10 PSI at 40F will give you 2.3 atmospheres of CO2 in about 5-7 days, which is comparable to a standard commercial ale (2.2-2.6 or so). If you aren't getting any carb, either your temp might be high or you have a leak.
Are you seating the o-ring seal by hitting the keg with 30 PSI before you bump down to 10? If not, you might have a slow leak right through the top. Those are hard to detect, but they'll ruin your carb!
Primary #1 - Midnight Ryeder (Midnight Wheat and Rye)
Primary #2 - Florida Weiss
Primary #3 - Kane-DOH APA (Honey Citra APA)
Secondary #1 - Downtown Flanders Brown (brewed August 2012)
Keg #1 - Raspberry Florida Weiss
Keg #2 - Cinnamon Raisin Cider
Keg #3 - NONE!
Bottled - NONE!