Michael,

There are two ways of doing this but the basics are that you spin a tool at a speed relative to the round bar i.e. chuck 600 rpm, tool 100 rpm so that the tool hits the metal six times, the old method is by using gearing, the newer method is by synchronising the chuck and tool with motors and encoders. You could use a pecking unit but this is still timed via gears to the chuck.

I've never built one but I've installed machines in companies that do the above.

Martin P

Edited By martin perman on 29/11/2015 09:48:44

This has been covered in one of the magazines in the past, but I can't find it in the indexes under hexagon or polygon.

There is another method that uses a cam and follower, but IIRC the cam is not simply a hexagon

Neil

Here's a couple of uTube clips;

**LINK**

**LINK**

My vague memory from the past recalls something along the lines of the first one, but with a single point tool travelling 6 times faster than the workpiece.

Ever since I bought the Super 7 I've wondered about the feasibility of coming up with something, particularly on the Myford with a 60 tooth bull wheel, which would divide quite easily.

Edited By peak4 on 29/11/2015 11:08:28

For one of our cnc..we had a macro to TURN polygons…ie with norma turning tools..it combine movement in X ( and z of course) with the spindle movement axis C…seeing this turning at 300-400 rpm was mesmerising. ..
Flats were pretty flat ( effected by tool setting…tnrc)
Machine was a Warner Swasey…lovely machine..tail stock rotated out of line as required…
Though that was not part of the polygon function…