Ancient Tools - The Stringline

[Stanley Covington]

Ah, the magic of wrap angle.

The mechanical advantage of a capstan (ratio of load to required holding force) is exponential in the wrap angle. That's why winches work so well. 10 turns is probably massive overkill though.

I think you misunderstand, Patrick. The loop in the stringline is wound before it is hooked over the nail. No mechanical advantage, just a simple friction knot that is very quick to make, adjust, and undo.

[Patrick Chase]

I think you misunderstand, Patrick. The loop in the stringline is wound before it is hooked over the nail. No mechanical advantage, just a simple friction knot that is very quick to make, adjust, and undo.

Perhaps so, but it seems to me that the line is acting as its own capstan in this instance, with the same underlying physical principal holding things in place.

[Stewie Simpson]

http://www.finehomebuilding.com/2014...ies-with-a-tug

[Stanley Covington]

Perhaps so, but it seems to me that the line is acting as its own capstan in this instance, with the same underlying physical principal holding things in place.

Give a try, Patrick, and you will see how it works. When you twist the loop, the end of the line is pointed back towards the first pin or nail. After twisting and then hooking the line over the nail, pull the line's end hard towards and behind the nail, and let it go slack. You will notice how the twisted line bunches up and locks the knot in place. No extra tension is created in the line.

To release the knot, simply pull the line back from behind the nail, and tug it in the direction of the first pin or nail.

Its a pretty slick knot, and I have no doubt, very ancient.

[Stewie Simpson]

Some good info on how to straighten timber stud wall. https://www.youtube.com/watch?v=esP1nhviKok

[James Waldron]

[snip]

Please share some of the old-timey boat-building techniques with us.

Stan

A very good source of boat building techniques and tips (mostly traditional) is better than I could do:

https://www.youtube.com/user/TipsfromaShipWright

Comes with an impressive "Yankee" accent and intonation. Very watchable. Covers more than woodworking.

Have a bit of fun; he's currently in the early stage of designing and building a "Peapod" design that looks like fun.

Edit: Lou is pretty dismissive of safety requirements, and has enough experience to "get away with it" - so far. You may wish to take a bit of care with some of his technique. Every once in a while, he'll do something that I find horrifying.

[Stanley Covington]

A very good source of boat building techniques and tips (mostly traditional) is better than I could do: https://www.youtube.com/user/TipsfromaShipWrightComes with an impressive "Yankee" accent and intonation. Very watchable. Covers more than woodworking. Have a bit of fun; he's currently in the early stage of designing and building a "Peapod" design that looks like fun.Edit: Lou is pretty dismissive of safety requirements, and has enough experience to "get away with it" - so far. You may wish to take a bit of care with some of his technique. Every once in a while, he'll do something that I find horrifying.

James:Wonderful stuff! Thanks a lot. Quite a character with his suicide shifter and scary bandsaw technique. Fun and worth watching. What do you think of the quality and likely performance of the end product?Stan

[Mark Stutz]

Thanks Stan. I dusted off my dividers after reading your previous thread. The late time I even thought of this technique was when I was working as a construction laborer many years ago. I saw the carpenters using the technique that Steven described to put up concrete wall forms. Hadn't even considered it applicable to anything but construction.

Now I just have to remember to apply these new tools when I am working.

[James Pallas]

When you are trying to fair a curve by hand you can get some positive info by running a string on the curve and being able to quickly assess the highs and lows. Important here is that it doesn't mater how large the area is, for the most part. 3" or 3'.
Jim

[James Pallas]

These are just things I have done in the past. A quick way to make a half pattern for an ellipse. Mark an x y axis on you pattern decide how wide you want your half pattern. Mark half of that on your pattern. Decide how long you want your pattern, mark that on the other axis. Put the piece verticle in your vise. Hold your string at the two longer marks. Let it hang down to touch the width mark. Now carefully mark along the string and you have it.
Jim

[James Waldron]

James:Wonderful stuff! Thanks a lot. Quite a character with his suicide shifter and scary bandsaw technique. Fun and worth watching. What do you think of the quality and likely performance of the end product?Stan

Stan:

Lou's quality is quite good in everything I've seen. His designs are rather dated, but will perform, I expect, at least to the traditional levels. These are not "high performance" boats or racing boats for the most part, so performance is relative to a mission. For the uses they are intended to serve, they are pretty nice looking designs.

He also takes on a lot of very challenging restoration projects on antique boats. A lot of creative woodworking goes on in those projects.

[James Waldron]

When you are trying to fair a curve by hand you can get some positive info by running a string on the curve and being able to quickly assess the highs and lows. Important here is that it doesn't mater how large the area is, for the most part. 3" or 3'.
Jim

One can do a far better job of fairing a curve with a batten. I have about a dozen in different stiffnesses and differing lengths for the purpose. Yes, storage is a hassle, but when you really need a fair curve (whether in two or three dimensions), it's good to have them. Most of mine are made of 3 to 4 plies of laminated Western Red Cedar, with each ply at about 1/8" - 1/4" and using epoxy laminating adhesive. They range from 8 feet to 20 feet in my shop. (If I had a need for shorter battens, I'd probably use fewer, thinner plies.)

[steven c newman]

One other item I learned the hard way....those little "Line Levels"? Do NOT use them..as soon as you install one on a stringline, it will sag right there.

[James Waldron]

These are just things I have done in the past. A quick way to make a half pattern for an ellipse. Mark an x y axis on you pattern decide how wide you want your half pattern. Mark half of that on your pattern. Decide how long you want your pattern, mark that on the other axis. Put the piece verticle in your vise. Hold your string at the two longer marks. Let it hang down to touch the width mark. Now carefully mark along the string and you have it.
Jim

I think you'll find that the curve defined by the hanging string is a "catenary" and not an ellipse segment. It is actually closer to (and indirectly related to) a parabola. You might find good information on the catenary curve on Wikipedia or, if more rigor is wanted, at Mathematica.

If you really want an ellipse, Tolpin and Walker have a good construction technique with divider and straight edge in one of their books. I'm not sure which one, but Google should tell you more. I've used it for some time from memory; I learned it from my father.

There's also a string technique, but it's complicated by requiring one to find the two foci of the ellipse. That can be an elusive requirement if specific dimensions are wanted. Once the foci are determined, pins are placed at each of the foci and a string is looped around both with enough slack to reach to the intended width on one side or the intended length at one end. Then a pencil is inserted inside the loop and tensioned against the pins and translated around creating the ellipse.

[Stanley Covington]

Stan:

Lou's quality is quite good in everything I've seen. His designs are rather dated, but will perform, I expect, at least to the traditional levels. These are not "high performance" boats or racing boats for the most part, so performance is relative to a mission. For the uses they are intended to serve, they are pretty nice looking designs.

He also takes on a lot of very challenging restoration projects on antique boats. A lot of creative woodworking goes on in those projects.

Do you know Lou well?

Boat design and building has always fascinated me. My wife grew up with a 24ft glass "yacht", and loves ships, and I grew up with ski boats and diving, so for a long time we wanted to build our own sailboat and travel the world. When I looked more closely at the cost and long-term burden of owning a wooden clothesline, not to mention the instability of such a lifestyle, we changed our minds, but the romance of sailing ships has not left my heart.

I have deep respect for men that can build those beautiful and functional sculptures. Lou's may not go that far, but they look like a lot of fun. He gets his hands on some beautiful wood.