Hardware (fastener) question

[wa3drc]

I blew out the foam on one of my L166's today. JBL serviced these a long while back for the same issue.

I tried to get the woofer out and the screws just started spinning. I eventually got them out by drilling thru the screws. In the end I only found 3 of the 4 fasteners that hold in the screws.

While I have seen these many times before, I don't know what they are called. Can someone enlighten me and where can they be found?

thanks,
Ed

[BMWCCA]

While I have seen these many times before, I don't know what they are called. Can someone enlighten me and where can they be found?

Probably T-nuts and look at any good hardware store. Previous repair might have stripped them.

[Horn Fanatic]

I blew out the foam on one of my L166's today. JBL serviced these a long while back for the same issue.

I tried to get the woofer out and the screws just started spinning. I eventually got them out by drilling thru the screws. In the end I only found 3 of the 4 fasteners that hold in the screws.

While I have seen these many times before, I don't know what they are called. Can someone enlighten me and where can they be found?

thanks,
Ed

BMWCCA is correct, the fasteners are T-nuts, to be exact, 10-32. Your problem may have occurred due to a cross threaded screw, which would have caused the T-nut to spin out, usually tearing up the wood in the process and possibly breaking off or bending one or more of the prongs. Trying to bend those prongs back usually results in breaking them off.

You may want to find the type JBL used, as the O.D. is reduced compared to the style found at any hardware store. The problem with that type, which is 3/4" in diameter, is that only two of the prongs will find a home in the wood because the mounting holes are very close to the cut-out, and those prongs typically are shorter then the type JBL uses.

Personally, I hate T-nuts. I think the person who invented them was a Sadist.

Good luck, H.F.

[wa3drc]

BMWCCA/H.F.

thanks for the information. I now know what those fasteners are called after seeing them for the past 40+ years!

I am going to ACE hardware to see if they may have them. If that fails, I do see that McMaster-Carr has them in quantities of 100. p/n 90975A023 looks right to me. I'll have 10 lifetime supplies if I go that route.

And yes, it looks like the little prongs rolled over and they were spinning around. It looks like whomever repaired them may have used a little loctite when they were reassembled.

thanks,
Ed

[Don C]

The trouble is that sometimes it is difficult to remove the screws, and it is natural to respond by pushing harder against the screwdriver wile turning the screws to prevent the tip from slipping. That pushes the t-nut back out of the wood and then it turns with the screw. It's not a good design for a cabinet that needs to be serviced. Sometimes you have to knock the rear connection panel into the cabinet and work from the back.

[SEAWOLF97]

I have had some experience with this problem. When the screws started to spin , but one backed out OK ,
the solution was obvious.

Wedged a screwdriver blade between basket and plinth near the spinner, pulling T-nut up and stopping the spinning. Or you can just lift the side of basket a bit where the removed one was. Mine had rotted foam so I could get a finger between the cone and frame to pull up.

Being cheap, I reused the nuts by hot gluing them in place before reusing. worked perfectly. ;)

[wa3drc]

thanks for the suggestions.

I destroyes a couple of the screws by drilling them out. I could not find fillister head screws at the hardware store so I just ordered some from McMaster-Carr.

The screws were p/n 91794A833
The Tee Nuts were p/n 90975A015

If anyone needs any, it looks like I'll have lots of extras...

Ed