![]() ![]() It is a precursor to the spirit level and used to establish a vertical datum. Plumb Bob Golf 101 History of Plumb Bobbingīefore diving into this method, which is sometimes controversial in the golf world, let’s go back in time to see where it all started.Īccording to Wikipedia, “A plumb bob, or plummet, is a weight, usually with a pointed tip on the bottom, suspended from a string and used as a vertical reference line, or plumb-line. It just might make reading greens at your local course that much easier. Keep reading to learn more about this unique way to read greens and how you can start trying it out today. Recently, plumb bobbing has lost some of its popularity thanks to advanced heat map green reading books and other systems like AimPoint. Some golfers swear by it, while other golfers don’t believe in the plumb bob technique. The next time you’re playing golf and see someone do this, it’s called plumb bobbing.Īs you will soon learn, plumb bobbing has been around for a long time and helped many golfers. When someone hotels their putter up, they’re actually using a system to help them read greens. It’s a good question because in a game where everyone wants a leg up on competition, it might help the average golfer. Reverse the instrument and check.If you’re like most players, you have probably wondered “What are golfers doing when they hold the putter up?” If using a plumb bob, center the instrument with the plumb bob, then bring the crosshairs to the ground point.If not using a plumb bob, then bring the crosshairs back half the amount of their reversed instrument position.To correct the OPA with the adjusting screws: There may be one to four screws, Figure G-20, and they may be exposed or under a cover. The adjusting screws for the optical plummet crosshairs are located forward of the eyepiece. ![]() A plumb bob will hang vertically regardless optical plummet condition. Use a plumb bob to center the instrument over the ground point. Rotating the instrument to various positions and checking the plummet shows it follows a circular path centered on the ground point, Figure G-19. While sighting through the plummet, slide the instrument across the tripod head halfway back to the ground point. By SetupĬarefully loosen the instrument attaching screw. The instrument is vertically over a point halfway between the ground point and the current plummet sight location, Figure G-18. So how much error is there? When the instrument was reversed, the amount the mark moved off the point is twice the error, Figure G-17. Because the OPA is bent 90° thru a prism, the vertical segment of the OPA is not vertical, Figure G-16. A maladjusted plummet means the crosshairs are either too high or too low so the horizontal segment of the OPA is not horizontal. The only part of the OPA which can be adjusted is the crosshair reticule in front of the observer's eye. If the plummet it is pulled off the ground point, Figure G-15(c), then it is maladjusted. If it is still on the ground point, Figure G-15(b), it is correctly adjusted. ![]() Rotate the instrument 180° and check the ground point through the plummet, Figure G-15(a). Precisely level the instrument and use the optical plummet to accurately set up over a ground point, Figure G-14. ![]() The other type is discussed in Chapter B. This chapter covers rotating plummets because those are common on theodolites and TSIs. There are two ways to check and compensate for a maladjusted optical plummet depending whether it rotates with the instrument or not. The vertical component should coincident with the instrument's VA. When the instrument is level, the OPA is both horizontal and vertical. The optical plummet takes the place of a plumb bob for instrument set up over a ground point. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |