What size keps nut?

[Mars-Hall]

What size keps nut should I order for mounting speakers in my 70 SFSR, #4, #6 or #8?

[eleventeen]

They should be #8. They should be the same thread as the nuts on the long screws that hold the chassis in. 

Kep nuts are wonderful things, but don't forget they will scar the point on the speaker where they tighten down. The mounting holes through a speaker frame are not exactly small. If it were me, I would place some ordinary flat washers between your kep nuts and the speaker frame, for sure. And if it's a Twin and you are going to blast it, I might put a drop of nail polish or lok-tite on the threads. 

[stratele52]

Yes they are # 8 but sometimes when I made cab I use #6,  easier to install speakr on