Reason Criterion Square Boring Head Exists?

What is the reason for the square boring head that Criterion makes? What advantage does it have over the round Criterion boring head? Jon Banquer San Diego, CA

On Sun, 10 May 2009 13:18:30 -0700 (PDT), jon_banquer
  Quoted Text Here  
You mean other than range, bar holder positions and versatility?
http://www.criterionmachineworks.com/Pages/tech/boringheadinfo.htm
Put the two of them side by side, what's the difference? Item #4 is the hint, three set screws equals three tool positions.
http://www.criterionmachineworks.com/ look at the tool
Turn the cutting edge 180° and what do you think can happen?

http://www.youtube.com/watch?v=y0NXQLz8r0c&feature=related
(Not criterion but you should get the idea.)
You now have an OD Turning tool.
-- Tom http://tinyurl.com/5okkgz

How to make a Boring Head;
http://homepage3.nifty.com/amigos/boring_head/boring_head-e.htm
http://homepage3.nifty.com/homeshop-tools/boring_head/boring_head.gifhh

The maker of the mentioned boring head has a website of a wide variety of very interesting tooling made for his(?) home shop machines.
Here's the english-version link http://homepage3.nifty.com/amigos/index-e.html

  Quoted Text Here  
http://homepage3.nifty.com/amigos/knurl2/round2.wmv

wrote:
  Quoted Text Here  
Just be sure and use a rh boring tool or else the shank might come unscrewed from the head

Brother Lightfoot wrote:
  Quoted Text Here  
You got it backwards. The head might come unscrewed from the shank.

wrote:
  Quoted Text Here  
unscrewed
Oop sorry bout that.

I think the reason they are still offered is some machinists think they are more rigid than the round ones.
Jon Banquer San Diego, CA

jon_banquer wrote:
  Quoted Text Here  
Sounds reasonable to me. A 3" square head has more sliding surface contact area than a 3" round head.

  Quoted Text Here  
With only one boring bar hole instead of three I would guess this would also help.
Jon Banquer San Diego, CA