planimeter and integrator

Discussion in 'Boat Design' started by SamSam, Nov 11, 2009.

  1. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    The other thread moved to 'marketplace' where it won't be seen again, but it inspired me to finally scan this from an old engineering pocketbook of my Dad's. It seems a person can make one any size they want and put the dimensions of it into the formula. The accuracy might be loose, but maybe close enough, considering the cost. Click on the thumbnail and then the picture to make them big enough to be readable.
     

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  2. dskira

    dskira Previous Member

    I use mechanical integrator and planimeter for now forty years and the accuracy is pretty good, providing you take care of them, and know them well.
    About the integrator, it is extremely fast. But the machine is a little cumbersone.
    Very useful for stabilty calculation, fast and accurate.
    Of course this methode is pre-computer style of working.
    A integrator is almost impossible to find now, the only one who can built one Is Lasico, and I am not sure they continue doing them, and for the planimeter, the best is the German Haff, and also the Lasico in Los Angeles.
    A second hand planimeter (which is not a good idea to buy) goes between $50 and $200, depending. Of course an original Amsler can go higher for collectors, like a $1000.
    Cheers
    Daniel
     
  3. C.Rödiger
    Joined: Oct 2008
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    Location: Bremen, Germany

    C.Rödiger New Member

    Me too.
    I do too much work at the computer, so at home I still do it the old way. My Planimeter is from Ott, and although second-hand, it is still as accurate as it says in the innitial callibrating.
    What you say about the Integrator is most interesting, though.
    They are not as inaccessible as you say, 14 month ago, an Amsler No.2 went on E-bay for GBP 690.- and this spring a modern Amsler (ca. 1960) went for about US$150,-(shipping and toll duties would have doubled the price, so I dropped out...:mad: ) both without the rail, of course...

    And that`s exactly the point: I do have an Amsler No.1 without the rail. I want to have this made for me, so I can use it again, but I do not have the section of this rail.
    I asked at the "Deutsches Museum", and of course, they do have one of those rails, but they have neither the time nor the man to measure it for me.
    The two different lenghts I got from the K&E catalogues on the internet but not the section.
    So, is there anyone out there who can provide me with a drawing(.pdf or .dwg) of this rail? As it was made on the continent, it was probably made in metric measure.

    Let`s keep the knowledge how to work these alive.

    Cheerio,

    Carsten
     
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  4. dskira

    dskira Previous Member

    Carsten for the rail, you can take a flat aluminim bar to the suitable length and go to a steel fabricator and with a router he can put the grove in the flat bar. Do you have the two reference guide? these are the most importants. If you don't have them, you have to go that way: The lenght of of the guides is exactly the legth from the groove to the pivoting point of the tracing arm.
    Then make some trail with round sections.
    I am glad you can find some in good condition at good prices.
    My first was an Amsler (don't have it when moving to the US), and then I have two built for me by Lasico.
    As I said I use them all the time for now forty years, never fail, never a problem.
    Carsten I am glad to know some one who apreciates these instruments
    By the way just of curiosity, are you a naval architect? Or do you use the instrument for other purposes?
    Cheers
    Daniel
     
  5. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Who was trying to sell an integrator without a beam on E-Bay?...We (my office) lost ours (most likely snagged by a retiree) when they closed down Mare Island Naval Shipyard and shipped us up to Puget Sound, but we still have an eight-foot beam for one. I'll see if I can get the maker and dimensions (Swiss made SS beam with a single V groove). Makes a great plan weight.. though I have had to stop people using it for a straight edge or cutter guide :rolleyes:

    For those of us that started engineering BPC, I think we got pretty proficient at using the mechanical tools and hand drafting. And hand drafting is still superior for lines planes IMHO. It suprises me how long it takes one of the new engineers to get a solid model drawing out to make a small structural detail. Nice if you ever have to change something on an existing model, or use it as a block to build a larger model, but for a one-off to get the existing shell modified when you have to lift the offsets...shrug...

    Anyway, about 20 years ago I was handed a wrapped birthday present by my sister-in-law. She had this big grin on the face and said "You'll never guess what it is." I hefted it for a moment and said "It's a planimeter...most likely a K&E with an adjustable arm"...(There are only a few things that size and weight and after you handle them a lot you just know). I was right of course, she had recieved it when her grandfather died and the family did a "name-it-and-claim-it" He had been an engineer for North American Aircraft down in LA, and I later got all his curves, but they are celliod and too fragile to use.
     

  6. C.Rödiger
    Joined: Oct 2008
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    Location: Bremen, Germany

    C.Rödiger New Member

    Hello Daniel,
    Thanks, but I would prefer to use steel, aluminium is to light imho. Judging from Uffa Fox`Second Book, the section of this rail is 80x15, with a lenght of 1,5m ,giving a weight of about 15kg which should make it immobile.
    I do have the distance pieces, but that makes my problem: the ends of these parts have a semicircular section, the wheels of the integrator have triangular sections and from what I gather from other sources (Johow-Foerster "Hilfsbuch für den Schiffbau") the grove is an inverted "T".:confused:
    And yes, I am a naval Architect.
    Hello Jehardiman,
    Yes hand-drafting is about 1.5 times faster than CAD, but this is only true for the innitial construction. Changing (and most construction is just that...) is much faster on a computer...
    By the way, it was a curious auction on E-bay, as the seller could not tell anything about the integrator, and he said he didn`t have the rail. Everything else he sold where spare parts for heavy haulage or heavy, near-scrap machine parts. And the integrator was not labled as such, nor even as a planimeter, but as "curious scientific instrument" or some such.
    And is it that wrong to use an integrator rail as a straightedge for a cutter?
    The grove must remain absolutely straight, but a nick or a scratch on the far side of the rail has no influence on this imho.
    In days gone by you used the lower part of the T-square as a guide to cut the drawings, too, and a wooden T-square is much more fragile than this steel bar.
    You cannot use the scale as a straightedge for a cutter, neither can you use the drawing-straightedge, but sometimes you do need a long straight cut...

    I have been looking around for a maker who can mill me a rail in this size (1,5m) with the precision I want (less than 1/100th mm), so far I have found one and he will not be cheap...:(

    Cheerio,
    carsten
     
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