Shows how to use a transit to locate a building correctly on the lot, plan proper grades with minimum excavation, find Building Layout Author, W.P. Jackson. Building Layout,WP Jackson. Shows how to use a transit, to locate a building correctly on the lot, plan grades with minimum excavation, find utility lines. : Building Layout () by W. P. Jackson and a great selection of similar New, Used and Collectible Books available now at great.
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These are extremely precise instruments.
A vial with a sensitivity of 45 seconds ” per 2 mm is more sensitive than one with a 90 seconds ” per 2 mm sensitivity. In most units, the markings on the level tubes are 2 mm apart. More and more trades are using them to save time, cut costs, and insure accuracy in their work. Instead of a vernier scale, a theodolite is equipped with an optical micrometer scale.
Write Your Own Review You’re reviewing: Position the tripod legs so the center of the tripod head is approximately over the centering point and the tripod head appears level. Telescopes come in one of two types: If the radius is large, a small vertical movement on one end of the tube causes a large displacement of the bubble. Since you use a transit for its accuracy, there is no substitute for an accurate instrument w.p.jackon of the size of the job. This practical handbook explains these valuable skills and shows builders and tradesmen how to use the builder’s level, plot plans, lot descriptions and surveying principles to be sure the building is laout the right location and is built square, level and plumb.
Figure shows the principle of the optical plummet. Using a transit with an optical plummet provides a faster and more accurate method of centering than the plumb bob. You must then reposition the tripod. Crosshairs in the telescope permit the object sighted to be centered in the field of view.
Figure shows two theodolites, each with a micrometer scale. This means that for each 2 mm the bubble moves in the tube, it forms an angle equal to the sensitivity of the arc given. Explains how to plan sewer connections, level a foundation that’s out of level, use a story pole and batterboards, work w.p.jackaon steep sites, buulding minimize excavation costs. A tube with a sensitivity reading of 8 minutes seconds would form an angle of 08′ 00″ at a radius of 2 feet 10 inches 2′” with each 2 mm movement of the bubble.
Building Layout – Surveying Guides – Books and Software – Craftsman Book Company
The transit is designed to produce precision work. It replaces the plumb bob used s.p.jackson most transits. A 26x instrument may be used for work up to feet.
Thus the radius of the tube is a measure of its sensitivity. The instrument is set up over A, centered over the tack and properly leveled. The instrument is set up over A to locate D. The optical plummet serves the same purpose as a plumb bob, but w.p.jacksonn more accurate because it is not affected by the wind. There is no substitute for accurate layout layouy foundations, walls and floors. When the instrument is properly set up it is directly over the bhilding. It will be centered on different points such kayout a when the telescope is revolved.
If you are setting up on a paved surface, be sure the points are secure. Be sure the transit you select has the power, the precision, and the versatility you need to meet all your requirements for the present and the future. Yet few builders know how to use a transit to locate the building on the lot correctly, plan proper grades with minimum excavation, find utility lines and easements, establish correct elevations, lay out an accurate foundation, set correct floor elevations and plan stairways.
If the tripod head is too far out of level, the transit can not be leveled with the leveling screws. Points A, B, and C have been located. See Detail 1, Figure The right transit for you depends on your job requirements. Level Tube Sensitivity The more sensitive the level tube, the greater the precision that may be obtained. Instead it will be centered over another point, a, resulting in an erroneous reading. About the Author W. Figure shows a transit with a 20 second vernier reading.
A level vial with a sensitivity of 90 seconds ” per 2 mm is more sensitive than one whose sensitivity is 14 minutes ‘ per 2 mm. Builders need them to lay out foundations, plot lot lines, establish grades and excavations, and for many other uses. Jackson There is no llayout for accurate layout of foundations, walls and floors. Masons need them to level walls and foundations.
A theodolite is essentially a more precise transit. Hundreds of valuable suggestions are included: Theodolites are used where precision work is essential.