joining two board of 3/4" plywood w/out bumps

[Alex]

Another poster had mentioned raised bumps on the surface of plywood, just above where the screws would have poked out of.  Is there any way to avoid this?

[Tim Grace]

When you set the stop collar on the drill, the shoulder on the bit should be just shy of the mark for the plywood you are joining.  Most plywood is no longer the real dimension, but is about 1/32nd shy.  What is sold as 3/4" is actually about 23/32", 1/2" is actually 15/32", etc.

[joseph joel]

I experienced the bumps when i first started using my Kreg Drill Guide also. Things to do to avoid it:

1. MEASURE YOUR WORKPIECE. Size does matter (rimshot!). Successful use of Kreg's PH system is dependent on ACTUAL not the NOMINAL size of your workpieces. 
2. Your work piece's size determines 3 key elements: 1. the screw LENGTH, 2. the appropriate DRILL GUIDE setting, and 3. drill bit STOP COLLAR setting. In general, follow the SETTINGS guide included with your jig ensuring all 3 are followed. 

3. IF your workpiece measurement doesn't match Kreg's settings guide exactly, round DOWN to the next smaller size and use that as your workpiece measurement.

hope this helps.

[KregRep]

Plywood tends to be a little undersized. Adjust your depth collar slightly. This will shallow up the hole, which will not allow the screws to drive as deep.

[Alex]

Thank you to all the fellow woodworkers that replied.  Your answers are very helpful.  I'll give it a shot!