I'm using a custom Wiremold ceiling fan box to surface mount a Harbor Breeze ceiling fan onto a wooden beam. Problem is -- the Harbor Breeze mounting bracket does not have compatible screw pattern holes that allow the bracket to attach over the Wiremold screws extending from the mounting plate and the fan box cover.
The customer wants to continue with the same fan (instead of changing to a fan with compatible mounting bracket), so after brainstorming, I figure I could simply make my own mounting holes in the Wiremold cover and mounting plate. I would the run screws through the mounting bracket, the Wiremold cover, and the metal mounting plate -- and ultimately secure everything directly into the wooden beam.
I believe the machine screw size that typically is used is #10-32. Since my custom holes will need to secure into wood -- I'm assuming I go with a more aggressive (coarse?) screw type.
Question is: What is the ideal screw I should use in this scenario? Also, should I pre-drill the holes or will a self-piercing screw work? Also -- any advice on screw length , or brand, or any other solution to solidly secure everything are welcome.