mikenlapaz

This is a new hobby for me and when the need to make some uniform z-bends in 4-40 wire, I researched here ( and ground up a pair of perfectly good pliers turning them into almost junk and not a useful tool); went to my mentor and ask advise and was given his z-bend pliers with the assurance that they would work, (they did fine on 2-56 but with 4-40 and one bend results were not really what I wanted. Found several commerical units, vise held, that looked promising, on the internet, but I did not want to wait a month for them to arrive.
This is what I came up with and the results. Two small compression pins and a piece of oak and viola a hand-held consistant z-bend tool.

Now to make one for my mentor, so he can do 4-40!
Edit (Actually a little large piece of oak would allow perfect plane algnment or the bends. 2nd bend with the wire sliding on a flush surface.)

Rodney

IMHO Zbends should be restricted to park flyers or slow flying .40 size or smaller planes. Any Z bend joint is just begging for slop and flutter, if not initially, as soon as that oversized hole starts wearing. I suggest you go to either good clevises or ball joints if you value your plane.

CafeenMan

I really don't agree with this. I am extremely fussy about the hardware I put in my planes and I trust Z-bends over all other connectors. They and L-Bends are the only connectors that I've never seen fail.

You do not need to make the hole oversize. Most people just use brute force to work the Z-bend in which does distort the hole permanently.

First, I don't make Z-bends out of threaded rod. The bends flatten and widen which means the wire is no longer round. I only make Z-bend from 1/16" or smaller music wire and I would trust them on planes up to 2.0 size (assuming the wire was short enough not to flex).

The idea is to push the bend straight into the hole until it hits the first shoulder. Then SLOWLY rotate it in place. Nylon will stretch around the bend and then come back to shape if you do it this way. If you just jam it in, then yes, the nylon will get torn up.

The problem is technique, not the system itself.

- Paul

mikenlapaz

Rodney : My plan, at present, is to use thick CA on the Z connections once they are installed and adjusted to take any slop out of them. Let the glue function as a formed bearing surface for the wire to rotate in.
If slop develops give it another shot of CA.


CafeenMan : [] I'm a bit confused and inexperienced. I read 1/16" as about 2-56 thread material. I visualize a 2.0 size as larger than say a H9 UltraStik. What applications do you use the small wire z-bends?

My application is to connect to PVC large control horns with .085" thickness. A scrap of an electrical outlet box material is pictured. They are going on a Kraut's UltraSPADStick. http://www.spadtothebone.com/SPAD/ultraspadstick/

CafeenMan

I like to use them on servo arm and especially on throttles and nose gears. 2-56 threaded rod is about 5/64" and is soft steel. The reason I don't use it is because of what I said in my previous post - it distorts. It's not the size of the wire. I would use Z-bend in larger wire if I could bend it, but I've had problems with sizes music wire over 1/16" cracking when I try to Z-Bend it.

Another example. If I had a servo mounted in the aft end of a fuselage and could keep the pushrod to about 4" or less, I would have no reservations about using a Z-Bend on a larger airplane. But the bottom line is to always check the pushrod flex by putting some force on them. Check slop by wiggling the controls. If it's not right then fix it. If you don't trust something, don't use it.

It's no fun flying an airplane that you're stressed about losing because you don't trust something in it. If you don't trust Z-Bends then don't use them.

mikenlapaz

application: rons and flaps will have 5.25" of rod, not much flex in that distance. Might lash a bamboo skewer on the ron rods.

narpets

I quit using Z bends long ago as no matter what I do, mine devlop slop over time. I have been using U-Bends in their place, and have soem rather old planes taht get flow a lot and so far no slop has developed. As an added bonus they are VERY easy to make.

doctorgo

My Feedback: (5)

U-bends? U-betcha!

narpets

Gee finally someone else who likes U-bends