drilling with a spade blade

[OWC Jamie]

One other suggestion since you need to drill at angles - drill in a little bit straight / flat, THEN change to your 45º angle. Starting any bit not flat will cause it to jump a bit because you will only be drilling with one extreme edge of the bit. This way you'll keep the wood from chipping out as much - a Forstner bit will shave the surface and cut a nice clean round hole immediately. Only saying go in 1/8" or so flat and then change to the 45º. Trust me it'll work better.