Milling a square drive

[BWS Arms]

Is there a formula to determine what size I should turn my round stock to mill a .550" square? The .550" is across the flats measurement.

 

[BWS Arms]

I found a formula but I dont know if its point-to-point or across the flats? The formula is: Round Bar Diameter = Square Diameter * 1.414214

 

[Asm109]

Formula is Distance across the flats * square root of 2 (aka 1.414)= Bar diameter.
You probably want to cut the diameter a bit smaller than the formula says so the corners of the square are not dead sharp.

 

[mmcmdl]

A squared + B squared = C squared Pathageriams theory or something like that . You're looking for the hypopotamus !

 

[markba633csi]

 

[piper184]

Just don't use πr²

"Pie are round. Cornbread are squared" ~ Junior Samples, Cornfield County

 

[tjb]

What are you making? Do you want the diagonal of the square to be equal to the diameter of the round stock? How long will the finished product be, and what portion will be round / what portion will be square? These specifics may influence how you machine it.

Regards

 

[BWS Arms]

I found what I needed. I really should have paid more attention in math.

 

[MrWhoopee]

I found what I needed. I really should have paid more attention in math.

Whoda thunk it would actually be good for something?
While you're at it, better brush up on your trig.

 

[RJSakowski]

For sharp corners, the diameter is 1.414 x the distance across the flats. If you are going to fillet the corners, the diameter can be slightly smaller, depending upon how large the fillet.