#1: Yeah, you were given bad info. A 6-32 needs a tap drill of .1065, not .15. You need to be up in the #10-32 size for a .15 hole.
Here's a link for ya:
http://www3.telus.net/public/aschoepp/tapdrill.html
#2: quit converting it to metric. You need to face the reality that you now live in the backwards united states of america. I gave up on using metric a long time ago, 'cause you just can't find them in ready quantities locally.
Losi 8T 1.0, Savage Flux - XL style, LST XXL, Muggy, 3.3 E-Revo Conversion and sitting outside 425hp, 831 Tq Dodge Ram Turbo Diesel. It SMOKES