<div>I see that the size of the clevis is denoted by two numbers eg. 2-56. I just want to know what does this numbermean. Sorry if the question is too dumb. I am new to making/flying RC planes.</div><div></div><div>Thanks</div><div>Sunit</div>

2-56, 4-40, 0-80, etc, etc refer to the thread and pitch of the screw size. It really does not relate to the size of the turnbuckle other than the smaller the thread and pitch, the smaller the length of the item.
The same is true of push rods and linkages, the larger the thread and pitch the stronger (or larger dia/gauge) the item is.
Make sense?

Thanks now it does make sense to me.<div>
</div><div>Sunit</div>

To expand a little:

A 1/4-20 screw has a diameter of 1/4" and 20 threads per inch. Most diameters have two thread sizes: Course and Fine (aka National Course - NC, or National Fine - NF)

So the two standard sizes for a 1/4" bolt are 1/4-20 (NC) and 1/4-28 (NF). There are also a few non-standard sizes but you rarely run into those.

As for numbers like "2-56" the "2" is a wire gauge size instead of a fraction

I believe you are confusing screw sizing with clevis descriptions. A clevis is usually described by diameter and length. Then of course the hole location. After all, a clevis is just a pin with a hole in it.

http://www.thread-rite.com/bee_leitzke/clevis_pins.htm
https://www.jamestowndistributors.co...me=Clevis+Pins

Hello sunipal,

I am illutrating what we usually refer to as clevis.

Some are threaded to accommodate threaded rods and allow for linkage length adjustment.
Some have no threads and are intended for soldering.

The two, one for rudder and one for elevaors are screwed in at the end of the control linkages.
One under the stabilizer allow for adjusting tension on the flying wire.


Zor

Wrong. A clevis PIN is a pin with a hole in it. Said pin gets installed through a clevis, to create a hinge type joint.
http://pneumatics-en.timmer-pneumati...lkoepfe-4.html

http://www.greatplanes.com/accys/gpmq3710.html

http://en.wikipedia.org/wiki/Clevis_fastener