Reinforcing/Hardening cut threads in fiberglass?

[jahall4]

We often reinforce or harden cut threads in ply and other material, even cardboard sometimes, with glues like CA, but does anyone have a method of hardening threads in filament wound fiberglass that really accomplishes anything?

 

[Steve Shannon]

The best way would be to use a pem insert.


Steve Shannon

 

[jahall4]

The best way would be to use a pem insert.


Steve Shannon

Certainly and I usually do on #4-40 and larger, but on this occasion its for #2-56.

 

[cvanc]

I've done some 2-56 tapped holes in glass tubing and in my experience the threads held up just fine with no special treatment.

(On the other hand I grew quickly to not enjoy working with such tiny fasteners under field conditions and I eventually stopped using them altogether. I guess my eyes just aren't what they used to be LOL)

 

[jahall4]

I've done some 2-56 tapped holes in glass tubing and in my experience the threads held up just fine with no special treatment.

(On the other hand I grew quickly to not enjoy working with such tiny fasteners under field conditions and I eventually stopped using them altogether. I guess my eyes just aren't what they used to be LOL)

Yep, that's why I started using a magnifier.

...and I just found these and they are available in 2-56 (4-40 & 6-32 too): https://lumadyne.com/index.php/hard...-mating-nut-pre-treated-for-composite-bonding

 

[Steve Shannon]

Yep, that's why I started using a magnifier.

...and I just found these and they are available in 2-56 (4-40 & 6-32 too): https://lumadyne.com/index.php/hard...-mating-nut-pre-treated-for-composite-bonding

Nice! Pricey, but nice.


Steve Shannon

 

[Banzai88]

Yep, that's why I started using a magnifier.

...and I just found these and they are available in 2-56 (4-40 & 6-32 too): https://lumadyne.com/index.php/hard...-mating-nut-pre-treated-for-composite-bonding

Nice! Pricey, but nice.


Steve Shannon

Those are the same ones that Apogee sells. Their selling point is that they're treated to have a surface that bonds with epoxy. BUT, they're lacking the external teeth that bite into the material like a traditional PEM nut. They're also very tube wall thickness specific and meant to be used as a set (inner and outer washer).

For the money spent, traditional PEM nuts work better.

 

[jahall4]

Those are the same ones that Apogee sells. Their selling point is that they're treated to have a surface that bonds with epoxy. BUT, they're lacking the external teeth that bite into the material like a traditional PEM nut. They're also very tube wall thickness specific and meant to be used as a set (inner and outer washer).

For the money spent, traditional PEM nuts work better.

There are lots of PEM nuts/fasteners, got a link to some #2-56 that don't bite? Biting not desired for my FWF couplers. :wink:

 

[Banzai88]

There are lots of PEM nuts/fasteners, got a link to some #2-56 that don't bite? Biting not desired for my FWF couplers. :wink:

You want PEM nuts that don't have teeth? I have no idea. The ones that I use on all of my FWF parts are from McMaster and have teeth. They work perfectly. I roughen them up some, and the area of the tube, and then put a little JB weld around the perimeter. Never had one fail or fall out.

https://www.mcmaster.com/#captive-nuts/=17vs9rc

 

[jahall4]

You want PEM nuts that don't have teeth? I have no idea. The ones that I use on all of my FWF parts are from McMaster and have teeth. They work perfectly. I roughen them up some, and the area of the tube, and then put a little JB weld around the perimeter. Never had one fail or fall out.

https://www.mcmaster.com/#captive-nuts/=17vs9rc

Somthing like this: https://www.mcmaster.com/#95185a103/=17vsk11

They ought to work great! Particularly if you don't want insert on the outside. I was just on the phone w/Mcmaster they couldn't come up with these

 

[Banzai88]

Somthing like this: https://www.mcmaster.com/#95185a103/=17vsk11

They ought to work great! Particularly if you don't want insert on the outside. I was just on the phone w/Mcmaster they couldn't come up with these

Detail drawing of those shows that it has teeth on it. .166 mounting hole.

 

[jahall4]

Detail drawing of those shows that it has teeth on it. .166 mounting hole.

It wouldn't consider them teeth and any damage to the FWF is mitigated by drilling the receiving hole slightly over-sized.

 

[StanO]

Yep, that's why I started using a magnifier.

...and I just found these and they are available in 2-56 (4-40 & 6-32 too): https://lumadyne.com/index.php/hard...-mating-nut-pre-treated-for-composite-bonding

Nice find. thanks
StanO