Measuring radius of spherical cap

Don Y · 2016-08-14T21:56:09+00:00

I can only access part of it. But, have a fairly large surface area to work with (about a 3" diameter slice). How can I get a *reasonably* good estimate of its actual radius? I thought, perhaps, a "precisely" cut circular opening that could sit on the surface and then use that (knowing its thickness) to measure to the "peak" of the surface protruding within (?) E.g., a dial indicator riding on that material in which the opening is cut... The rest being math.

Aug 14, 2016 47 Replies

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Michael A. Terrell 9 years ago

Subject: Spelling Lesson The last four letters in American.........I Can The last four letters in Republican.......I Can The last four letters in Democrats.........Rats End of lesson. Test to follow in November, 2016 Remember, November is to be set aside as rodent extermination month.

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Albert van der Horst 9 years ago

A poor man's instrument may be a well-chamfered nut and bolt. Sit the nut flush on a flat surface, turn the bolt till it touches. Measure the length of the bolt plus nut. Retract the bolt. Sit the chamfer on the sphere, turn the bolt till it touches. Measure again, giving a difference d. With radius r of the chamfer, we get ( r^2+d^2 )/2d for the radius of the sphere.

Groetjes Albert

Albert van der Horst, UTRECHT,THE NETHERLANDS Economic growth -- being exponential -- ultimately falters. albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

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