T-Nut Alternative?

[Charles218]

As I prepared to mount the tweeter in my 3A, I found that the upper T-nut was loose and not griping the particle board, this caused a bit of difficulty when I removed the tweeter. It appears that the particle board is slightly damaged right where the T-nut goes and I am concerned that I will make it worse by installing the T-nut. My only thought was to remove or bend the spikes out of the way, and glue it in place. Are there any alternatives to T-nuts, or any other suggestions on how to proceed?

[DavidR]

get some good wood epoxy and 'cement' it in place

[ra.ra]

Hi Charles, glad to see you active in the forum again. IMO, the T-nuts are a great little detail with vintage AR speakers, but when they lose their grip they can be holy Hades to deal with. When they work themselves free, the teeth may need to be straightened out before re-insertion, and as David mentioned, the use of added epoxy around the shaft is crucial for longevity. The particle board used for baffle panels is most definitely of various qualities, and when you run into the inferior chunky-style as I have recently, this is what may happen when a T-nut is placed too close to the inner edge of the cut-out. This situation has not been fixed yet.

When re-installing, the most important thing is to get the positioning spot-on so that all male machine screw threads can properly align with female threads of the T-nut. Sometimes I use a template to ensure accuracy. 

[Charles218]

David & Ra.Ra,

Thanks for your feedback, I'm not a real pro at these and I know when it's time to seek advice from all of the experienced folks on this forum. I did go ahead and add a bit of epoxy earlier this afternoon, though I suspect that I did not use enough as it did not hold. I just tried again with a stronger glue, and this time I added it around the shaft rather than on the flat piece were the prongs are. I will let it sit overnight and see what I have tomorrow. After putting it in place with the glue, I installed a screw, my hope is that the screw will give it the proper alignment.

Ra.Ra, I have not been very active here lately, not for a lack of interest but rather because things seem to be more hectic. I expect that within the next couple of years I will be retired and able to choose what I want to do with my time.

[genek]

I would drill a new set of holes offset about 10 degrees from the originals and then reset the nuts. That shouldn't shift the drivers around to the point that the leads are too short to reconnect.

There are also round flange nuts that mount with small screws, but you might not have enough intact material around the original holes to use them,

http://wedo.hillmangroup.com/item/steel-nuts/nuts-washers-stainless-assortments/4141

$24 for a pack of 15 at Home Depot.

[DavidR]

12 hours ago, Charles218 said:

I expect that within the next couple of years I will be retired and able to choose what I want to do with my time.

I hope you are BUT I found that I ask myself how did I ever find time to work and I even gave up one of my hobbies that I thought would expand.

[Charles218]

Genek - The flange nuts that mount with screws appear to be a good alternative to the OEM spiked version. My reluctance to install the original nuts had to do with the amount of force required to get the spikes to penetrate the wood. A small pre drilled hole for mounting screws would put much less stress on that very delicate section of the baffle board.

For now, I am okay as my second try with epoxy has worked, and I have successfully mounted the tweeter.

[ra.ra]

Next time this issue comes up in my projects, these hurricane nuts might be the solution.

https://www.parts-express.com/parts-express-8-32-hurricane-nuts-50-pcs--081-1080

(Edit: adding image of various H-nuts)

Edited December 13, 2018 by ra.ra
added image

[Stimpy]

3 hours ago, ra.ra said:

Next time this issue comes up in my projects, these hurricane nuts might be the solution.

https://www.parts-express.com/parts-express-8-32-hurricane-nuts-50-pcs--081-1080

Nice suggestion ra.ra.  But one question, do the PE hurricane nuts have the same thread count and pitch as our AR T-Nuts?  I guess I'm not sure if this is a standardized thing?

Thanks!

[DavidR]

54 minutes ago, Stimpy said:

Nice suggestion ra.ra.  But one question, do the PE hurricane nuts have the same thread count and pitch as our AR T-Nuts?  I guess I'm not sure if this is a standardized thing?

Thanks!

I bought some stainless steel  button allen cap screws  from MSC because lots of my screws on the 10Pi and 9's were rusting. The size was 10-24 x 3/4" long UNC. Pretty standard size.

[ra.ra]

 

4 hours ago, Stimpy said:

....not sure if this is a standardized thing?

Yep, as DavidR has already noted, these are standardized dimensional prescriptions for machine screws. The first number (say 6 or 8 or 10....) represents the diameter of the screw thread; and the second number (24 or 32 in this case) represents the number of threads per inch. The third number is simply the length of the threaded portion of screw. While he has mentioned a 10-24 screw, I believe many smaller AR drivers use 8-32 screws and T-nuts. I am sure there are better sources for hardware, but even the Parts Express offerings list more than one size of hurricane nut. I think I would still use epoxy when installing hurricanes, and I would use a screw to slowly draw them tight to the cabinet rather than the hammer approach which is often mentioned.  

[DavidR]

Yes, ra-ra. There could be other sizes. The 10-24 was for the woofers.

MSC 10-24 screw

MSC is a good supply source

[JKent]

Some discussion of H-nuts and how to install them: https://forum.polkaudio.com/discussion/158916/question-why-hurricane-nuts-instead-of-tee-nuts

[newandold]

I know the temptation to walk away from Tnuts when the particle board strips or breaks away, but it’s important to remember that the  particle board itself is the REAL problem.

When the drill holes are made for the drivers, invariably one occasionally ends up where the board is weaker than in another location, so later on we end up with the problem. Carefully handled, the T nuts are just fine and I replace one that’s impossible with a nylon hollow wall anchor.

Bill

 

[DavidR]

Epoxy

[Markkb]

Here's another option, suggested by someone at AK, they have these in different shapes and thread sizes. You'd have to be able to screw them in, from inside the cabinet...hmm

 

https://www.pegasusautoracing.com/productselection.asp?Product=MS21059

 

mark

[JKent]

On 12/13/2018 at 9:44 AM, DavidR said:

MSC is a good supply source

Another good source for hardware items, specializing in stainless, is Albany County Fasteners. They even have the T-nuts in SS: https://www.albanycountyfasteners.com

[Guido57]

One might rebuild the ripped section of the baffle with something like Elmer's Damaged Wood Repair.  It's an epoxy product that once cured will be stronger than the original particle board and can be worked (sanded, drilled, etc.) like wood.  It has worked well for me on speaker baffles and more demanding applications.