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Author Topic: SRX828p - at my wit's end!  (Read 19174 times)

Bob Leonard

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Re: SRX828p - at my wit's end!
« Reply #60 on: October 15, 2015, 07:15:31 am »

Sorry but i must disagree with Bob and some others here.
Tnuts should not be easy to push back if they are secured as they should be.
So this is just very poor and unprofessional mounting of tnuts there by JBL.
Here is how it should be done.
On the subs we are putting two screws.

If you used high retention "T" nuts instead of those 8 sided "T" nuts you wouldn't need the sheet rock screw. And to be honest, the use of the sheet rock screw makes the assembly look as if you're repairing a problem vs. attempting to eliminate one. If you used a "T" nut such as the one at the link below you'll eliminate the screw, the worry, the labor, and lower cost while providing a more professional look and appearance of quality.

http://shop.stafast.com/t-nuts/locking/ultimate-locking-rivet
« Last Edit: October 15, 2015, 07:21:10 am by Bob Leonard »
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BOSTON STRONG........
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George Friedman-Jimenez

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Re: SRX828p - at my wit's end!
« Reply #61 on: October 15, 2015, 09:23:29 am »

First off, Bob, your previous post is one of the best written posts I have seen on this forum. Real useful information on a common problem few people really understand in depth from someone who really knows a better way. Hopefully JBL is reading along and considers revising their production process based on your advice. Thanks.
Second, I see a flange on the photo of the T-nut, which looks like it is part of the design to address just the problem we are talking about, retention of the T-nut after installation. It looks like that flange gets created after installing the T-nut. Is this just done by banging a countersink in the open side while securing the T head from being dislodged? Or is there a special installation bolt that creates the flange when tightened, while keeping the T-nut in place, and is then removed?
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Debbie Dunkley

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Re: SRX828p - at my wit's end!
« Reply #62 on: October 15, 2015, 11:05:43 am »

I used T Nuts when I made those dolly boards a few months back. I can't remember what type they were but I must admit, I didn't give that part much thought- I just went to the store and purchased what looked right for the job.
Once I drilled and hammered in the T Nuts into the back of the board, there is no way they could have fallen out or ever will.
In fact, in the past, I have attempted to remove them and found it difficult  so like Bob said, it has to do with the style of T Nut ( and perhaps quality?)...
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Tommy Peel

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Re: SRX828p - at my wit's end!
« Reply #63 on: October 15, 2015, 11:37:25 am »

Geez Bob, all these years I thought you were supposed to balance the screw on the head of a electric drill motor, run it up to full speed with the clutch disabled, ram the screw in the hole and then strip the shit out of the head as it goes in.

The other variation of this technique when using machine threads is to cross thread the fastener then use the power of the tool to strip the threads while concurrently stripping the shit out of the head, hoping the fastener snugs up before it is destroyed.

This also provides extra work for the poor SOB that has to take it apart and when done in racks in data centers really pisses the boss off.

It also provides much humor to watch someone use this technique to secure the first screw of a speaker driver while the cabinet is still vertical.  This requires the extra skill of supporting the weight of the driver while getting the screw to bite into the wood (because all the t-nuts are stuck to the back of the driver after you pushed them out) without ramming the fastener through the cone.

I recall another version of this technique from my days working in a tractor shop as a mechanic. It involved a 1/2in or larger air powered impact driver destroying the threads in a tractor frame while installing a front end loader mount. They'd just hope the bolt went down tight and flush before the destroyed threads stopped the impact driver.

Then again sometimes the threads were in bad shape to begin with and would cause problems w/out cross threading. At one point I remember the assembly guys were running a tap down all the loader mount threads before putting the bolts in to prevent problems. Then the shop foreman would complain they were taking too long.... Always time to go back and fix it but never enough time to do it right the first time.

</thread_side_track>
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Marjan Milosevic

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Re: SRX828p - at my wit's end!
« Reply #64 on: October 15, 2015, 12:01:53 pm »

Bob, i am not aware of anyone using those tnuts.
By looking at it i can assume that the process of installing them is much longer then simply hammering the tnut.
For me wood inserts are much more elegant solution. But also more time consuming.

Steve M Smith

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Re: SRX828p - at my wit's end!
« Reply #65 on: October 15, 2015, 12:34:20 pm »

I would think T nuts would be stronger than those inserts as they have a flange behind the panel.  The inserts break up the panel around the hole.


Steve.
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Bob Leonard

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Re: SRX828p - at my wit's end!
« Reply #66 on: October 15, 2015, 01:01:40 pm »

Bob, i am not aware of anyone using those tnuts.
By looking at it i can assume that the process of installing them is much longer then simply hammering the tnut.
For me wood inserts are much more elegant solution. But also more time consuming.


Marjan,

The inserts you show above were designed for particle board and are usually used with the type desks and furniture you assemble yourself. They are not made of steel but are made from "white metal", a cheap type of pot metal. They really have no load bearing strength and I wouldn't trust them for much more than a particle board desk.

Follow the link below and you'll find an insertion tool for the high retention "T" nuts. Insertion time with a drill should be less than 10 seconds per nut. Be sure you match the tool to the nut.

LINKY
« Last Edit: October 15, 2015, 01:28:29 pm by Mac Kerr »
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BOSTON STRONG........
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Marjan Milosevic

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Re: SRX828p - at my wit's end!
« Reply #67 on: October 15, 2015, 02:30:44 pm »

Bob, that will probably work with those tnuts you showed us. Not with a "normal" tnuts that has a quite shorter length.
As for the inserts, i do use them for the pole cups, and they are made out of steel, not the metal you mention. So there are more types. So if you screw it to the baffle from the inside it holds very good.

Debbie Dunkley

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Re: SRX828p - at my wit's end!
« Reply #68 on: October 15, 2015, 04:14:53 pm »

I called JBL again a little while ago as I hadn't heard back after leaving a couple of messages and sending 2 emails??
Anyway, this time I spoke to Sam who told me to go ahead and remove the woofer to get that TNut back in... Lots of apologies etc etc.....
Won't have time before the weekend so I'll finally get to use it Saturday (yay) and then pull out the driver on Monday or Tuesday. Sam asked me to send photos of everything once I am in there so I will. He said he is head of Quality and was interested to hear everything I had to say.
Looking more and more at that T Nut, it really is poor quality - the prongs are quite short and thin compared to those I have come across and used my self in the past.
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A young child says to his mother, "Mom, when I grow up I'm going to be a musician." She replies, "Well honey, you know you can't do both."

DavidTurner

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Re: SRX828p - at my wit's end!
« Reply #69 on: October 15, 2015, 05:10:28 pm »

Yes, but we call braces suspenders. So over here it would be "belt and suspenders". BTW what you call suspenders are called garters here.
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Re: SRX828p - at my wit's end!
« Reply #69 on: October 15, 2015, 05:10:28 pm »


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