Measuring radii

use a machinist square on the corner and measure from the 90' of the square to the longest measurement to the block.
Hope i said that right. If not I'm sure some one will correct me.
 
use a machinist square on the corner and measure from the 90' of the square to the longest measurement to the block.
Hope i said that right. If not I'm sure some one will correct me.
My machinist squares are all notched in the inside corner, so that wouldn’t work. I like the idea, though. A carpenter's square might work. Using a caliper’s inside blades, bury one blade in the corner of the square and measure the radius.

Tom
 
I use CAD. measure and draw the the intersecting lines to the curve. Draw an intersecting line on any point of the curve somewhere near the middle of the curve. Create a circle that intersects the 3 points of the curve. Then dimension the circle radius.
 
If you need a .400 radius you turn a washer to .800. Or bore it to .800 and use a segment
of that to check an od radius.

radius is a rounded FORM to an edge or corner.
Seems like everyone thinks a radius is formed with a true arc starting at the center of a circle. But if I hand grind a radius on the cutting edge of a turning tool. The way I check it is with a radius gage . And I don’t think math will be able to check it.
 
Last edited:
Maybe a couple of straightedges held on the 2 surfaces adjacent to your radius, then measure from the corner formed by the intersection of the straightedges to a couple of points on your radius? I say a couple of points because it's going to be a handful to hold all that together! It'll work, it's just a matter of dexterity.
 
Back
Top