attaching front baffle without screwing

Hello all,
I am building a speaker box where I want to make front baffle removable. The baffle will hold two 12" or 15" or 18" woofers so it will be heavy. baffle is either 18mm or 25mm think MDF. As it will be removed for several times, I am afraid the screw holes will loosen up. I want to know what alternate methods available other than screws? I can think of using D-nuts or T-nuts. Any other options available?
Thanks
Shiva
 
Hi Shiva,

I modified a set of speakers that had the 15” woofers screwed into chip board with wood screws. Some folks just keep rotating the woofer so that you make new mounting holes. This just makes the chip board become even less secure and fracture more.
I made some 1/4” backing out of plywood glued it to the inside around the woofer to attach some 6-32 t-nuts so I could use machine screws to attach the woofer.
 
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Use oak for the parts of the box that receive the screws from the front baffle, then drill and tap the oak for a fine thread machine screw, like an M5 or M6 x 0.75.
Make the tapped hole about 15 mm deep and you will have a very strong, durable joint that's easy to open. This is easier than t-nuts and takes less space. Oak is incredibly tough and takes machine screws very well. Photos are from my last sub project for the rear connector plate and to mount a 12" subwoofer that weighs 11 kg. I have also tapped plywood and MDF for machine screws with no problems, but obviously they are not as strong as oak. Gave up on wood screws for speaker construction a long time ago.
 

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...18mm or 25mm think MDF ...

Dont think MDF. Think birch plywood instead if you really want and need to move and remove this very part over and over again: MDF is brittle and will get ugly over time, birch plywood is not and will not. And screw it altoghether. If you really stick to an alternative method, then consider using tightening straps (no kidding!) until you do not need to remove the front baffle once again. And by then, you may screw or even glue it. Or even better and for best robust results: Screw AND glue it. As my personal and general rule, it is a good practice to to design around the necessity to remove a front panel right from the begin.
 
When I use MDF in situations where I want to remove drivers occasionally, I apply Weldbond (essentially a strong PVA glue) on the self tapping wood screws I use, then run the screw in and out a few times and remove it, letting the glue dry in the hole and cleaning the screw in water and setting it aside. Then when the glue is dry, the threads in the hole are fairly resilient compared to non-treated MDF. I then put a very light amount of silicone grease on the screw thread to stop it 'picking up' on the glue. I use just enough glue to coat the sides of the hole.

Of course, the key is to be careful when tightening them to avoid stripping the thread in the MDF.
 
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I give up.
You are getting advice that either doesn’t apply, is using words to describe what you have already suggested, is implementing things unnecessary or are more complicated than need be.
This is not the case with all posts, but how are you supposed to weed through it all?
I know the members want to help but this thread strikes me as strange.
I am not a Mod right now, I am a just a construction guy with decades of experience.
 
The front baffle is the part you most want to be securely fixed to the box, I worry making it removable is asking for vibration issues - the moving mass in large drivers is substantial and that directly imparts momentum to the baffle. If you can make the back removable instead that's going to be less of a compromize. You also have to make an air-tight seal (at audio frequencies at least), which means either glue or some sort of sealing strips.

MDF has one virtue for speakers, its less resonant that plain wood, ie its quite well damped acoustically - it doesn't ring so much, which can mean avoiding/reducing colourations due to cabinet resonances. It is soft and screwing into it ideally requires T-nuts and cup washers to spread the load - its best screwed and glued for the extra strength and sealing, and should be painted to both make it air-tight and to prevent it getting wet (it will swell and weaken very quickly if wet).

Chipboard someone mentioned - rather crumbly and not sure you can get glued joints decently air-tight? I worked with OSB once and it had the same problem - although that was for a unit destined for occasional outdoor use.

And it shouldn't need saying - use a mask when working on MDF (or any woodworking generating dust), preferably work outside if you can.