Attaching Piezos to plywood

[Cooltone]

Hi All,
A real newbie question. I have looked for answers on the forum but couldn't find one.

How do you fix the tweeters to the horn sides? The tweeters I bought didn't come with any fixing accesories (washers etc). I have a 1/4" hole in the tweeter which is 3/16" depth to fix into 12mm (nearly 1/2" plywood).

Countersunk screws don't seem to be great and neither do flange-head self-tappers. I've been searching for about 3~4 weeks and not found a solution What combination of screw types and washers do you consider best?

I'd like to be able to replace the tweeters if one goes down.

(My plan is to use a gasket to seal the tweeter edges.)

Apologies in advance for the complete newbieness of the question.

Cheers,

[Seth]

You can certainly use whatever you want. I bought Truss Head Screws for mine.

"Parts Express #8 x 1/2" Phillips Truss Head Screws 100 Pcs." https://www.parts-express.com/8-x-1-2-P ... s.-081-480

[Bill Fitzmaurice]

Those work well, but they rust. Before using them I stick them into a piece of styrofoam closely spaced and give them a coat of black spray paint.

[Cooltone]

Many thanks. I was close with flange head self tappers, but so far with 3.5mm (No 6) x 10mm.

Cheers!