Can I get a 3/8th inch collet for the 1400?

Yes, it's Festool product number 494464. Link below.http://www.festoolproducts.com/festool-494464-3-8-in-clamping-collet-with-nut-for-of-2200-of-1400.htmlIt comes with 1/4", 1/2" and 8mm collets included.