarke View Post
    Sorry. My internet acted weird and I don't know what happened. I hope this is more correct.

    The gauges in the first link certainly look excellent for small mass produced threads.

    The gauges in the second link look as if they are more for larger internal threads.

    Certainly interesting options for those mass producing internal threads and probably solve the OPs issue with torque.
    Yes, the first one is for larger volume, probably sampling-type inspections, or perhaps mmachine-side quick checks by the operators.
    The second ones however go as small as .190 ( #10 ), or M5 in metric.
    I have a .250-28, .500-20 and a 1.000-20 UNJF set of pitch and functional.
    May be incorrect on the lower limit, but P&W requires all internal threads above 1/4" to be dimensionally inspected.
    IOW: Go/No-go plug gage final inspection is insufficient.

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    I've definitely met misguided inspectors. If they get beat up for passing bad parts they start to consider any uncertain situation bad, which sometimes involves too much force on a no-go gauge. Supervision or management beats them up for poor yield and suddenly they find a way to show a pass if there is one. More an issue in high volume production and less an issue in low volume situations where the inspector may be more skilled/empowered.
    The topic did get me curious though, is there a typical way to measure surface roughness on internal (or external) threads? What would this define? I've definitely experienced both fasteners that go in "rough" but still free, and others that are silky smooth. Mind you, using torque only is a poor way to get consistent preload, and it changes each time a threaded fastener is installed, but there must be a way to measure this "smoothness" for those who need it.

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    Quote Originally Posted by jccaclimber View Post
    .....
    The topic did get me curious though, is there a typical way to measure surface roughness on internal (or external) threads? What would this define? I've definitely experienced both fasteners that go in "rough" but still free, and others that are silky smooth. Mind you, using torque only is a poor way to get consistent preload, and it changes each time a threaded fastener is installed, but there must be a way to measure this "smoothness" for those who need it.
    Good thinking. And maybe a can or worms best left closed.
    Surface finish and contact area can affect torque or feel a lot along with lube.
    I know of very few people who evaluate or measure actual surface finish on a threaded working surface.
    Mostly it seems to be "looks nice".
    There is a big rabbit hole just waiting for someone to dive in and never come out of.
    Not just surface finish but geometry matches and contact area or points....
    Two mating and force loaded parts.
    Maybe why some stuff is done by bolt stretch and not input torque.
    Is a ground thread in the bolt and nut "bettter" than standard? It will feel nicer and smooth during assembly.
    On a spindle nut you will blue and hand work the back face as that may matter to the bearings.

    Yes, in the auto world you section and check the finish Ra. Here there is money to spend as an oops is mega bucks.
    You do not want a recall or field failures for some threaded hole that was rough on finish and failed later due to all sorts of things.
    Bob

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    Certainly not all posts but what I'm getting from several posts is that how good an inspector is varies very much from place to place.

    What I look for in a good inspector is several things but probably the most important is experience. He knows the product and is respected. Respect means he can also talk to those making the parts in the same "language".

    Wage is also important as if he or she earns less than those manufacturing then he'll/she'll always be regarded as "second rate". The employer is after all expecting the inspector to make important and critical decisions. A bad inspector could easily cost the company more than the machinist.

    The machinists I dislike are those that think the quality of what they make is the inspector's job and the inspectors I dislike are those that don't really know what they are doing. Dealing with that type of thing is why mangers get paid more than others. If they don't then they shouldn't "manage".

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    One place I worked at years ago, if the inspector didn't get the plug or ring gage to screw on, they would beat on the gage handle or on the OD of the ring gage to get it to go. Always blamed it on fine burrs on the threads. Yeah, right. Later, when they got a real OA engineer on board and saw what was going on, scrapped a boat load of gages that ware out according to the new spec. Speaking of specs, I created specifications for the manufacture of gages for in house use, and the program of keeping the gages in spec. These were "soft" gages we used. Got to remember, this is the way the oilfield did things before the days of Gagemaker. Oh, don't get me started on Gagemaker!!! Ken

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    Quote Originally Posted by 4GSR View Post
    One place I worked at years ago, if the inspector didn't get the plug or ring gage to screw on, they would beat on the gage handle or on the OD of the ring gage to get it to go. Always blamed it on fine burrs on the threads. Yeah, right.
    A place I worked at had a guy who did exactly that as well. Same reasoning.

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    Quote Originally Posted by 4GSR View Post
    Got to remember, this is the way the oilfield did things before the days of Gagemaker. Oh, don't get me started on Gagemaker!!! Ken
    That gets my curiosity. In your opinion is Gagemaker good or not so good? I believe they are expensive.

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    Quote Originally Posted by Gordon B. Clarke View Post
    That gets my curiosity. In your opinion is Gagemaker good or not so good? I believe they are expensive.
    Gagemaker is nice and for most applications good. Ah yeah, expensive!! But compared to a tool room full of plug and ring gages, cheap! To do the full range of threads, Vee, Acme, Stub Acme, Metric, not including tapered threads for oilfield connections, You're going to spend a minimum of $25-35K to get started. This would let you measure pitch diameters of threads from about 1-1/2" up to around 8-10". Larger instruments can get you up to around 20" and more. It's all about how much you want to spend. Oh, yeah, you almost have to buy the "Mic Track" to set the gages to. Of course, the MicTrack is also used to calibrate all of your shop micrometers and calipers with. It measures in 50 millionth increments! And guaranteed too! So doing that, you really don't need gage block set on hand as your "standard" for the shop to calibrate to.
    Getting back to the GM instruments for checking threads with. The biggest problem with measuring PD is on Acme and especially Stub Acme threads, their thread rolls they use can bottom out in the thread roots of the manufactured threads giving you a false reading. Seen a lot of bad parts get passed because of this. The threads look thin, especially on the comparator, and checked with thread wires that did not bottom out in the thread roots as being out of tolerance on the PD.
    GM did go in and somewhat fixed the problem after being threaten with a law suit over their equipment. IMO still not fully correct. But the problem with measuring Acme and Stub Acme threads, goes way back to our pioneers who developed the ANSI standards on these threads. There's specific requirements of plug and ring gages that are not proper for checking manufactured threads with and probably has caused many parts to be out of tolerance on the PD's because of this that needs fixing. This is what GM followed designing their gauging system to. And I'm way down in the deep hole not ever seeing daylight to voice my opinion to get people in the ivory tower to understand where I am coming from on this, to get the standard revised, to correct this problem.
    Ken

    Edit: I'm by no way an expert in threads but I'm very knowledgeable of threads and know what I'm saying. If that makes any sense to anyone. Ken

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    I try to keep an open mind on the many different types of gaging systems out there that are available for checking PD of threads. There are many advantages and disadvantages to everyone's system being offered out there including Gagemaker. And I don't have a favorite one to use per say. Good old thread wires and the easily obtainable thread mics with interchangeable anvils are my "go to" to use.

    As far surface finish on the thread flanks, mirror finish is ideal but not practical to must of us. My method of checking is, if the flanks look nice, no thread chatter, no tool marks, at least a 125 finish, 63 preferred, yeah try to check that with a proflorter, I consider it good. It's a visual check in my book.
    Ken

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    Quote Originally Posted by 4GSR View Post
    One place I worked at years ago, if the inspector didn't get the plug or ring gage to screw on, they would beat on the gage handle or on the OD of the ring gage to get it to go. Always blamed it on fine burrs on the threads.......
    You should see what production people trying hard to ship parts do with spline gauges...
    No, no, no you are using the gage ring as a broach....I know the SWI says this must fit. Hammering it on on off does not count.
    The first time I saw this I just freaked. I walked up and said "what the hell are you doing?" in a not nice voice. I'm all set to write this guy up.
    My worker is shocked so I call the crew together. My people tell me "We do all the time". I was floored.
    I do sure as ever understand why they were doing it and no other super and maybe above on the manufacturing side seemed to care.
    Despite all the new cares about in spec or quality nowadays the "can we ship it" still rules.
    Bob

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