Aiden88

My Feedback: (5)

I'm building my 4 Star 40 and I ran into a weird situation. I'm at the part where I'm working with the servo/control linkages. The instructions say to cut two 2-56 steel rods and then thread the threaded end intothe inner (smaller) nylon tubes that runthe length of the fuse inside the outer (larger) nylon tube backto the exit points. Theinner tube fits fine intothe outer tube and slides easily back and forth but the threads of the rods slide easily into the smaller tube. So, there is no way to thread the rods intothe tube because the inside diameteris toolarge and the threads won't grip.

Any suggestionsas to how I can work around this? I'm afraid to glue the rods into the tubes in case Ineed to make adjustments later but Idon't see any other way.

big max 1935

My Feedback: (9)

Get a couple of 4-40 threaded rods . They should work & larger won't hurt. Max H.

Aiden88

My Feedback: (5)

Thought about that but was hoping to work with what I had. Don't have any spare 4-40 rods... Grrr, looks like another tower order and of course I can't just buy rods.

ARUP

I ran wooden dowel pushrods in lieu of the nyrod setup. Got any spare dowel rods? A local hardware store should have them if you don't and they're cheap!

Gray Beard

My Feedback: (-1)

You may want to pick up the phone and just call SIG.

airbusdrvr

I would first check to see that your 2-56 rod really is 2-56. Second option, buy a good set of these, http://www3.towerhobbies.com/cgi-bin...&I=LXFU90&P=ML

Aiden88

My Feedback: (5)

I called Sig but their techs don't work on Fridays so was told to call back on Monday. I wish I could take every Friday off.

If I ordered from Tower this morning I'd have my parts by Tuesday or Wednesday,so will just go that route. Too bad I already ran and glued in the larger nylon tubes; the Sullivan golden-rods look good. They are cheap enough that I may just order them anyways along with some 4-40 rods. Of course now by servo arm connectors probably won't work with 4-40 rods.

I hate issues like this but on the bright side, this is usually when I learn about new techniques and products.

big max 1935

My Feedback: (9)

They make long rods threaded on on end .I have used them & I like them best of all . I put a "Z" bend on the servo & a clevis at the surface . good luck , Max

Lnewqban

You could try some bicycle wheel's spokes.
They may have the extra thread external diameter that you need.

Another option is to stretch the ends of the inner plastic rod with a flame.
By doing that, the interior diameter will be reduced as much as you need.

Best luck

Aiden88

My Feedback: (5)

I put a lighter flame to the tube and once it started to soften I put the tube under cold water. I then was able to thread the rod into the melted tube. Hopefully I can do the tail-feather end without burning my airframe to bits.

airbusdrvr

I'm not suggesting that this idea will not work and work fine. However, this technique has the potential to fail in flight. Then when the airplane dosen't pull out of that loop, the first thought will be I lost "radio" control of the plane. It must have been my ________(Spektrum, Futaba, Hitect, etc.) transmitter or receiver. And so starts another radio failure thread.

Villa

I fully agree that heating and stretching the tube is way too risky. You do not know how you may be changing the chemistry. I would look for a safer alternative.

carrellh

When I assembled my 4*60 ARF, several people said I should replace the nylon pushrods because they expand and contract with temperature changes. I found 4-40 solid wires fit very well in the stock outer sleeves so that's what I used for elevator and rudder.

airbusdrvr

I am not familiar with the stock that is supplied with the SIG Four Star 40. Sullivan Golden Rods are very reliable and should not be bothered by temperture ranges to which the model will be subjected. 4-40 wires are great. If I were to elect to do what Aiden88 did(heat and recool), I would really give the finished wire/inner rod a good pull test. Something in excess of what the servos would be able to exert. I have used quick connectors and such on throttle and nose wheel steering applications. I have played with other connections on non-flight critical areas. But the elevator is the one place I will only use z-bends or good quality clevis connections. Aileron failures can often be over come by the rudder and vice versa. But only luck will overcome an inflight elevator failure.

Aiden88

My Feedback: (5)

I gave them a pretty intense stress test trying to pull the rods out but couldn't get them to budge. I had to use pliers and a vice grips to even get the rod to thread inside the tube. When I water cooled the tube it hardened like a rock. With that said, I'm not going to risk losing my model because I was too lazy to take a trip to the LHS for a $2.00 fix. I'm not one to ignore good advice either, Looking like Tuesday will be a hobby shop run to find a more reliable solution. Thanks guys.

RCVFR

My Feedback: (7)

Are you sure your rods are 2-56 and not 2mm? Did they come with the kit or did you have them on hand? I have never encountered 2-56 rod that would not tightly thread into nyrod inner tubes. You may have a non nyrod product, but it would seem a good idea to verify dimentions of what you have. Good luck.

Aiden88

My Feedback: (5)

The 4 Star kit comes with six 10" 2-56 rods. They are the ones I'm using and they thread into clevis' that come with the kit just fine. All of the hardware is from the kit. However, when those rods didn't work I tried using other rods off my other .40 size models but the threads just slide in and out of the tubes. It is really weird but appears that the outer diameter of the tube is right but the inner diameter is too large.

The 4 Star Kit is pretty basic and their isn't a lot of hardware. I've triple checked everything and pretty much have concluded that I've just got unlucky with these tubes. Fortunately it's an easy fix.

Lnewqban

Between the #2-56 and the #4-40 US threads, there is the #3-48, which takes a #47 drill bit before tapping.

Drill bit for 2-56 is #50 and for 4-40 it is a #43.

Since you will not use the heated and stretched tube-rod, it would be good to do some destructive test on it.

Aiden88

My Feedback: (5)

I found out from a guy in a 4 star thread where a hegot his kit and then a day later got a package of nylon tubes from Sig explaining they had a batch of 4 Star kits with the wrong tubes. Feeling a bit vindicated...

I finally got around to calling Sig back and he confirmed the batch of bad tubes... Replacement tubes are on the way.