Finishing the Ferrule Installation Tn The Wires

The wires are formed, and the fittings and turnbuckles are in the loops.  Now I need to slide the ferrules tight to the loop and bend the tab over.  Unfortunately the ferrules fit very tight, even if the 2 pieces of wire are very straight.  I experimented with several clever ideas for how to seat the ferrule, well maybe not so clever.  I finally figured out a simple process for all this which seems to work well.

First off the wires are about 5 feet long and bend easily so I needed a stand tall enough to keep the end of the wire off the floor.  Hanging vertical seems the only safe position.

All this resulted in a stand I can clamp to my work bench.  The long piece of 2x4 has a slot sawn in it for the wire to dangle in, while pounding the wire down into the ferrule.

The base board allows it to be clamped to the workbench and the angled pieces, nailed in place, make it all rigid.

The end of the 2x4 is too soft to last long pounding on it so I added a piece of 1/8" x 1 1/2" steel angle.  I still have 84 ferrules to do in the fuselage when the wings are done.  The slot makes it easy to set the wire and ferrule in it.  The vertical leg of the angle traps the ferrule with the wire in the slot.

The ferrule is trapped on a solid surface and the free end does not touch the floor.

Before putting the clips and turnbuckles on the wire ends all the Loops were painted.  I did them now so the clips and turnbuckles don't shadow the wire and so I'm only painting the wire.  I'll paint the ferrules and main part of the wires after finishing the ferrules.

The ends with the wire clips cause a little problem.  There is no way to pound directly on the end of the loop because the clip is in the way.  I suppose I could pound on the clip, too tacky.

I made a pounding block from a piece of 1" square oak with a notch to fit over the clip and wide enough to just clear the eyelet.

You just pound it down until the ferrule is firmly seated against the loop.

With the turnbuckle end you just use a plastic mallet and pound directly on the loop.  So easy.

The next thing is to bend the free end around the ferrule to lock it in place, without bending or nicking the main wire. 

I clamp it in the vise tipped like this so it won't rotate up when I bend the free end.

I start with my modified Vise Grip pliers about 1/16" from the end and start the bend up just enough to move the pliers in closer.  I want the bend tight to the ferrule.

With the pliers re-positioned I bend the end up to about 90 degrees, as far as I can until the pliers touch the ferrule.

Reposition the pliers, rotated 180 degrees, then bend to the ferrule.

To close the bend a little further I squeeze it in the vise.

It leaves a fairly tight bend which will give 85% to 90% of the strength of the wire.  I use the loop shaped like an AN100 thimble to minimize the stress at the bends.  A more round shaped loop will break at an even lower load.

The WACO Factory used tinned wire and soldered the ferrule after making the locking bend.  I can't get tinned wire, which has Hydrogen Embittlement problems that can cause the wire to fail.  To tin the wire you have to use very aggressive flux containing hyrdo-whichever acid.  The hydrogen gets trapped under the tinning, eventually penetrating the steel matrix preventing it from flexing.  It shatters instead.

NACA Report No. 3 says that soldering adds no strength to the joint.  They recommend wrapping the free end with wire to lock it in place, adding a little more strength to the joint.

To do this I clamp my modified pliers in the vice and use them to hold the ferrule and keep the free end tight while wrapping with safety wire.

I use 3 turns with 0.041" stainless safety wire.  Twist it tight.  Fold the cut end under for safety.  I am so tired of bleeding on everything.  Then release it from the pliers.  It looks like the picture in Report No. 3 only I use 3 turns they used 1. 

The safety wire sets nicely in the grooves of the ferrule.

 Solder may not add strength but it seals the ferrule joint and protects it from rusting.  I wanted to create the same protection for all my hard work.

I was planning to fill them with epoxy but it is too viscus and will not flow into the voids without a vacuum to pull it in, much to much work.  Instead I seal the outward end with a dab of 5 minute epoxy.  I'm creating a little cup with the epoxy making the bottom and the coils of the ferrule making the sides.

I like to control the mix of small quantities of epoxy with 2 equal size circles for a visual guide.

 I'm using a bamboo skewer to mix and apply the epoxy.  The point is nice for applying and you just cut off the used end and resharpen it for each new batch.

I let this seal, on each ferrule, cure for 5 minutes hanging on a peg seal end up.

After the seal cures I fill a small syringe with Oil based spar-polyurethane varnish to seal the inside of the ferrule and wires.  I think I found these for giving babies small amounts of medicine.  They say monojet on the side and hold 1.0 ml.

I slowly drip in 0.3 ml of varnish.  Then I hang them to dry for a day.  I wrap the clip or turnbuckle with foil in case a little drips out.

When the varnish dries you can see it has just penetrated between each of the coils.  Everything inside should out last me and the grandkids anyway.

The ferrules and wire get a coat of primer and 2 coats of metallic Rust-Oleum Satin Nickle.

Yea!!  We can finally build a wing.

Forming The Loop Ends of The Drag Wires

Before we start I added some notes to the end of the wire Straightening post.

I need to bend this hair pin looking bend on both ends of each drag wire.  One end gets a turnbuckle and the other gets a Wire Clip (attachment fitting).  The free end gets squeezed closed, a ferrule slipped on tight, and the end of the wire bent over to lock it together.

We're doing this on each end of a piece of 1/8" piano wire about 5 feet long.

I did something similar for wire wrapped cable bracing so I thought I'd build on that idea rather than build the more complicated WWI wire bender, for which I have drawings.

The bends are the same on the 1/8" 1x19 cable.  The cable is easier to bend, but it springs back more .  When finished they both have the same shape.

I bent the cable with battery terminals.  They have the perfect shape for forming the cable bends.  They also keep the cable trapped in the groove while bending.

They're made of brass which is not hard enough for bending our piano wire so I can't just use this bender

First I made some posts to bend the wire around.  They're made from a 3/16" AN bolt, 2 washers, and a short piece (5/32") of 5/16" x 0.058" wall thickness 4130 tubing.

I ground the end of the tube square, cut off a piece slightly too long, then ground the cut end square and to length.  To hold them while grinding I used a longer piece of the same tubing with a piece of 3/16" rod inside.  I left the end sticking out 1/8", put the short piece on it, and ground it down very gently while rolling it to keep it square.  It works real good.  Being careful you can control the length to 0.0005".

Four bushings.

I didn't have a completely clear idea where I was going when I started, so I built this as I did each step in the first piece I bent.  Surprisingly it works very well.

I use the Dremel tool to cut off the wire.  I like the new quick change wheels much better than the old ones.

I blunted the ends of the wire so it will slide into the ferrules easier after all the bending.

An allowance of 5 1/2" from my bend reference line gets just the length I want to bend over the ferrule at the end. I mark it with a Sharpie.  We use this mark for the first 2 bends.  The mark is not at the bend which is hidden under the lever.

The base of the bending fixture is a piece of 3" x 2" x 3/16" angle iron.  For this First bend I'm using one of the posts at the pivot of the arm.  I have a piece of 1/8" steel to back up the bend on both sides of the post.  It helps get a sharper bend.  Without it the wire on both sides of the post tend to be curved a little and here I want them both straight.

You can see from the side how I had to use washers to get clearance for the bolt heads.

Below is the backing bar on the bottom of the lever.

The first bend is made by eye, over bending slightly, so the wire springs back to the bend line.  The lever is rotated anti-clockwise to make the bend.

The finished bend is 15 degrees.

For the next loop bends there are 3 of the bending posts.  One is at the pivot of the lever.  The other 2 are 5/8" away, one attached to the bottom of the lever and the other on the base.  The reference line gets the wire in the same position relative to the bend post as in the first bend.

I found I need to use a pair of pliers to grip the wire to keep it from moving.  The pliers have been modified so they won't scratch the wire.  More on them at the end of this post.  They're really part of making that locking bend around the ferrule.  The stack of washers keep the pliers from moving.

The lever is rotated Clockwise until the wires touch.  This leave the 2 sides of the loop parallel.

With a 5 foot piece of wire I had to do this on my deck outside the attic workshop.  The end of the wire is actually resting on the far railing.  Life works out some times.

The wire goes back into the fixture so the free end goes from the left of the fixed post, past the right side of the pivot post, then to the left of the post under the lever.  The wedge of scrap spruce keeps the loop tight to the fixed post.

The lever is rotated anti-clockwise, over-bending slightly, so the wire springs back to the red line.  The finished bend on this side is also 15 degrees.

The 2 sides are still parallel but it's looking more like our hairpin bend.

Back into the fixture like it was for the 2nd bend to add a few more degrees of bend to the loop.  The idea is that when the loop is closed, when the ferrule is installed, the free end is snug to and parallel with the main wire.  That's why I didn't want any bending of the main wire when I formed the first bend.

We have our finished hairpin bend.

That takes care of the loop at the first end.  The second end is almost the same process.

To make the second loop I've added a 6 foot piece of 2x4.  I pounded the back of the fixture onto the board, with a soft mallet, so it would mark where I needed 1/2" holes for the bolts and nuts.  The fixture is screwed to the board.

A c-clamp holds the board to the railing of the deck while doing the bending.

It turns out that one of the few accurate things on the old drawings is the length of these wires.  The board allows a place for stops to control the length of each cable.  For stops I used 16d finishing nails cut 2" long and re-pointed on the belt sander.  I positioned them so they can all be permanently installed and each wire clears.  The first bend is offset 1 inch to the right of the 2nd bend so there are 2 sets of stops, offset by 1 inch.  There are 2 wires which are shorter then 2 other wires by 1/8" and by 1/4".  Rather than clutter the fixture with more pins I have notes to open the turnbuckle 1/8" and 1/4" when making those wires.  Ok, I know that's not fool proof so let's hope I can focus long enough not to screw it up.

The first step for the second end is to loosely attach a turn buckle,  slide on 2 ferrules, then start one ferrule onto the free end to hold it shut.  I have a reason for not finishing this, we'll get to it in a later posting.

I had to modify a pair of pliers to squeeze the wire without scratching it.

I filed a pocket in each side with a 5/32" chainsaw file, then rounded the corner with it.  We don't want these wires cracking from some scratch.

The pocket holds the wires together to slide the ferrule on.  You can't push them all the way on like this so I'll need another tool for that, later.

I adjust the turnbuckle to have the threads just at the ends of the barrel.  The wire is positioned in the fixture as if to make the first bend, with the turnbuckle on the appropriate pin.

The reference mark is made on the wire.  The wire is removed and positioned so the mark is on the line. The wire is then marked to cut off the excess, leaving 5 1/2" form the mark.

The end is again blunted.  The second end of the wire is now bent as before.  The clamping pliers are not needed because the turnbuckle end is held by the pin.  After the second bend is made you need to loosen the turnbuckle to get the wire out for the 3rd bend.

With the both ends formed, the wire clips were loosely installed and the wires bolted into position to verify the length.  The length was a fit perfect, well done WACO draftsman.

All the wires are formed for both lower wings.

On to the upper wing wires.

The visegrip pliers were modified to be able to grip the free end sticking out of the ferrule and bend it most of the way around.

I used the Dremel cut off disk to grind a more round hole in the tip of the pliers.

Then I filed the corners round to prevent scratches.

The tip of the pliers was then ground off on the belt sander.  Keep in mind I'm trying to grasp a wire end setting very tightly against the main wire.  I can always grind it down more if needed.