I recently agreed to build a couple of bedside tables for a buddy of mine. He wanted something constructed of cherry to match his bed.
He wanted to pay me fair market value but I insisted that he just pay my lumber bill (with 50% extra purchased so that could be picky about grain selection and still be left with a modest bonus to my inventory.
Since I would not accept "payment" he bought me a the 12" Starrett combination square with the center-finding and protractor heads as a "tip".
I have found that I use it as a marking guage in conjunction with a making knife. I can set the gauge at, say, 1" and easily "split the line" etched on the rule. This was not possible with a cheap combination square as the head would not lock really well, and the graduations were tougher to read in chrome.
The only problem I have found with useing the combination square is this way is that it is a bit back-heavy when marking a small offset like a 1/4". This got me thinking that I would really get enjoy using a smaller double square for many of these tasks.
Starrett makes a 4" double square for about $50. I am sure that the readability and overal build quality will be essentially identical to my combination square. Lee Valley makes a 4" DS that "appears" very similar.
Thanks,
Steve