Same as for internal corners, several ways:

1. For general radii, on the ends of connecting rods for instance, a rotary table is a pain as it is only too easy to rotate a tad too far and leave an indent. I prefer to use filing buttons. Although controversial I regard filing buttons as sacrificial and leave them soft. It is often quicker to use buttons than mess about setting up the job on a rotary table

2. A rotary table for complex radial slots that need to be accurate in size and placement

3. CNC mill, especially good for parts with multiple radii and splines

4. Mark out and file by hand

5. Machine on a lathe if the geometry of the part allows, that can include turning a circle and then cutting away waste material

Andrew

Radii can be achieved with a boring head and also by calculating many intersection points. The maths are square root of radius squared minus distance moved squared. easy with a CAD package but not essential.

A CNC mill can machine a curve but it can also be done by calculating the x,y coordinates for the radius manually.(although very slow and time consuming). Some DRO displays have a function that calculates and displays the values for you. The smoothness of the circular cut will depend number of moves.

A variation on this I've used successfully is to draw a scaled-up version of the shape (not necessarily a simple curve) on graph-paper, then read off the X-Y co-ordinates direct from the graph-paper, allowing for the diameter of the cutting tool. Finish with a file.

Edited By Bob Unitt 1 on 18/07/2023 11:58:23

Edited By Bob Unitt 1 on 18/07/2023 11:59:29

Filing buttons 95%of the time and soft as Andrew.