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  • Endmill
    replied
    I agree that there is too much focus on feed rates and cutter speed, clearance and rake angles and on the merits of carbide vs HHS vs ceramic etc.

    These parameters may be of economic importance in fine tuning an automated camshaft factory where the expertise is presumably built into the system, and the selling price is based on projected return on capital investment.

    Some of the hype may also be attemts to market marginal product improvements or oversell expertise. Accuracy and precision are also hyped to habit forming excess. I don't need 0.001 tolerance for bolt holes!

    Items are sold by the piece, but labor is purchased by the hour and profits are highest where wages are lowest. (The correlary is that given sufficiently low wages anyone can make a profit.) (The Chinese are still making a profit, but the Japanese are not.)

    The pressure is obviously on time, but since each job is likely to be different, a set of general default values will likely be more cost effective than exhaustive analysis, or continually resetting machine parameters. This is what an experienced hand does automatically.

    The problem is that someone improperly bids a job, and then trys to put a time monkey on the machinist. After six meetings they decide that the cost overrun was due to too slow a feed rate.

    Most of my life has been spent doing and managing R&D. An expert is someone who has made all possible mistakes but learned from them. Correlary: The height of stupidity is to keep repeating the same thing and expecting a different outcome.

    Procedure or technique or work break down is of more significance than setting parameters, and anything that works well is correct.

    I generally build something in my mind before I ever start work. I break the task down into steps, and mentally complete each one, and then write myself a short letter describing each of the steps as I visualized them with the projected outcome, and any possible problems. (For something new, I may make a baseline model, and do modeling to convince myself that what is proposed will work.) You may identify steps which you don't have much experience with, such as using a special tool, in which case you should validate your methods on some scrap.
    Sketches and dimensions come next, along with materials, needed tools and fixtures. Parameters are added last. (Your outline could include a list of critical dimensions and a place for your final measurements.)

    Even if one starts with a set of prints, you still need to match these up with your specific tools, available materials and specific tasks, and making a plan or outline is worthwhile. You then know what sizes of drills, counter-bores, taps, lathe tools etc are need, along with other supplies. Also you can check for consistency in dimensions, drafting errors, and omissions, and if necessary, make some phone calls to clear up the unclear.

    On large work (which I don't do), you will know when you need some extra help or lifting equipment. There is no excuse for dropping a lathe chuck on the ways, or drilling into a table.

    I try to estimate the needed time for each step before I start, and leave some space for actual times. You can then set up your work day, lunch or beer break, and stop work when you are overly tired or stressed out and more prone to errors.

    The plan is basically for your benefit, as a self management tool, but it obviously has political uses if you are an employee. (A collection of these, with some finalized details which compare your projections to actuals is potentially very valuable to management in submitting bids for similar work or in proposal preparation.) Also take some pictures if you can of your setups and finished product(s) This is good for possible HSM articles, or future job hunting if your talents are unappreciated.

    I am conservative in most tool settings.
    Once in a while I change the speed of my drill press, but I haven't changed the milling machine from its mid-range setting in 10 years. Same thing with the metal band-saw which is on the slowest setting. I cut 8" sections of stainless without a problem as well as aluminum. What I loose in time I save in blades.
    End of Rant
    Bob

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  • docsteve66
    replied
    I mentioned that i no longer made things to last forever- maybe its a case of better judgement today.
    The Motorhome shed (10 years old) will not last another 10 years, but i just put a new alternator on tractor (tractor is probaly 50 years old (A massey Ferguson TO 30) but it will last another 50- at least more than I will last. It will go to son in law and hopefully Gson. The modified bracket and alternator will last till the tires rot off or the wheels rust out. 20 years ago, the welds would have been ground, edges smoooth and would not have lasted ten minutes longer as the result ofthe extra work work. maybe foolish pride has flown at last!!!!
    Steve

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  • docsteve66
    replied
    then there is "singuluar rectal opticalitus"- a condition suffered by those who have ONLY 20/20 hindsight

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  • lynnl
    replied
    Another of my favorite expressions is a 'recto-cranial inversion'. (see also "Political Leaders")

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  • darryl
    replied
    Spinach, mmm. ok Know what's tastier than spinach? Stinging nettles. Pick them properly, and you don't need gloves. Use gloves, pick a peck, boil 'em up and yummm. I hate soap.
    Tapestry of expletives, I like that. I imagine we've all woven one of those at one time or another.

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  • Thrud
    replied
    Jaymo:
    At least it(soap) tastes better than spinach - I hate Spinach.

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  • Jaymo
    replied
    Thrud--when I got to that stage, my mom would just peel an onion and stick it in my mouth. She knew that I coudn't stand onions. It was much worse than soap. At least she could have cut them into rings and fried them first. A little ketchup wouldn't have hurt, either.

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  • Thrud
    replied
    lynnl:
    And after a while you get used to the taste of bars of soap - that really got my mom pissed off - she didn't know what to do then, she was so flustered and my dad was laughing...

    Funny show. A true classic.

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  • Spin Doctor
    replied
    But Lynnl' YOu'll shoot youe Eye out!

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  • lynnl
    replied
    Steve, I gotta confess, I sto.. 'er borrowed that expression from the movie "A Christmas Story". It was about a little boy growing up in Gary Ind. who wanted a BB gun for Christmas. It's narrated by the boy recalling that period later as an adult. He said of his father: "...profanity was his true medium. ... he worked in profanity like other artists might work in oils or clay..."
    One of the best movies for the holiday season, especially for guys, tho my wife and daughters like it too.

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  • docsteve66
    replied
    Lynn : RE: " I wove a tapestry of expletives ......"> I sure hope that phrase is not copywrited ot protected in some way. I intend to use it one day!!!
    Steve
    Problem is my cussing buddies dont know tapestry from tape, expletives from explainations and the people who do know are ones that I say, "I really should have thought more before trying to do that".

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  • lynnl
    replied
    John S., those were funny! I'm imagining some good impressionist doing that first line in Dubba Ya's voice. (George DubbaYa's that is. or maybe Al Gore's)

    Thrud, your last post brings back a painful memory. I did that very thing. Whacked it so hard I cried. Let project rest for 2 or 3 weeks, then resumed EXACTLY where I left off. (Same hammer, same nail in same hole of same board ... also same thumb!) That time I didn't cry, I wove a tapestry of expletives that's probably still hanging in the air today.

    [This message has been edited by lynnl (edited 02-16-2003).]

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  • Thrud
    replied
    darryl:
    Sure! Sometimes you feel so good after a great meal you are full of piss and vinegar and everything just clicks. Other times, you turn the feed down and go whack your thumb with a hammer on the bench - accidently, twice.

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  • darryl
    replied
    I'm wondering about cutting speed, does it change depending on what you had for dinner?

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  • Thrud
    replied
    Steve
    If I have learned anything in my many brushes with death is as long as the world is giving you sh*t and abuse - you are still alive! Worry about it when you start to feel really, really, "special".

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