Afixxing a Rail Button

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El Phantasmo

El Phantasmo

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Here's my minor dilemma. I forgot to place a nut inside of the body tube for a rail button. What's my best option? Just put a dab of epoxy on the screw threads and screw it on? It's on a LOC NORAD if that matters.
 
Best route is to run the screw into a centering ring, if you can find out. I'm not very good at that....

Your problem is easily solved... Drill a hole for the screw, thread the screw in, and verify the rail button is in the right spot. Remove the screw, and mix a small batch of epoxy. Lay the rocket on its side, with the rail button hole on the side. Squirt the epoxy into the hole, install the rail button, and roll the rocket so that the rail button is down. Let it sit like that for a few hours.

The epoxy will run down and collect around the threads, helping hold it in place.

-Kevin
 
That's what I figured I'd have to do. The hole is already there, I just forgot the the backing nut.

Thanks
 
I've managed to drill into the centering rings with some success... If I do a careful job of measuring, I use a push pin to poke through the side of the body tube... it's pretty easy to tell if you've hit the CR or not. You may end up with 1 or 2 pinholes in the airframe, but if they're close to the right spot, they can be covered by the rail button.

Of course, if you haven't already painted and polished the rocket, you could fill any tiny pinholes. But that would be smart.
 
I used Aeropoxy adhesive to attach a nut, then sculpted and aero fairing around it, with Aeropoxy Light. It's pretty solid.

Greg

P1000460S.jpg
 
Check Grainger or McMaster-Carr for a device called a well nut. It's essentially a nut inside a rubber sleeve. You drill an hole in the airframe, stuff this thing in, and when you tighten the screw it swells up on the back side of the hole holding everything in place. I used them to retrofit rail buttons to an older rocket with standard launch lugs when the appropriate sized rod was not available.
 
I had a small problem with well nuts, but found an easy solution...

When I tightened the rail button screw down into the well nut, the button sunk into the rubber of the well nut, which would interfere with putting the button onto the rail.

My solution was to to put a fender washer between the well nut and the rail button, which basically flattens the rubber out and prevents the button from getting sucked in.

Does anyone else have this problem, or am I doing something wrong? Maybe I'm overtightening the well nut? I'm using a 10-24 well nut with standard rail buttons, so maybe a smaller well nut would be better?
 
I also have needed to use a washer to have it mate properly on my retrofits.

slogfilet said:
I had a small problem with well nuts, but found an easy solution...

When I tightened the rail button screw down into the well nut, the button sunk into the rubber of the well nut, which would interfere with putting the button onto the rail.

My solution was to to put a fender washer between the well nut and the rail button, which basically flattens the rubber out and prevents the button from getting sucked in.

Does anyone else have this problem, or am I doing something wrong? Maybe I'm overtightening the well nut? I'm using a 10-24 well nut with standard rail buttons, so maybe a smaller well nut would be better?
Click to expand...
 
Well nuts are an excellent idea! I have a few relatively large ones on hand; hopefully, I can find ones small enough at my hardware store. McMaster-Carr is excellent but not price effective when purchases are only a few dollars, unless you can't get them elsewhere.

A LOC NORAD has only one centering ring at the tail, so the upper rail button has no centering ring for anchoring.
 
slogfilet said:
I had a small problem with well nuts, but found an easy solution...

When I tightened the rail button screw down into the well nut, the button sunk into the rubber of the well nut, which would interfere with putting the button onto the rail.

My solution was to to put a fender washer between the well nut and the rail button, which basically flattens the rubber out and prevents the button from getting sucked in.

Does anyone else have this problem, or am I doing something wrong? Maybe I'm overtightening the well nut? I'm using a 10-24 well nut with standard rail buttons, so maybe a smaller well nut would be better?
Click to expand...

I use 8-32 well nuts for my rail buttons and I don't have that problem.

Ace Hardware usually has them, some auto parts stores, marine supplies, and motorcycle parts stores may have them. Lowes might even have them.
 
El Phantasmo said:
A LOC NORAD has only one centering ring at the tail, so the upper rail button has no centering ring for anchoring.
Click to expand...

Just move the top rail button up where it will hit the bottom of the plastic reducer. Put a dab of epoxy on the threads and in the hole you predrill for the screw and it will hold just fine.

Jason
 

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