[tvlawyer]

How does one measure and mark a radius when the plans say "cut a 3/2 radius", "remove material to make 1/4 radius" ?

I failed geometry in high school.

 

[az_gila]

Template

larry,

Use a template.... similar to these

http://www.timelytemplates.com/f_circles/Tcircles_16.htm

....can be obtained at a drafting store (do they have these any more?) or a good art store.

UPDATE... Office Max has them....

http://www.officemax.com search for "template"

Radius is half of the hole size (diameter).... example - a 1/4 inch radius is the curve made by a 1/2 inch hole in the template.

The template and a Sharpie pen can easily mark the curve you need. A small radius can usually be done by eye...

gil in Tucson ... didn't like geometry, but passed it....

 

[G-force]

The small ones you can usualy eyeball. The point is they dont want a sharp, 90 degree corner. An easy way to check is to use drill bits. If the call out is lets say a 1/4" radius, grab a 1/2" diameter drill and hold it up to your corner. If you want to actualy draw it out on something, use a 1/2" washer and trace the inside. Remember, radius is from the center of the circle to the edge so for a 1/4" rad use a 1/2 drill, 3/32" rad use a 3/16" drill, etc. Or just go buy a set of radius or fillet gauges from a tool supplier.