Sagitta Rule: Difference between revisions
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It is easy to construct a [[Sagitta Rule]]. Obtain a large paint stir stick (for 5 gallon buckets of paint) from a big box store or where paint is sold. Print the following paper rule. Cut out and tape or glue to the end of the paint stir stick. | It is easy to construct a [[Sagitta Rule]]. Obtain a large paint stir stick (for 5 gallon buckets of paint) from a big box store or where paint is sold. Print the following paper rule. Cut out and tape or glue to the end of the paint stir stick. | ||
* [http://ibls.org/files/2020/CharlesField_TrackPanelJig/150_Sagitta_Rule_for_10_Foot_Rail.pdf | * [http://ibls.org/files/2020/CharlesField_TrackPanelJig/150_Sagitta_Rule_for_10_Foot_Rail.pdf Sagitta Rule for 10 Foot Rail (PDF)] | ||
[[File:2020-12-01 16.28.00.jpg|thumb|center|500px|A sagitta rule for directly measuring the radius of 10 foot sections of rail.]] | |||
== Use == | == Use == | ||
Revision as of 22:34, 1 December 2020
- In geometry, the sagitta of a circular arc is the distance from the center of the arc to the center of its base. It is used extensively in architecture when calculating the arc necessary to span a certain height and distance.
In Live Steam a Sagitta Rule is used to directly measure the radius of a curved section of track.
Construction
It is easy to construct a Sagitta Rule. Obtain a large paint stir stick (for 5 gallon buckets of paint) from a big box store or where paint is sold. Print the following paper rule. Cut out and tape or glue to the end of the paint stir stick.
