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less than your eye could ever hope to notice. Even if you looked
i really
hard.
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less than your eye could ever hope to notice. Even if you looked
i really
hard.
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Look in your calculus textbook, right there in Chapt 7.
*I think I can do this but I'll need the flexural modulus of the string, the weight per linear unit, and the tension.
*nothing that i can measure..if i set up a string and block.. and set a lazer level on the same plane ..i can't discern a sag in the line..so.. for framing and installation purposes, there is no drop in the line..b but hey, whadda i no ?
*Mike, Would you trust a line level?
*no. too much line sag.. and the vial isn't accurate enough ..sure have been a lot of foundations built with them though, just not in my tool box....
*Mike, Thanks, you just renew my faith in you opinions.
*No, it not a riddle but something the super said last week. I want to build a block garage/shop i was going to lay to a line with the addition of a four foot level. But super said I needed a lazer level to keep on line. I alway thought that a spring line pulled tight was pretty close. He said spring lines are only good for vertical layout
*b TVMDCThat's why they call him super. Use a Laser level.
*Bill, In Johnnie defense, a good mason would use a laser to get the footers level, but would set his block to a line to keep his wall straight and use a 4' level to keep his block running true between his leads or corners. The leads may be checked with a laser but I doubt they would set every block with one.
*Johnnie,
View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle
*Well gosh... I wonder how anything ever got build correctly in the several thousand years previous to the invention of the laser level?? Seriously though, your super is partially correct. A laser, builders level or transit should be used to check the footers and masonry corners. After that, lay your block/brick to a string line. (What Jake said)Here's a quiz question for ya: If a taught string line is, say 50 miles long, does it follow the curvature of the earth? If not, and the 2 end points are 10' high, how long must the string be before it touches in the center (assuming a smooth topography)?
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This is a test.
This is only a test.
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Johnnie,
50' is a long way to trust a string. Your superintendent is right on. Use a lazer or a builders auto level, but don't trust a string over that distance. It will take one heck of a pull to keep it straight. I've snapped a few trying to get a string straight over less distance. Set your footers with the lazer or auto level and then use a string and your eyeball after you've set the first few courses.
Ed. Williams
*Let's see now...how did that laser work when the Empire State Building was built? Oh, yes how about the fine mansions on Sea Island? More mundanely, the first house my Dad did?Come on guys; just because you can do something to the thousandth of an inch doesn't mean you need to: Or that it makes any practical difference.
*Matt,If your hypothetical string has no sag, it kisses the ground in the center when it is 7.78 miles long.Bill
*The error in the laying of each block has got to be bigger than the error in the string at the middle of 50'.
*those were all laid out and kept on line by transits, levels and theodolites... remember?back in ancient history... like four years ago.. evry good builder had a level.. and some had transits...some used water levels..string lines are for line.. they aren't for level.. and a hanging string line is a plumb-bob...a good three-directional laser level can give you Square / Plmb / & Level..but it can't give you straight.. string lines give you straight...b but hey, whadda i no ?hi, joe... packin your bags for Caperfest next summer ?
*From much string pulling and siding work, 50' is sag length unless the tension is way way up...I find carps not realizing how much tension often...that's why there are different colors of chalk...And if snapping that far, we always hold the middle if possible and snap the halves...crank the tension up!...near the stream,aj
*.... trap it... and snap it....
*Why not just check the string line against a water level at the middle and then you'll know exactly how much it sags?
*That is a good idea but is a water level a perfectflat level?
*yes, a water level is a perfect level for all practical purposes..not as handy as teh new lasers.. but it's been around for a couple thou years.. speculation is the egyptians used water to check the level of their foundations..the way you would use a water level .... or a transit, or a laser.. is to set a reference line all the way around the building.. use this to check your courses.. and your soffits , window casing headers , door trim..so you can get good accurate siding layout and plan ahead....
*Johnnie:Mike's post is right on as usual-the guy should consider writing a book! I think there is a discussion in the archives about making a reservoir type water level or just do a web search.You can try Spiderwire brand fishing line but it is rather hard to see. Very strong and lightweight though.
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That's only if both ends of the line is eaxactly 3.61625 ft. above sea level on Neptune.
*Or the Tower of Piza
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We were taught to use dentil floss in carpenter school. That was the line of choice before the popularity of lasers for large suspended ceiling systems. I think I tried it once and it worked well.
blue
*Dentil floss--we usually just brush them and call it good.Corbels get an anti-plaque rinse, however.
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Zircon makes a water level that works over 50'. They are pretty cheap and easy to use. Check your favorite toy store. Or Tool Crib.
*the dental floss idea is wonderful for those days when the wife packs leftover ribs in the lunch box. other than that im skeptikal. i have used jet line for years and it never fails for building long walls or soffits.
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What's jet line?
*I used a water level from the ground up. It is the most accurate, water can't lie. It's a little slow and it definitely helps to have a friend (make sure you are both reading from the top or the bottom of the meniscus. One of the great things is that you don't need a line of sight. I made mine from 100 feet of 1/2 clear plastic tube, water and a little food coloring for visibility. I found a couple of plastic caps to keep the water in when not using. The whole deal was 15 bucks. I verified the accuracy of my batter boards with a rented builders transit. I was not able to duplicate points as accurately with the transit as the water level.So, here's a funny story, I hired this brick mason, nay, brick bat to brick up a skirt around my foundation. I arrived to find one end of the back wall 1-1/2 lower than the other end. Visible from sea level on Neptune. The brick bat told me "your house was out of level". When I asked how he determined this he told me he started on the front corner of the house with a 4 foot level transferring marks 4 feet at a time till he got all the way around! Oh, brother. After he fixed his unlevel wall, I threw him out and finished myself.
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How much fall does a tighten string line, in fifty feet
*I don't know Johnnie,How much?Ed. Williams
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Water may not lie but it can make you talk to yourself plenty. Kinks, bubbles, dirt, bubbles, mildew, bubbles. It was taking longer to get the damn thing ready to use than to actually use. Works good in shorter lengths and with good tubing but I just couldn`t handle dragging around 100' of it any more. I bought a Sprectra Physics with auto level and you'll need a gun to get it away from me. I'm just looking for reasons to use it all the time... 'course, at that price you should be using it all the time (and I`m not). But hey, I cut may swearing by at least 90% and am home for dinner on time. By the way, braided deep sea line, about 90 lb test, and root on it till your fingers bleed. Works good in the chalk box too if you can`t go the 45$ for the ink line.