So hey guys.. my first post here but I've been reading for some time.. Anyway, I was flying the other day and 3 of 4 of my mounting screws that hold the motor to the firewall somehow vibrated themselves loose in flight.. anyhow, my local home depot doesn't carry a screw that will fit, any suggestions? I live in Chicagoland and my work schedule doesn't let me make it to the hobby shop.. is it just a standard dubro screw or is it some Sig special? Thanks all,

Sachin

My 4* 40 manual isn't handy, but my 60 is. The four mounting screws are M4x22. That's 4mm in diameter and 22mm long. I bet they provide the same screws for the 40 size. Lowes has 4mm screws, and almost any auto parts or hardware store should have them also. Measure the remaining screw you have. It should measure .160" or about 5/32" if it's 4mm. If it's 22mm long, that will be about 7/8". You should be able to get Allen head 4mm screws at a larger hobby shop. That would be a step up from the Phillips head Sig gives you.

And put blue loctite or another brand of thread-locker on them next time.