driver mounting(rs180 & rs28)?

[cgr]

When I built my sub I glued small squares of plywood to the interior of the baffle so that the t-nuts would have something solid to bite into.

Do I need to do something similar to mount the rs180 and tweeter? I'm assuming that wood screws in MDF won't hold as well if I have to take the driver out to adjust stuffing or crossover?

[Chris7]

I would use T-nuts for the RS180. Wood screws are fine for the tweeter. There is little pressure, the tweeter is rarely removed anyway, and one or two removals will still hold in MDF.

[Jim85IROC]

I'm not a fan of t-nuts. I always have better luck with hurricane nuts.

Unlike with flush mounting a sub, you should have more than enough wood left on a 3/4" baffle to fully sink a t-nut or hurricane nut and have plenty of strength.

I have to admit though, that with most of my installs, I just use #8 1" screws from Parts Express. I drill a 7/64" pilot hole in the wood, and then drive these in. I've had drivers in and out a few times with no problems. The #8 are far less prone to stripping than the #6 screws, and if you've got the good brown-ish MDF instead of the yellow crap, you're not likely to ever strip a hole. Then again, my driver cutouts are usually snug enough that the drivers stay put without any screws at all.

[Eric H]

I'm not a fan of t-nuts. I always have better luck with hurricane nuts.

Just the opposite for me. IMHO hurricane nuts "blow".

[Chris7]

Just FYI, if you're looking for Hurricane nuts at your local hardware store, they're called Propel nuts. "Hurricane nut" is a Parts Express marketing term. I generally prefer Propel/Hurricane nuts with MDF.

[Brian Bunge]

I use the #8 screws from PE for all but the largest subwoofer drivers. And then I used threaded inserts with machine screws. I won't use T-nuts and haven't had a real desire to try the hurricane nuts.

[Eric H]

To clarify, I was referring to the PE hurricane nuts. I have no experience with the propel nuts.

[gimpy]

I am not a big fan of t-nuts in mdf. I have one loose (at least only one that I know of) t-nut in one of my speakers and can not get it to tighten or loosen. I do not know how to remove it without going through a very difficult and time consuming process of loosening and removing all of the screws/t-nuts on that one speaker, which I do not want to do.

Since that one, I have used "hurricane" nuts from P.E. without any "known" problems.

The mdf is too hard for the prongs on the t-nuts to really dig in and catch it, I think. It bends the prongs down and they can't catch (in some instances), whereas, using something softer, such as plywood, would be a better choice for using the t-nuts, I think.

So, I would continue to do what you are doing if using t-nuts/mdf combination.

Good luck, Frank

[JonP]

Drilling the right size pilot hole is crucial for best thread strength... probably also for hurricane nut "bite" and hold...

I've done a few things to help matters with both situations. For screws into MDF, I've run thin (1lb cut) Shellac into the hole a few times, it soaks in and hardens the thread area. I'm a big fan of slathering MDF with 1lb Shellac for sealing purposes anyway... Give it enough time to fully dry, or it will be softer than normal, but after, it seems to give some extra strength to the threads.

On the T/Hurricane nut situation, I've wet the MDF and the back of the nut with 2 part Epoxy before hammering them in. It adds extra strength to prevent them moving and starting that deadly loosening process.