[Zuman]

Hello, all. I'm building my first pair of DIY speakers, the Criton 2TD-X flatpack from CSS.  The kit comes (I believe...it hasn't arrived yet) with tapping screws for mounting the two 7" midwoofers right into the routed cutouts in the MDF. However, I'm going to be experimenting with NoRez, fiberglass fill, and eggcrate foam, so I expect to be removing the drivers a few times to access the damping until I get the sound I want.
So...those of you with cabinet-building experience: would you recommend that I use t-nuts or some other kind of inserts rather than screwing directly into the MDF?
Thanks!

[Peter J]

I suspect at least one difficulty you might have with either is proximity of mounting hole to the through hole for the driver. MDF just isn't strong in a scenario like that. I have successfully threaded MDF to accept machine screws by first threading the hole then putting a drop of cyanoacrylate (super) glue in hole, letting it cure and then running the same tap through it again. A drop is all that's needed, just to wet the fibers, not swamp the hole.

T-nuts would be my last choice outside of super glue. A skinny screw-in insert might work. I've even tried Heli Coils, but seemed like a lot of work to get what functioned the same as super glue.

[jtwrace]

This should help:


https://www.audiocircle.com/index.php?topic=149780.msg1820760#msg1820760

[Zuman]

Thanks!

[S Clark]

And if you want to compare egg crate, fiberglass, and No Rez, do the No Rez last.... it has an adhesive backing.  But there is no comparison as far as deadening the cabinet. No Rez is far better than the other two. 

[jules]

T nuts should be fine. You can get stainless steel ones, which are useful since plain ones do tend to rust over time. If you're being extra fanatical you could use stainless bolts and a little anti-seize to make sure you don't have any problems later. Oddly, stainless fasteners can bind in theory, though I've never seen it happen myself.