Harold,
I have gages for measuring thread pitch because they came with my tap and die set. Obviously, they can't be used to measure pitch diameter directly. But if a correctly formed thread is cut on a known diameter cylinder, I would hardly consider trying to determine the pitch diameter of the thread as "perverse", especially if the thread form is a sharp V.
It's hard to argue the point in principle, len, it really is. But in the real world, where one has to perform under the scrutiny of QC, you quickly discover that the theory doesn't work. I can visually check a thread that close, no gage needed.
Did you take note of my statement about the relatively narrow thread pitch tolerance? Small threads can be only a couple thou. The human eye can't discern anything less than about .003", assuming you have good eyesight.. How is your gage going to help you?
I've been in the shop for over 45 years and have seen it all. What my time there has taught me is that you take nothing for granted. We measure so we know where we are. There are times when that may not be necessary, and I'm the first to admit to that fact. It can be true, even of threads. However, it is poor practice.
There's a little method in my madness, part of which is in defense of my years of struggling to achieve a level of excellence on the machine of which I'm very proud. In fact, it was an experience with what I might call a friend that turned me into a raving maniac that you see today. This person, a self taught machinist, who had worked as an iron worker (structural) and had changed to jewelry manufacturing, was engaged in building a small fixture for his table top CNC mill, with which he was machining waxes for investment casting. He had no clue how to find center, so his indexing fixture had eccentricity problems. When I tried to explain to him how he could locate dead center, he refused to listen to advice that would have enriched him from that day forward. In his mind, it was not important, and to have listened to one that also claimed to be a machinist might just have been an admission to himself that he, maybe, wasn't one. Perhaps that's what some guys suffer with. Maybe they want to see themselves as the equal of the guy that has done it for years, secure in the knowledge that any damned fool can be a machinist.
Well, that's true. Any damned fool can be. But it takes someone with intelligence enough to know and understand that which is important and to know when and how to apply it to be a good one. Hacks are a dime a dozen, and even show up in the job shops, where they don't usually last long.
So then, my purpose here. I am doing my level best to have the reader understand that there are ways to do it right. Also to discern the difference, and why. I don't mind telling you that I am highly offended when someone comes along that doesn't have a clue and assumes that because they do something in a slip-shod manner, it becomes the way to do a job, and worse, they try to pass it off as the standard. A perfect example of the blind leading the lame.
It seems that those of us that have spent our lives perfecting a skill are treated as their equal. Anything we may have to say that doesn't comply with their preconceived notions becomes, somehow, irrelevent.
Lets put this shoe on the other foot, len. I have no clue what you've done in your life, how you made your living, whether you were (are) a well educated professional or a blue collar type, but lets assume you are a physician. How would you perceive a guy that insisted that scrubbing was unnecessary, that operating with a rusty blade was fine, so long as you could saw your way through the tissues, and anyone that can hold a knife can do surgery. If you stepped in with your expertise and tried to explain to this person that, while it could work that way, that it is not the accepted practice and there are other ways that offer more safety and likelihood of success, he looked for every conceivable way and reason to continue the course, secure in the knowledge that it didn't matter. That's what it looks like to me when someone does everything in their power to avoid doing it right, and expects a pat on the head for their cleverness. You want me to agree with you? Come up to the standard, don't insist on me lowering the bar. I can't afford it. More importently, I
know better!
As I said, the method you choose has no bearing on me, nor my self image. It reflects strictly on you. You are the one that will use and live with your decisions. You, and only you, will make the decision to part with $15 to buy a set of p-d wires that will serve you reasonably well.
Noone is disagreeing with you about the "proper" methods for generating and measuring accurate threads, but you seem to have trouble accepting the fact that some of us aren't striving for the perfection that you preach. Sometimes "good enough" is really good enough. And yes, sometimes you have to use a chisel to kn! ock out a stubborn nut, not because you like to do it that way, but because you either don't have the $25 to spend on a 36mm socket, or because you would rather spend it on something else.
Guilty as charged! And I make no secret of it. I have little tolerance for poor craftsmanship, nor do I suffer fools gladly.
I've run machines long enough, and have worked around enough hacks, to know that it takes no longer to do things right than it does to do them wrong, and I'm sick to death of following up fools that refuse to do it right, but want someone to bail out their miserable asses when they fail. I do my level best to have people learn the principles and to do it right. Those that refuse I have little interest in supporting.
Early in my apprenticeship I was going to be fired for various reasons, including my immature attitude. I was only 18. I had one person show a personal interest in me, who convinced upper level management to extend my probationary period and to allow him to work with me. He took me aside and taught me, over a period of almost a year, to do it right, take it slow, check twice, cut once, etc., etc.. He made a machinist out of nothing. A literal silk purse out of a sow's ear.
This person taught me exactly that which I am trying to teach others, that there is only one way to learn things, and that is the proper way. With skill and knowledge, one can then make intelligent decisions about what will work and what won't. It's better to know how to walk before attempting to run, yes?
Sounds like you would have made a poor hippie. [img]/ubb/images/graemlins/smirk.gif"%20alt="[/img]
Yep! In spite of my over shoulder length hair, beard that has not been shaved off since 1964, my ear ring and my very outspoken independence, I'm not much of a hippie. I conform with the rules, drive the speed limit (I really do!) and I don't do drugs. [img]/ubb/images/graemlins/smile.gif"%20alt="[/img] I have been known to sip a bit of single malt, though. I like mine with water, heavy ice. [img]/ubb/images/graemlins/wink.gif"%20alt="[/img]
I make one hell of a good beatnik, though. [img]/ubb/images/graemlins/grin.gif"%20alt="[/img] (I'm saying this as I listen to some Errol Garner!)
Harold
