If you've master keyed Schlage over the years, you've dealt with the situation where you needed to use a #1 master pin.  There's not an ideal solution, but I've used this work around over the years, and it works on most Schlage Residential locks.  Whenever possible, change the keys, so you can use a #2 or larger master pin.  I recommend that you only use one .020" master pin per lock. 

This set includes a half pack each of bottom pins that are .003" smaller than the normal Schlage bottom pins, and a full pack of .020" master pins.  Change the bottom pin ONLY in the hole where you need a #1 master pin.  Instead of using a .015" master pin, you can now use a .020" pin, which is less likely to bend and jam than the regular pin.  Sometimes it will result is a slight catch or minor tightness, but generally it works fine.  The .020T pin is not crowned or thinner at the edges, so it is safer to use.