I know this has been covered, but....Rail Button installation using well nuts

Hi guys. So I was thinking of using some well nuts to install 1515 rail buttons on to a couple larger projects I am building. 6" diameter, 8-10 feet tall, flying on M and N motors. They are scratch build. Using Hawk Mountain tubing. I know the 1515 rail buttons use 1/4" screws. I found a PDF online with all the technical info regarding well nuts manufactured by Emhart, they must be a larger manufacturer, they were first to come up in a google search.

Anyways, the tensile strength listed is anywhere from 140 - 445 pounds depending on exactly what model of well nut purchased. I would imagine this would be plenty of tensile strength but would like to know what the largest rocket you have used well nuts to secure the rail buttons. I know there are several other ways to install rail buttons but I like the idea of well nuts because they are easy to use, and of course would be easy to change.

Let me know any thoughts you have and provide any feedback which would be helpful.

Thanks
Steve

I used them on my 7.5 diam Gone Bananas project weight 58lbs 12ft and my 6in 14ft 54lb project. Both have flown on N'motors with no issues.

I used the size requiring 3/8 holes for the well nuts. I did use stainless screws however, purchased aftermarket from a hardware store

The 6in Tiger Terror rocket is all Hawk Mountain tubing. It has withstood 14 M flights and 2 N flights so far. It weighed in at 68lbs with the N in it.

You should have NO problem with them.

By the way Ken Allen of Performance Hobbies carries them now. I THINK I paid 5.00 for the 1515 set complete with well nut and machine screw. I know it was no more than 10

Another good source of well nuts is McMaster-Carr. Of course you have to buy a box. For the 1010 size ones I use a box of 25 was about $14.

If you just need a couple ; Ken is a good source.


Al

You can also buy them through Amazon & their vendor network. Another option would be to; drill & tap the Hawk tubing without using them...


JD

I would not suggest tapping the fiberglass airframe as it is only 0.075" thick. This represents only 1 1/2 threads of the 1/4-20 thread and the recommended rule of thumb is that you want 5 good threads to get maximum strength out of the screw.

Attached is the link to the page of the https://www.mcmaster.com catalog that list well nuts and other applicable fasteners.

https://www.mcmaster.com/pdf/116/3270.pdf

You may find that the non-rubber rivet nuts are less expensive and lighter, however the rubber well nute (rivet nuts) are removable.

Bob