Quick answer - size for holes

[cholin]

I realize you should use 1-1/8 bit, but instead of buying one, can I use 1-1/4?  its like 1/8 inch difference, shouldnt cause any problems...does anyone know?

[SirPeale]

Yes, it's too big.  Don't do it.

[IMMark]

I agree...don't do it
You can get a 1 1/8" spade bit, very inexpensive, or a entire set for $5.
When you use them, drill from both sides to prevent blowout.
Drill from front until, the point breaks through, then finish from the back side.  A hole saw gives a better cut, and is more expensive.  But if you use a spade from both sides, results are more than addequate.

[cholin]

Alrighty Ill look for a spade bit.