Bfowler's Big Bad Box Building Butorial, er, I mean Tutorial

bretti_kivi · Post by **bretti_kivi** » Sat Oct 11, 2008 9:52 am

There is actually something even better than T-Nuts. They're called "threaded inserts". Advantages:
- you drive in from the front - you don't have to see the rear
- they're not at physically big
- you can drive into a right-angle and therefore use them to build your box.

examples: http://www.insertsdirect.com/productCat ... 08dc80b4b6

See also http://www.diymobileaudio.com/forum/sho ... ed+inserts

Bret

Post by **Bfowler** » Mon Oct 13, 2008 8:04 am

ah, i have seen those. i will give them a try on the next build

bretti_kivi · Post by **bretti_kivi** » Mon Oct 13, 2008 8:36 am

you want a hundred or so? If you can get M4 screws, I can get some sent over. I just bought a large box, so....or, if anyone else wants, ask!
Bret

Post by **Bfowler** » Mon Oct 13, 2008 8:57 am

that's a sweet offer...but it would probably cost more to ship them then to just by them local.

thanks though!

gkitching · Post by **gkitching** » Mon Oct 13, 2008 9:09 am

F-That! Treaded inserts really are no better then just using a big screw. They can rip out just like a screw. Plus the biggest pita with them is that if you crossthread the screw going into the threaded insert, they will just twist right out the back of the piece. Then try to get that screw out! With the threaded insert cross threaded and stuck on the tip of the screw and the screw head on the other side, your only option is to cut it off. Then compound that with a free spinning screw and trying to hold it in place while you try to cut it off. ..

Sorry, speaking from experience and my experience is there is no replacement for t-bolts when it comes to wood. A t-bolt will inherently work better the more it is tightened. A treaded insert will still rip out after a certain point. The only use for threaded inserts might be if they are used in a situation where a screw would be taken in and out frequently and a normal wood screw would chew up the wood over time. Even then a t-bolt is still better! ... Not even close!

Post by **Rold Gold** » Mon Oct 13, 2008 9:31 am

Those inserts offer a strong resistance against pull-out.....

I'm the KING of the pull-out......except for twice......

gkitching · Post by **gkitching** » Mon Oct 13, 2008 9:40 am

Keyword being 'resistence' to pulling out. They will still pull out. And can easily be twisted right out the back of your work. A t-bolt will NEVER pull out. You will strip the threads and/or head long before breaking off the 'T' of a t-bolt.

Mechanically inferior!

bretti_kivi · Post by **bretti_kivi** » Mon Oct 13, 2008 10:01 am

... I would agree that T-Nuts are sometimes good. My experience with them is all bad.
Mainly because you have to have a full hole and you really really ought to have anchorage for them to 100%. I can't do that frequently - especially with smaller drivers. How many drives does it take to chew the thread off of Chipboard, MDF or ply? 4? 5? it's not many... I like these because they work, for me, in my situations, which normally involve holes that have zero clearance round the edge and places where I don't want to put a woodscrew. I don't think I've actually ever been happy with the fixing a t-nut has given me. yes, I have enough, and yes, I'll agree, they are going to be stronger, but who's likely to find this out?

"Use the correct fixing for the job", is a good maxim here, maybe?

Next question: Do you glue your T-Nuts in place?

Bret

gkitching · Post by **gkitching** » Mon Oct 13, 2008 10:49 am

bretti_kivi wrote: ... I would agree that T-Nuts are sometimes good. My experience with them is all bad.
Mainly because you have to have a full hole and you really really ought to have anchorage for them to 100%. I can't do that frequently - especially with smaller drivers. How many drives does it take to chew the thread off of Chipboard, MDF or ply? 4? 5? it's not many...

With a t-bolt you never rely on the edges of the wood. Compression is the force used to secure.

bretti_kivi wrote:I like these because they work, for me, in my situations, which normally involve holes that have zero clearance round the edge and places where I don't want to put a woodscrew.

I think that comes down to pre-planning. Of coarse every situation is different and sometimes you're forced to stray from your plan. But when it comes to building sub enclosures, there is almost always room for a t-bolt.

bretti_kivi wrote:I don't think I've actually ever been happy with the fixing a t-nut has given me. yes, I have enough, and yes, I'll agree, they are going to be stronger, but who's likely to find this out?

Anyone using them for Subs! Which is the purpose of this particular thread.

bretti_kivi wrote:"Use the correct fixing for the job", is a good maxim here, maybe?

Next question: Do you glue your T-Nuts in place?

Bret

Most t-bolts have a 'grip' of some sort that will embed the 't' into the back side of the wood. Keeping it in place and keeping it from spinning. I will typically 'set' a t-bolt first by driving the screw into it and compressing the t-bolt into the piece of wood before I actually mount something with it.

Sorry if I sound critical on this point but I curse those f-ing things everyday I'm at work. My displays are such that each piece of equipment is mounted to a 'card' that in turn is secured to the display via these threaded inserts. They come out all the time, get cross threaded as described above and chew up the wood just like a screw does anyway. I've wasted countless hours trying to repair them and just have gotten to the point where I swear if I ever meat the guy who invented them I would be compelled to bitch slap him!

KHPower · Post by **KHPower** » Mon Oct 13, 2008 1:41 pm

I had a problem when I went to unload my driver. 1 out of the 8 tnuts I set acted up towards the end of the uninstall and totally ripped to shreads a 2 in space on my front baffel. I easily added a new front baffel but this may have been becasue I used the ace hardware t nuts with allen screw bolts to hold up a 50 pound driver

vwguy3 · Post by **vwguy3** » Mon Dec 07, 2009 7:59 pm

Why the foam around the box? Nice job on the box building. I think I might use that type of wood on my next box build.

deathcloud · Post by **deathcloud** » Mon Dec 07, 2009 8:10 pm

I am using that type of wood cuz I am getting it for free. I am stoked. This tutorial gave me hope. The only thing that I lack is a router to get that perfect circle.

I am still not understanding what the T-Nuts do. I usually just get regular screws and screw them into the sub box to mount the sub. What else do you have to have to hold the sub in? Someone explain this to me?

deathcloud · Post by **deathcloud** » Mon Dec 07, 2009 8:11 pm

Oh and can we see pics of it stretched out with the faux material

Post by **Bfowler** » Mon Dec 07, 2009 8:25 pm

the foam around the box was used to create a baffle separating the trunk from the front of the cone so i wouldn't get wave cancellation while firing the sub forward.

that worked....but i then became plagued with the the clasps for the folding seats rattling like crazy.

i was never able to cure that, so i went in a completely new direction

http://phoenixphorum.com/what-brian-has ... 10322.html

thats as far as i got...and now i i ripped the system out of that completely and am trying to sell the bmw

the tnuts give you some thing more solid to screw into to mount the sub.

bolts actually thread into those so its basically imposable to strip out the holes

deathcloud · Post by **deathcloud** » Mon Dec 07, 2009 8:30 pm

Oh ok so I screw in the t nuts into the wood where the mounting holes for the sub are. Then after I do that I line up my sub where the t-nuts are and screw in another set of special t-nut screws that thread into the t nut hole? Is that correct? I really want to do this for my box build...

As far as getting the wiring to the sub I guess I have been reading that doing two drilled holes into the box and having the wire come out is the best and just filling it with silicone or something. Even though the way u did yours looks more professional/nicer.

Post by **Bfowler** » Mon Dec 07, 2009 8:47 pm

i REALLY like my bolt stlye ones i used in the tutorial....STILL

i have made several boxes with them and love them

to use the T nuts.

-set your sub in/on the hole

-use a sharpie to mark the hole locations

-drill out the holes

the tnuts go in BACK of the holes. you can press them in with a c-clamp

now, when you thread a BOLT threw the front of the hole it threads into the tnut. (they arent special bolts. just normal home depot bolts that are the same threading)