Nylon fasteners

[RodneyPierce]

Where is it OK and not OK to use nylon fasteners? How about to hold the sponsons to the boom tubes? I had to replace my booms last weekend after a crash, and was thinking about tapping the 6061 pins I have in my sponsons 4-40 and using short 3/8 long 4-40 nylon screws to hold it all together. Will this be strong enough? I tried it on one side last night, and it seems rather strong just pulling on it.

Thanks in advance!!!

 

[Brian Sorgente]

I wouldn't recommend it on the booms. The weight savings isn't worth the risk. I've bent stainless screws after a good flip and also egged out the holes in the carbon fiber booms where the screw goes through them. I doubt a nylon 4-40 would hold up for very long, especially on the turn fin side.

Just think about what happens if one screw gets sheared, it goes from pulling on the boom in the corner to acting as a lever on the opposite one which could break it pretty easily.

Tapping the booms on the other hand works great, I've been doing this for years and there is NO slop in my sponsons. I get everything clamped the way I want, match drill and tap the booms for 4-40. Screw the 4-40 in until its good and tight then put a nut on the other end and tighten it like a jam nut. Rock solid.

I think you could probably get away using nylon screws on throttle/ 3rd channel servos, pipe mounts, cowl mounts, needle base mounts... etc. Just make sure to use an adequate diameter, I use 1/4-20 nylon screws to hold in the zenoah in my gas rigger and they seem to hold up ok for the most part.

Brian

 

[steve wood]

Where is it OK and not OK to use nylon fasteners? How about to hold the sponsons to the boom tubes? I had to replace my booms last weekend after a crash, and was thinking about tapping the 6061 pins I have in my sponsons 4-40 and using short 3/8 long 4-40 nylon screws to hold it all together. Will this be strong enough? I tried it on one side last night, and it seems rather strong just pulling on it.

Thanks in advance!!!

we ripped the aluminum stub clear out of the first g2 turn fin side.i'm sure it would shear the nylon bolts in the corner

 

[anthony_marquart]

I think ti would be ok, except for the rear boom on the TF side.. That would probably shear off.

 

[RodneyPierce]

Ill stick to standard steel 4-40 fasteners then.  I also use solid 6061 pins in my sponsons, and on the TF pin, drill and tap the end for a 6-32 fastener, so the force is applied to the entire sheeting instead of just pulling on that pin.

 

[Ron Zaker Jr]

Ill stick to standard steel 4-40 fasteners then. I also use solid 6061 pins in my sponsons, and on the TF pin, drill and tap the end for a 6-32 fastener, so the force is applied to the entire sheeting instead of just pulling on that pin.

aluminum and or titanium

 

[dwilfong]

Carbon boom tubes and solid carbon rods in the sponsons with 4-40ss screws hold the sponsons on my SGX90.

It has bin bounced off a fence and dives in the corners at very high speed full rudder with a very big titanium turn fin.

Still in one piece never change any of the parts.

David