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Thread: Set of Copenhagen curves (ship's curves) on eBay now

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    Default Set of Copenhagen curves (ship's curves) on eBay now

    Usual disclaimer: no connection to the seller here. I've got a set or I'd be bidding myself. This looks to be a very "complete" set, less one or two curves... "complete" sets vary in number. Some curves out of the total number called "Copenhagen curves" are quite redundant. This looks to be one of the sets sold by McNaughton to its naval architecture students back in the 70's. It also has a nice fitted case to store the curves. Copenhagen curves are invaluable for designing boats. (Ducks and battens are, too. Their applications overlap, but neither covers all the bases completely.) I thought I'd pass this along in case anybody on the forum is lusting after a set. The bidding is already hot and the price is up to $96 with a couple of days to go.

    Although a handful of shapes can still be obtained from manufacturers on line, at this time no one appears to still manufacture and offer for sale a complete set of Copenhagen curves new. They are virtually unobtainable except very, very occasionally on eBay, and then almost always only in partial sets. (They were always very expensive... I know, they don't look it, but they always were a specialty item and often hand finished.) Amazingly, two fairly complete sets just came up at the same time on eBay, perhaps from the same source. The first, a partial set, was immediately snapped up on a "best offer basis" for $180. (Somebody got a good deal... even though the set wasn't as complete as this one.) Another sold last month, the first offered in a long time. It was a comoplete Dietzgen set, also in a mahogany case. It went for $232.50. I'd feel safe in saying that there's no way of telling when another complete set might be offered, but I wouldn't be surprised if only one comes along every couple of years on average. No other complete or near complete cased sets have come up in a couple of years. So, if you really want them, you know the drill: Decide the absolute most you would pay (if it were me, maybe $300) and "snipe" the billing by posting your highest bid as an "automatic bid" at the very last second in the bidding (maybe ten seconds before expiration, or use a "sniping" program service) and hope you beat all the other "snipers." Don't waste your time bidding and bidding. The "snipers' will beat you every time. Let eBay automatically increase your bids for you electronically. On an item like this, which will be in very high demand (already 16 bids on it by "amateur" bidders) you will likely see a huge jump between the incremental bids just before the time expires and the sale price due to 'snipers" tossing in much higher bids.

    From the listing: http://www.ebay.com/itm/301489207625...%3AMEBIDX%3AIT


    "This is the most complete set of drawing curves one should need for yacht and small boat design. Originally supplied through a source in Maine around 1998. These have drawn a few yachts and workboats so they are used. Though unbranded they are mostly all marked with shape number and the USA notation. The were carefully maintained and in serviceable condition and really in very nice shape. They where lightly used but as like many others, the owner went into computer drawing as required by his employer and had enough duplicates to handle day to day jobs. So this complete set was redundant. The wooden box is unlined with plated latches and hinges. Lid closes and latches easily. Not certain the wood but it's sealed and attractive.

    The following are the supplied curve shapes:

    31/33/34/35/36/37/38/39/40/41/42/43/44/45/46/47/48/49/50/53/54/55/56/57/58/59/60/62/64/68/71/80/83/84/86/89/91/92/97/100/101/102/103/104/107/108/109/114/119/120/121/128/136/150/

    There may be a couple of extra general purpose curves in there too. Little bit of a bonus for you."











    Original Kueffel and Esser Copenhagen curves with numbering designations:


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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    One of those ideal objects for the home 3D printer ... if it was accurate enough.
    Await dreams, loves, life; | There is always tomorrow. | Until there is not.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by htom View Post
    One of those ideal objects for the home 3D printer ... if it was accurate enough.
    Gee, I never thought of a 3D printer. Maybe a plasma cutter might work, too. Might be a nice little retirement business for somebody.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    dang bob, i was gonna bid on those tomorrow. . .
    Simpler is better, except when complicated looks really cool.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Or a numerically controlled water jet cutter.
    Await dreams, loves, life; | There is always tomorrow. | Until there is not.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now


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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Six months ago I would have jumped at these.

    Under your tutelage, Bob, I've figured out that I like ducks and splines.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by keyhavenpotterer View Post
    WOW! A set of railroad curves with Brunel's company logo on them brought $41,207 and we don't even know if they were his own personal curves or just stamped with his office's logo. (He had to have lots of draftsmen working for him.) Some of these drafting instruments bring amazing prices on the collector's market. Right now, it's "get it while you can," even for the good 20th century "user" instruments, because CAD has knocked the bottom out of the manual mechanical drawing trade and there isn't enough demand to warrant anybody making the good stuff anymore.` Keuffel and Esser and Dietzgen no longer are around making the top of the line US marked instruments and even the few remaining European manufacturers are only offering what would have pretty much been considered junk by any professional draftsman fifty to seventy-five years ago. There's nobody I know of making the hand-fitted (and thus highly accurate) instruments that used to be offered by K+E in their "Paragon" line or Dietzgen in their "Gem Union" line, all of which were fashioned by German and Swiss instrument makers.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Jammersix View Post
    Six months ago I would have jumped at these.

    Under your tutelage, Bob, I've figured out that I like ducks and splines.
    Ducks and spines work fine, except that you have to have your own "eye" for a fair curve. Curve templates are accurate every time and were often much faster to use for a skilled pro, for whom time was money. Curve templates are also much easier to use when the curves get tight. Ducks and battens get tougher to use when you are drawing sections and things like that. Besides, they are just one of those things that you don't need but are just a lot of fun to have. (Like wives, perhaps.)
    Last edited by Bob Cleek; 01-23-2015 at 10:40 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Paul Pless View Post
    dang bob, i was gonna bid on those tomorrow. . .
    Go for it! Go for it!

    BTW, doesn't your lady work in automotive design? Automotive and aircraft designers also used ship's curves back in the days before CAD. If so, tell her to scout out the dusty junk in the back of the storeroom a the office. She might just find a set or two they haven't thrown out. Worth a look, at least.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Bob, can I ask, is there written information for the use of ships curves that explains there best use as a tool. Is it a case of grabbing the one you like the look of or seems most suitable, or is there written information that once understood makes the many different curves easy to understand or segregate into optimal uses? They are a tool, but beyond them as objects, is there information anywhere to the best use or application, given that there are so many.

    Ed

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Ed,
    The picture Bob posted comes from Chappelle's Yacht Design and Planning (I think). I don't have a copy to hand but he's bound to say more on the subject.

    Shouldn't be rocket science to produce on a laser cutter. Most Design and Technology departments in schools in the UK now have one to eliminate the need for students to learn to use their hands for anything other than pressing keys.

    St.John

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by keyhavenpotterer View Post
    Bob, can I ask, is there written information for the use of ships curves that explains there best use as a tool. Is it a case of grabbing the one you like the look of or seems most suitable, or is there written information that once understood makes the many different curves easy to understand or segregate into optimal uses? They are a tool, but beyond them as objects, is there information anywhere to the best use or application, given that there are so many.

    Ed

    Yes and no. Using them as a simple template for a complete shape is only a small part of their value. There's more to it. They are used either by picking the shape you like, perhaps picking one of the "sweeps" (the large slightly curved ones) to draw a sheerline, or as a French curve would be properly used, by matching the curve, or series of curves to the points on a plotted curve. There is some data on using French curves in some mechanical drawing texts, but it is very simple, actually. Here's a couple of fairly good explanations: http://engineeringtraining.tpub.com/...s/14069_92.htm http://jep-s.blogspot.com/2010/07/french-curve.html A general overview of technical drawing instruments can be found at http://en.wikipedia.org/wiki/Technical_drawing_tools

    Ship's and French curves aren't just templates for drawing only the curve that's on the edge of the template, but when used in combination, for drawing any fair curve. It's all about the fairness of the curve developed. The shapes are mathematically related to each other so that curves properly drawn with ship's or French curves will be fair. By using a curve or combination of curves whose edges touch plotted points on a desired curve (and properly overlap previously plotted points used as the curve is progressively drawn,) any curve can be fairly drawn. The value of drafting curves is the fairness and flexibility that they make possible. Even today, with CAD (disclaimer: I'm not a CAD user,) such fair curves as can easily be generated with drafting curves are only possible to generate digitally with the most sophisticated (and expensive) CAD programs and the training to use them. Some draftsmen whose careers have overlapped the transition from manual to digital drafting say they can manually draft irregular curves faster on the board than on the screen, although as the CAD technology continues to evolve, I expect that will not remain the case.

    A picture is worth a thousand words:






    Perhaps not surprisingly in this day and age, there's nothing on Youtube that will do you any good. The tutorials all seem to address using curves as simple templates, as in the first method of use described in the paragraph above. That limits the value of drafting curves to "what you see is what you get" in terms of the curve produced. Obviously, in drawing boats, we can't be limited only to the various curve templates we might have on hand! Actually, there are a number of classically recognized curve sets, now extremely hard to come by. You can find them pictured in old drafting instrument catalogs. One set is the "Copenhagen" ship's curve set. (There are other, older and more obscure "ship's curve" sets which are now extremely rare. The "Copenhagen" set became the standard in the 20th Century.) There is nothing "shippy" about "ship's curves" except that they are the set of curves most useful in naval architecture and so sold in sets as such. (They were also used by automotive and aeronautical designers.) "French curves" are another set of general use curves which don't contain the long "sweep" curves necessary naval drafting. They are very useful to the naval architect nonetheless for tighter curves. Ship's curves and French curves are "irregular" curves, meaning that they are curves that do not have a single fixed radius. There are also "railroad curves" and "highway curves" which are used in laying out railroads and highways in civil engineering. These are "regular" curves which have fixed radii. (There is a difference between the two. The arc of railroad curves describe each curve in terms of 100' of chord across the circle, while highway curves describe the arc of each curve in terms of 100' of curve.) Regular curves are of limited use in naval architecture where regular curves rarely occur, but are useful in some instances, such as drawing the crown of decks and deckhouses, which varies as the sheer curves and beam width change at each station. This can be done with a regular drawing compass, but finding the radius of each crown segment at every station takes a lot more work than finding and laying down a fixed radius curve that fits across the span with the proper crown height.

    You can find a fairly decent text on technical drawing techniques and instruments at http://engineeringtraining.tpub.com/14069/ It has a section on French curves.

    The reason drafting curves are capable of generating fair curves is because they just aren't a collection of shape templates, but rather represent mathematically calculated shapes that relate to each other so that in use fairness is ensured. The shapes are segments of the Euler spiral or clothoid curve, or so I've read, but beyond that, I've no real understanding of what the hell those things really are. The mathematics involved is way beyond my pay grade, but here's an academic paper on it that perhaps somebody here who didn't sleep through trig and calculus like I did might find interesting. http://www.dgp.toronto.edu/~mccrae/p...aeSBIM2011.pdf

    You can find good pictures of all the different types of curves in the Keuffel and Esser catalog which can be found at https://archive.org/details/pricelistcatalog00keuf starting at pages 231 to 238.

    A full set of "modern" Copenhagen ship's curves produced until the mid 1970's or so, and which went extinct when CAD took over:



    The standard Copenhagen ship's curve set of shapes from the Keuffel and Esser catalog. The numbers on each are standardized with all manufacturers:



    A full set of either railroad or highway curves, also "modern:"



    And a nice set of French Curves:

    Last edited by Bob Cleek; 01-24-2015 at 06:22 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    I'm a black hair, Mary Ann man, not a blonde Ginger man.

    Like a lot of things connected with hand drafting, I'll throw this in: using ship's curves is simple, but it's not easy.

    The theory is simplicity itself to explain and understand, but look forward to smudged lines, unfair joints and lots of erasing while you practice and become even marginally proficient at drawing curves this way.

    Not that it's not a good method, quite the contrary, but it's a skilled task, and a high skill task at that. At least, in my opinion, after having spent a mere month playing with curves.



    Last edited by Jammersix; 01-24-2015 at 09:24 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    well there is a lot to be said for the old way
    Getting fair curves into MAXSURF or Rhino is driving me nuts, best to loft the lines full, fair them then take offsets and copy into rhino,
    Then you are sure the boat will look sweet
    CAD can use a hell of a lot of time, I miss the loft floor where I used to draw every floor, frame, gusset knee, full size
    And good threads on CAD in the forums?

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    The theory is simplicity itself to explain and understand, but look forward to smudged lines, unfair joints and lots of erasing while you practice and become even marginally proficient at drawing curves this way.
    No question about it. Practice is essential to mastering any skill. Fair joints take practice and care. Did you ever take mechanical drawing (drafting) in high school? When I was in high school in the sixties, it was one of those "easy A" courses for me. Boys took mechanical drawing and the girls took "home economics." I loved it. A few things were drummed into me and l haven't lost them. Cleanliness is next to Godliness. You have to be very neat, take your time and follow good procedure. (Wash hands frequently. Don't sharpen pencils over your board. Wipe your lead after sharpening. Clean the edges of your straightedges and curves frequently. Use the proper eraser and brush your work after erasing. Put tape or "spacer dots" under your straightedge or curve when inking so the ink won't run under the template. And so on.

    Erasing is part of the game. Unlike a lot of other uses for an eraser, their use in drafting isn't only about correcting mistakes. Your construction lines and so on are going to be erased. Little ticks and whatnot will be erased. You need the right paper (drafting vellum) and the right eraser. (The white vinyl ones Staedtler makes these days are great.) You also have to use the right lead. You want to do your drawing with a very hard lead (3H or 4H, some use harder) because it leaves little graphite on the work and is easily erased without smudging. Only when you have it all done like that, then you ink your final lines. Using the older ruling pens is an acquired skill, but technical pens (Koh-i-noor Rapidograph, etc.) are much easier to use and the newer porous tipped pens (Micron) are even easier, although their tips wear down rather quickly. (The different sized pens are for producing different weights of line, of course.)

    There's a lot of fascinating fun to have playing with this stuff. You can get a new set of technical pens on eBay for maybe twenty bucks if you are lucky.



    Or you can use a traditional ruling pen that comes with most older cased sets of drawing instruments or can be bought one-off:



    They take a bit of practice to use, too, of course:



    And for boats, where there will be a lot of curves to draw, you'd need an old fashioned pen specially designed to draw curves (yep... one for lines and one for curves.)
    The head of the curve pen swivels and the nib is curved, so as you draw, it follows the curve. This keeps the width of the line drawn the same size. The width is set by varying the spread of the nibs on these type of pens.

    If you want to draw perfectly parallel lines, like for rail caps and the like, you need one of these puppies. It's called a "railroad pen."



    I recently scored a real rarity:



    It's a Keuffel and Esser "Paragon" (their top line) "dotting pen." Cost me twenty-four bucks. Ivory handle, which screws off to reveal a "pricker" for tracing (you punch a little hole through the original drawing into the new one when tracing with paper that you can't see through. Made obsolete by the invention of the light table.) and the wheel picks up ink from inside (it opens up to fill) and draws a very fine dotted line. There are five other wheels stored in the nib assembly which can be swapped out to draw a variety of perfect broken lines: dots, dashes, dot-dot-dash, dash-dot-dash and so on. It's a lot of fun playing with the "tools of the trade" as well as fun drawing the things we do.

    Continued in next post:
    Last edited by Bob Cleek; 01-24-2015 at 10:55 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    As for erasing, get yourself one of each of these:





    You can pick up an electric eraser on eBay for as little as $15. The old 120 VAC ones are better than the new battery powered ones. More powerful and no batteries to always be replacing. Or, if you don't want to do that, get an "eraser stick" as shown in the picture. It is essential, however, to always use an eraser shield, the credit-card sized metal template that protects the surrounding work from being erased when you are erasing what's next to it. We'd catch hell if Mr. Dillon, our mechanical drawing teacher (and football coach... ain't it always that way!) ever caught us erasing without using a shield or wiping eraser dust off our board with the back of our hand instead of our brushes. (The electric erasers take the eraser stick refills sold for the manual eraser sticks. The 120 VAC electric erasers don't seem to be made anymore, though, so you have to snag them on eBay. They are very common.)

    Hope this info makes for less erasing hassles and more drafting fun!
    Last edited by Bob Cleek; 01-24-2015 at 10:58 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Thank you for that Bob and St.J. Great info.

    Bidded but didn't win them...set went for $326.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Bob Cleek View Post
    No question about it. Practice is essential to mastering any skill. Fair joints take practice and care. Did you ever take mechanical drawing (drafting) in high school? When I was in high school in the sixties, it was one of those "easy A" courses for me. Boys took mechanical drawing and the girls took "home economics." I loved it. A few things were drummed into me and l haven't lost them. Cleanliness is next to Godliness. You have to be very neat, take your time and follow good procedure. (Wash hands frequently. Don't sharpen pencils over your board. Wipe your lead after sharpening. Clean the edges of your straightedges and curves frequently. Use the proper eraser and brush your work after erasing. Put tape or "spacer dots" under your straightedge or curve when inking so the ink won't run under the template. And so on.

    Erasing is part of the game. Unlike a lot of other uses for an eraser, their use in drafting isn't only about correcting mistakes. Your construction lines and so on are going to be erased. Little ticks and whatnot will be erased. You need the right paper (drafting vellum) and the right eraser. (The white vinyl ones Staedtler makes these days are great.) You also have to use the right lead. You want to do your drawing with a very hard lead (3H or 4H, some use harder) because it leaves little graphite on the work and is easily erased without smudging. Only when you have it all done like that, then you ink your final lines. Using the older ruling pens is an acquired skill, but technical pens (Koh-i-noor Rapidograph, etc.) are much easier to use and the newer porous tipped pens (Micron) are even easier, although their tips wear down rather quickly. (The different sized pens are for producing different weights of line, of course.)

    There's a lot of fascinating fun to have playing with this stuff. You can get a new set of technical pens on eBay for maybe twenty bucks if you are lucky.



    Or you can use a traditional ruling pen that comes with most older cased sets of drawing instruments or can be bought one-off:



    They take a bit of practice to use, too, of course:



    And for boats, where there will be a lot of curves to draw, you'd need an old fashioned pen specially designed to draw curves (yep... one for lines and one for curves.)
    The head of the curve pen swivels and the nib is curved, so as you draw, it follows the curve. This keeps the width of the line drawn the same size. The width is set by varying the spread of the nibs on these type of pens.

    If you want to draw perfectly parallel lines, like for rail caps and the like, you need one of these puppies. It's called a "railroad pen."



    I recently scored a real rarity:



    It's a Keuffel and Esser "Paragon" (their top line) "dotting pen." Cost me twenty-four bucks. Ivory handle, which screws off to reveal a "pricker" for tracing (you punch a little hole through the original drawing into the new one when tracing with paper that you can't see through. Made obsolete by the invention of the light table.) and the wheel picks up ink from inside (it opens up to fill) and draws a very fine dotted line. There are five other wheels stored in the nib assembly which can be swapped out to draw a variety of perfect broken lines: dots, dashes, dot-dot-dash, dash-dot-dash and so on. It's a lot of fun playing with the "tools of the trade" as well as fun drawing the things we do.

    Continued in next post:
    All good stuff, but BoPET drafting film and polyester leads in something like the Pentel pencil are far less messy.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Yep, $326.52. Surprising how much demand there is for these things. You'd think somebody would be still making them. I guess it just doesn't pencil out for manufacturers. Manual drafting instruments are the buggy whips of our era, I guess.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Peerie Maa View Post
    All good stuff, but BoPET drafting film and polyester leads in something like the Pentel pencil are far less messy.
    True, although I find that the skinny .05 and .07 leads in them break so easily. I like the 2mm leads, myself. They can also be needle pointed, which is much harder to do with the thin leads. It's interesting to track the impact of the development of copying technology on drafting instruments. It took an inked drawing to get a good blueprint, but when other copying methods became available, everybody started doing finished drawing in darker pencil and all the old inking instruments started to become obsolete. Things like dotted line tape you could just stick on a drawing eliminated dotting pens. The design of compasses changed with center wheel adjustments which prevented the tendency to spread the legs when pressing harder to get a good impression with pencil. The "light touch" required for light pencil and ink was replaced with a more ham-fisted approach. In the last years of professional manual drafting, they started coming out with compasses that were purpose-built to hold technical pens. The really beautiful "jewelry grade" instruments, hand made and fitted of German silver were no more, replaced by ordinary stamped metal. It really was a lot like firearms. In WWI, they carried finely made Springfields that could drive a tack at 50 yards and 50 years later in Viet Nam, they were carrying "throw-away" plastic and stamped metal M-16's that were lighter and sprayed automatic fire all over the place. The M-16 is certainly the better infantry weapon on today's battlefield, but an old M-16 can't hold a candle to an old Springfield in terms of fit and finish and pride of ownership.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Bob Cleek View Post
    True, although I find that the skinny .05 and .07 leads in them break so easily. I like the 2mm leads, myself. They can also be needle pointed, which is much harder to do with the thin leads.
    Never occurred to me to point a .05 or a .03 lead.

    I figured you used them with no point, and you used one when you wanted a line .05 wide and the other when you wanted a line .03 wide. I figured not pointing them was the advantage of using them. Well, that and you can buy them at 7-11 at two in the morning.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Jammersix View Post
    Never occurred to me to point a .05 or a .03 lead.

    I figured you used them with no point, and you used one when you wanted a line .05 wide and the other when you wanted a line .03 wide. I figured not pointing them was the advantage of using them. Well, that and you can buy them at 7-11 at two in the morning.
    Yes, that's true. They are easy to come by (although the good professional quality ones won't be found at 7-11. There's a difference between the 2mm and the smaller leads. The 2mm is designed to always be needle pointed. You just spin the point in a purpose-made Tru-point lead pointer.

    Just to show some nice drafting, as well as the lead pointer:



    This is the ubiquitous cast iron model. Smaller plastic ones are currently available from Staedtler.



    A drafting pencil is properly rotated between the finger tips as a line is drawn. This keeps the point conical and pointed. A line drawn without rotating the pencil will result in a point that wears and flattens as the line is drawn, such that a line will be thinner at the beginning and wider at the end. This is less of a problem with hard lead (4H and up) but a lot depends on the abrasive qualities of what you are drawing on as well. The "weight" of line drawn with a sharply pointed pencil is determined by the "weight" of the lead, "HB" ("heavy black") is the middle of the range, equivalent to an ordinary #2 yellow wood pencil. A 4B pencil would produce a very black line, while a 4H would produce a very light line. Different weight lead can be sourced for the thin lead technical pencils, although you won't find that at your local 7-11, either.



    The purpose of the fine point is accuracy. We all are familiar with the need to loft full size ("Never measure from the drawing! Always from the written dimensions!" is the rule.) The width of a line on a drawing of a boat's lines can be equivalent to a half inch or more when blown up to full size, depending on the drawing's scale. The narrower the lines on the drawing, the closer the designer is going to get when taking up the offsets off the drawing (and few tables of offsets are completely accurate unless taken from a full sized corrected lofting.) The same goes for drafting instruments. The more expensive ones, now not made, are much more accurate. Here's a pair of"hairspring dividers" which are used by making a gross adjustment in the usual way by spreading the legs, and then may be very finely adjusted by turning the wheel on the leg which further moves the point to just the right spot you want. These will be found in all the major manufacturer's older top of the line cased sets.



    The thin lead mechanical pencils are fine for general use, although because the lead is often for general purpose use, rather than drafting, it will be too soft, or just plain inferior, and will smudge rather readily and make a big smudgy mess when erasing, especially if you are using an inferior eraser such as often are attached to the cheapo versions of such pencils. There is a wide range of them from "for kids doing math homework" to "professional level technical drawing." The same goes for lead. It often has to match the surface drawn upon. You use special lead for drawing on the modern plastic films, not lead intended for drawing on drafting vellum (paper.)

    When inking, you would go over the fine lines with whatever width pen line you wanted. Technical pens come in a variety of widths. The points on the old nibbed ruling pens have to be set for width of line by turning the adjustment wheel and are more versatile in that regard, but they do require some technique to use competently. (And, particularly with the cheaper ones that don't have hardened points, they will have to be sharpened every so often because drafting paper is quite abrasive. The old ruling pens are a lot easier to clean, though. The Rapidograph style technical pens have to be tediously disassembled to be cleaned and if they are not cleaned and the ink dries in them, they are generally totally ruined and must be tossed, which at $25 a piece retail, is not something you want to have happen.

    By the way, if anybody reading has a ruling pen and want's to play with it, note that they are not inked by simply dipping them into a bottle off India ink like an old fashioned writing pen. The ink has to be applied to the pen between the points without getting ink on the outside edges of the points of the pen. It is held there between the points by surface tension. It is applied with the small eye dropper that comes in a standard bottle of India or other drawing ink. (True India ink contains shellac and is thinned or cleaned with alcohol. Modern substitutes, often marked "for technical pens" do not contain shellac and pens using it are a lot easier to clean with just water and, if necessary, a bit of ammonia and water.) You want to keep ink off the outside of your pen points so it won't get all over your straightedges and curves and seep under them and ruin the drawing. Back in the day, draftsmen used a special inkwell made by Alteneder or Dietzgen which permitted properly inking a ruling pen with one hand. The ink was picked up out of the bottle on a spring in the cap which transferred ink to the pen when the pen was touched to it. The spring lifted out of the ink bottle when a lever was pressed with the heel of the hand holding the pen.



    Last edited by Bob Cleek; 01-26-2015 at 03:15 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Bob Cleek View Post
    The really beautiful "jewelry grade" instruments, hand made and fitted of German silver were no more, replaced by ordinary stamped metal. It really was a lot like firearms. In WWI, they carried finely made Springfields that could drive a tack at 50 yards and 50 years later in Viet Nam, they were carrying "throw-away" plastic and stamped metal M-16's that were lighter and sprayed automatic fire all over the place. The M-16 is certainly the better infantry weapon on today's battlefield, but an old M-16 can't hold a candle to an old Springfield in terms of fit and finish and pride of ownership.
    Yep. I got fed up with my modern (50 yo) tacky crap. So I bought these off Ebay.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    .
    Great descriptions, Bob. Thanks. Took me back to my early drafting days in the 60s.

    A couple of additional points from my own experience --

    • When using an ink pen with a straightedge, have the straightedge's bevel downwards to prevent any ink from flowing back in underneath. (And if your straightedge doesn't have a bevel, get one that does.)

    • A hard pencil (say 6H) not only draws a finer and lighter-coloured line, but if pressed on too hard can cut into the drawing surface. So if you need a darker line don't press harder, use a softer lead.

    • To store rapidographs long-term we disassembled them and kept the components in a tobacco tin filled with detergent. When wanted, rinse in water and reassemble. When in regular use during the day, a couple of shakes to move the internal cleaning wire up and down was sufficient to keep the pen operating.

    • Whatman paper was a much-prized drafting paper for pencil work. Drafting linen was better for ink (later replaced by plastic film).

    • To erase the ink from linen, first use a razor blade as a scraper, then an ink eraser, and then a bone, stone, or plastic burnisher to re-smooth the surface

    • A sheet of drafting linen, washed and rewashed until all the sizing was removed, made an excellent and long-lived rag for cleaning nibs on

    • Pencils were best sharpened with a single-edged razor blade to remove the wood and expose a long length of lead, which was then pointed on a sandpaper block

    • Both sandpaper block and linen rag were hung at the end of the rail at the front of the drawing-board for immediate availability

    • A drop-compass was a very handy piece of kit for drawing many circles of the same size quickly -- set the radius, hold the top with thumb and first finger, then spin the knurled wheel with the second finger

    • If you set your drawing stool at the right height, the drawing-board was a good surface to rest your head and forearms on for a quick nap


    Mike
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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Wooden Boat Fittings View Post
    .
    Great descriptions, Bob. Thanks. Took me back to my early drafting days in the 60s.

    A couple of additional points from my own experience --

    • When using an ink pen with a straightedge, have the straightedge's bevel downwards to prevent any ink from flowing back in underneath. (And if your straightedge doesn't have a bevel, get one that does.)

    • A hard pencil (say 6H) not only draws a finer and lighter-coloured line, but if pressed on too hard can cut into the drawing surface. So if you need a darker line don't press harder, use a softer lead.

    • To store rapidographs long-term we disassembled them and kept the components in a tobacco tin filled with detergent. When wanted, rinse in water and reassemble. When in regular use during the day, a couple of shakes to move the internal cleaning wire up and down was sufficient to keep the pen operating.

    • Whatman paper was a much-prized drafting paper for pencil work. Drafting linen was better for ink (later replaced by plastic film).

    • To erase the ink from linen, first use a razor blade as a scraper, then an ink eraser, and then a bone, stone, or plastic burnisher to re-smooth the surface

    • A sheet of drafting linen, washed and rewashed until all the sizing was removed, made an excellent and long-lived rag for cleaning nibs on

    • Pencils were best sharpened with a single-edged razor blade to remove the wood and expose a long length of lead, which was then pointed on a sandpaper block

    • Both sandpaper block and linen rag were hung at the end of the rail at the front of the drawing-board for immediate availability

    • A drop-compass was a very handy piece of kit for drawing many circles of the same size quickly -- set the radius, hold the top with thumb and first finger, then spin the knurled wheel with the second finger

    • If you set your drawing stool at the right height, the drawing-board was a good surface to rest your head and forearms on for a quick nap


    Mike
    1) Absolutely. Some good straightedges were made with rabbeted or beveled edges on both sides for inking. I've seen guys put masking tape, those little sticky-backed rubber dot "feet," or taped pennies to straight edges and curves to keep them off the surface when inking.

    2) Nifty trick with the Rapidograph pens. Rapidograph actually made a "humidifier" holder for pens that was air-tight and could be filled with water to keep them from drying out. So's people will know what we are talking about, here's an exploded diagram of the Rapidograph technical pen:



    The nib also uscrews for cleaning. The nib is a tube with an outside diameter equivalent to the width of the line it draws. There is a needle or fine piece of wire which runs down the center of the tube to regulate the ink flow.
    Here's a couple of good articles on the care and feeding of Rapidograph pens: http://www.scififantmodmadrealm.com/...phArticle.html https://crythebird.wordpress.com/201...pidographpens/

    Here's the humidifier they used to sell:



    The Staedtler and Eberhard Faber "Rapidograph style" technical pens are, IMHO, a bit better than the classic Koh-I-noor Rapidograph brand because the former two have a socket wrench built into the cap which attends to the disassembly for cleaning, rather than the little "wheel" that Rapidograph provides, which always gets lost and they have a silicon sheath inside the cap which seals the point and helps prevent drying out. The original Rapidograph pens don't have this and the points are exposed to the air, unsealed, inside the cap and so dry out rather quickly if you don't keep using them continually. (I'm talking about within a few hours with the fine points.)

    3) Time was, they made beautiful small scalpel like knives for erasing ink. They are pretty rare these days.

    5) They used to make regular crank pencil sharpeners for draftsmen that sharpened the wood, but didn't taper the lead so it could be sharpened on a sandpaper block. Dietzgen used to make a nice combination tack remover and lead pointer out of metal. They are also pretty hard to find these days. Of course, sandpaper blocks and pointing files were really messy because they generated a lot of graphite powder which would get on the drawing and smudge all over. Guys used to keep them in an envelope to keep the graphite from traveling. You'd have to be pretty careful or you'd have to wash your hands every time you pointed a pencil to make sure you didn't carry any of the dust to the drawing.



    Here's a drop bow pen you mentioned. (Very cool graphic you posted there!) This one has interchangeable ends for inking and for pencil. They were also called rivet pens, because in the days before welding, the draftsmen had to draw the rivets in where they were supposed to be placed. Modernly, a lot of guys used circle templates, but they were tough to ink neatly and make a mess sliding around on the drawing if you're not real careful.



    Last edited by Bob Cleek; 01-26-2015 at 11:36 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Bob, in the drop bow pen in the picture, I don't see how the pen holds ink. Does something go between the points?

    My Dad had a grey plastic lead pointer, but it was rectangular. He had one of the ubiquitous red and silver lead holders. I thought the whole process was the coolest thing ever.

    I'd have more confidence in your pen guy if he weren't A) a Michael Jackson fan, and B) a guy who builds models of space fighting weapons that don't exist.
    Last edited by Jammersix; 01-26-2015 at 11:59 PM.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Hey, Wooden Boat Fittings, did you ever use one of these? I have a very old copper based one (original "pat. applied. for" make) with a celluloid arm. I found it a cute toy, but practically useless. A length of tape on the edge of my triangle works a lot better for me. It's now in my collection of "WTF is this?" tools. Nobody who's seen it has ever guessed what it is for. In the context of this thread, it's no secret it's a drafting instrument, though.


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    Default

    Quote Originally Posted by Jammersix View Post
    Bob, in the drop bow pen in the picture, I don't see how the pen holds ink. Does something go between the points?

    Just India Inknk. The miracle of surface tension.
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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Jammersix View Post
    Bob, in the drop bow pen in the picture, I don't see how the pen holds ink. Does something go between the points?
    The nib is relaxed in that photo. The points would be wound in untill nearly touching before being filled with ink. Then as Nicholas says surface tension holds the charge.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Bob Cleek View Post
    Hey, Wooden Boat Fittings, did you ever use one of these?
    I'm sorry Bob, but that's a new planet in my ken. Any idea what it is? (In my defence, I should say I was only a draughtsman for a couple of years before qualifying as an engineer, when I left such childish pursuits as draughting behind me.... )

    Mike
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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Wooden Boat Fittings View Post
    I'm sorry Bob, but that's a new planet in my ken. Any idea what it is? (In my defence, I should say I was only a draughtsman for a couple of years before qualifying as an engineer, when I left such childish pursuits as draughting behind me.... )

    Mike
    It's a "section liner." An ingenious device for drawing section lines in engineering drawings. It's placed on the T-square with the arm set at whatever angle you want. By pushing the lever on the mechanism on the left side of the instrument, the bar, and hence the straightedge set at an angle, is advanced whatever distance you set, thereby permitting the drawing of a succession of closely spaced and perfectly spaced parallel lines to indicate a surface that has been "cut away" in the drawing. Pretty rare to come across one these days. This one is now on ebay for $41 bucks. It's in pristine condition. I'm interested to see what it ultimately goes for.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Quote Originally Posted by Wooden Boat Fittings View Post
    I'm sorry Bob, but that's a new planet in my ken. Any idea what it is? (In my defence, I should say I was only a draughtsman for a couple of years before qualifying as an engineer, when I left such childish pursuits as draughting behind me.... )

    Mike
    It's a "section liner." An ingenious device for drawing section lines in engineering drawings. It's placed on the T-square with the arm set at whatever angle you want. By pushing the lever on the mechanism on the left side of the instrument, the bar, and hence the straightedge set at an angle, is advanced whatever distance you set, thereby permitting the drawing of a succession of closely spaced and perfectly spaced parallel lines to indicate a surface that has been "cut away" in the drawing. Pretty rare to come across one these days. This one is now on ebay for $41 bucks. It's in pristine condition. I'm interested to see what it ultimately goes for.

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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    After a two-year long research and prototyping project, there is now a Kickstarter project where you can purchase nautical drafting curves:


    - Ship Curves One: a single-piece that contains more than a dozen ship curves.


    - Dixon Kemp Curves: a five-piece set of pear-shaped ship curves attributed to a mid-1800s maritime architect.


    - Copenhagen Ship Curves: both the standard 56-piece set as well as an extended 120-piece set.


    You can find out more about the project and research from my blog on the Copenhagen Curves website or purchase directly through my Kickstarter project.

    http://copenhagenshipcurves.com/
    https://www.kickstarter.com/projects...en-ship-curves


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    Default Re: Set of Copenhagen curves (ship's curves) on eBay now

    Well, the cardinal sin in this forum is offering anything for sale or personal gain. (WoodenBoat has a great advertising section and because we all support WB, we comply so they can make the money they need to remain solvent.) I'd urge you to post an ad in the WB Classifieds because you have a product that is nearly unobtainable, yet still very much sought after by WB readers.

    That said, I hope the "powers that be" will turn a blind eye to this "infraction," as we've all been looking for these tools for a long while and have had to compete with the collectors on eBay to scrounge what we can, often at exorbitant prices. (And judging from the collection you've illustrated on your blog, yes, that means you! ) The Dixon Kemp style set was apparently completely unobtainable, until now, thanks to you.

    I note that your blog, which is a great overview, seemingly overlooks discussion of the use of curves. Some readers might misapprehend that the usefulness of curves is limited to the shape of a particular curve, which is not the case. Curves are used, as needed, in combination with one another. Thus, the "standardized shapes," which are designed to overlap and draw a fair line continuing from one to the other. Their shapes are very important because they complement one another and when used properly will always yield a fair curve.

    This is readily apparent when using multiple curves properly. Counter-intuitive as it may be, curves aren't intended to limit the designer's creative options to the curves themselves nor are the curves to be drawn limited in size by the curves one has at hand. A sheer, for instance, does not have to be exactly the same as a particular curve describes. Rather, all drafting curves should be used by first laying down a series of points describing the desired curve, and then testing curves available to touch a series of points along the total curve. Then, that much of the curve is used to draw the curve over those points. Then, another curve is selected which fairly overlaps the line drawn for a fair distance and also covers the next points in the curve line, and the line is drawn for as far as can be covering the points, and so on until the full desired curve is drawn. (The curves will also often reveal slight unfairness in the line of points, in which case, the curve dictates fairness, not the points.) If the draftsman's curves are fair and properly shaped, then the resulting curve line drawn from a number of curves will be fair. The differences in the curves you have noted, particularly with respect to the much older wooden curves, likely results from manufacturing errors or the common practice of draftsmen of old to sand the edges of their wooden curves when they might become nicked from use. The modern numbered plastic curves should all be exact matches from manufacturer to manufacture. Reshaping a curve to accommodate a CAD program will likely spoil the whole point of a set of drafting curves. If I were you, I'd replicate the plastic curves you have exactly, rather than taking a collection of old wooden curves and modern plastic curves and averaging their shapes! The wooden curves are not necessarily reliable in the same way the later plastic ones are, the later ones having had the advantage of much more accurate manufacturing technology.

    Use of drafting curves, illustrated using a French curve:



    Copying drawings in enlarged or reduced size or scaling a smaller vessel up or down in size from the originals does not involve the need for a differently sized set of curves. Rather, as illustrated above, the points that describe the curves are transferred from one drawing to the other using a proportional divider and the resulting curve described by the points is drawn anew with whatever curve in the set suits the curve described by those points. If a drawing is to be copied from a book at three times the size in the book, the distances of a given point from the baseline and nearest station line on the enlarged drawing will be exactly three times the same distances on the copy. For the greatest accuracy, the preferred instrument for this task is a ten inch decimally- scaled proportional divider with Vernier adjustment which will yield proportions down to .005". (Marked with decimal equivalents, not "lines and circles." Sometimes called "universal" scaling because any proportion whatsoever is marked on the instrument, rather than just a few at "1/2, 1/3, 1/4" and so on, requiring guesswork for anything in between.) The most commonly available of these is the Keuffel and Esser "Paragon" model. With this instrument, any lines drawing of any size can be very exactly copied to any size and scale desired.



    There are two types of radius curves, the "railroad curve," and the "highway curve." The difference is that one type is marked with the length of 1/8 of the circle described as the length of the arc and the other marked as the length of the chord. I can never remember which is which, but, IIRC, the "railroad curve" is marked with the length of the arc because in that fashion they indicate the length of rail needed to build a railroad to that curve. This is of no moment unless you are building a railroad, I guess, but it's an interesting bit of trivia. Radius curves are handy in naval drafting for quickly drawing the proper crown of deck beams and such, but, as Chapelle would say, otherwise pretty useless for naval architecture.

    I would differ with Mr. Chappelle's assessment of the uselessness of French curves in naval drafting. While he is generally correct, he paints with too broad a brush. French curves are, more accurately put, "less useful," and "useful as a supplement" to a full set of ship's curves, and more so when drawing smaller detail. Ship's curves, however, are sized to best accommodate the customary size drawings in the trade. (In traditional naval architecture, the 72' drawing board was generally used to accommodate long drawings at useable scales. Hulls aren't shaped well to fit on 18"x24" sheets of paper!)

    As described in Kemp's book, his set of curves comes in two sizes, large and small. One size limits the set's usefulness by half.

    In summary, I'd say that a set of curves is a tool that is much more flexible and useful than just the curves available alone and that the "modern" plastic ("Luxite" was Keuffel and Esser's trade name for them) curves are far more durable and useful than the old fashioned wooden ones.
    Last edited by Bob Cleek; 08-03-2017 at 04:34 PM.

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