Cable Splicing Clamp

 To form the looped end on the control cables using a 5 or 7 tuck splice method, or on bracing cables using the solder wrap method, the cable end must be held firmly while doing the work.  To hold the cable end you need a Cable Splicing Clamp.  The clamp is held in a vise while the other end of the cable is pulled snug during the splicing operations.  The clamp at right is from a 1930s Nicholas-Beazley catalog K.  The tab on the right is clamped in the vise and the wing nut on it is tightened to keep the clamp from rotating.  The wing nut at the top is used to move the center slider to clamp the cable securely in the curved jaws.  Back then a gallon of clear dope sold for $1.85.

 This picture from "Aviation Mechanics Made Easy" Vol. 4 pg. 526 (c1942) shows a clamp in use  on a control cable.  It also shows the other tools needed to form the splice, a marlin spike, rawhide mallet, and wire cutters.  You also need a hardwood block to pound against when tightening up the tucks.

 This clamp is from a 1944 Supply Division catalog pg. 75.  That same gallon of Berryloid dope was then $2.65 although a new Sensenich prop. for a J-3 was only $35.

 The one I've decided to use as a model to make my own is one I borrowed from Rich Wilbur who is restoring 2 WACO NINEs.  He made this one in A&P School so it seemed like something I should be able to copy.  I've had this for a year but couldn't find a piece of 1" steel to make the holding block on the vise end.  While making some tools for the Cessna 140 project I realized this block could be made from 1/2" x 1" mild steel like the clamp base piece.  All I need to do is screw 2 pieces together to make a 1" block.  In the end this is probably a better idea since it solves the problem of how to install the bushing which holds the block and clamp base together.

The 2 block halves were cut 1-1/2" long, ground smooth on one side, and squared up on the ends.  The Base piece is also cut from 1/2" x 1" mild steel 3" long.  The Jaw piece at the end is the same size but cut from 1/4" thick mild steel.  The pivot bolt is 3/8" - 24 UNF x 3" long.  The 2 Slider bolts are 1/4"-28 UNF with a grip length of 2-5/8".  The threads need to bottom out in the Jaw plate.  The ends get ground off smooth and staked in place.

The first part is the Knob for tightening the clamp to hold the cable.  It's a round disc of steel 1/4" thick, 1" in diameter, with a 3/8" - 24 UNF threaded hole for the bolt, and knurled on the edge for a better grip.  I started by drilling and tapping the hole in the end of a piece of 1/4" x 1" mild steel bar stock from Tractor Supply.  It's easier to drill and tap the bar than the finished disk.

A 3/8" hole was drilled in a piece of oak to use as a pivot to grind a nice round end on the bar.  The 1" end was then cut off the bar.  By making 2 45 degree cuts and then a square cut across the bar the piece is close to the desired finished (round) shape.

By using the same process but with the board clamped in place and moved closer to the belt in small increments the knob was turned to a nice round shape.  I have no way to knurl the knob so instead I used the band saw to cut into the edge of the knob about 1/32'' deep. Cuts were made dividing the edge into quarters, then eighths, and then 16ths.  It makes a nice grip surface.  The top and bottom edges were filed to soften the corners.

After using the Splicing Clamp to make about 10 cables, for my Fly Baby, I decided I needed to stop and make a larger, easier to grip, tightening wheel.  I originally made the wheel from the same 1/4" x 1" bar stock used for some of the parts.  It seemed clever and would work fine with flexible cable.  With the non-flexible 1x19 cable it was just too hard to get the cable tightened against the thimble.  You could do it but it took a lot of wiggling the cable while turning the wheel.

I decided I needed a wheel closer to 2" in diameter with nice big knurls for a good grip.  I also wanted to keep it 1/4" thick to have a reasonable number of threads.  If it wears out I may need to make one from 3/8" thick steel.

 The only piece of 1/4" steel I had was on some tools for making wire ferrules for the WACO internal bracing wires.  I decided it would be fine with a 2" hole in the base since I just clamp the base to my work bench.

I located a pilot hole for the 2" hole saw then used the saw to draw a centerline to layout a pattern of holes for the knurls.  It certainly took the guesswork out of where the center of the holes should be.

 I center punched a pattern of 12 holes, pilot drilled them with a 3/16" drill and finished them with a 5/16" drill.

 To round the edges of the holes, it makes more comfortable knurls, I countersunk the holes with a 1/2" center drill, steeper flutes.  Then I lightly countersunk then with a 1/2" twist drill.  It really makes a nicely rounded edge to the holes.

 Back to the 2" hole saw to cut out the wheel. I cut half way from each side and when it got close just pounded it out with a light hammer blow.  I didn't want to risk this 1/4" slug flying around.

It's looking like a thumb wheel.

 I cleaned up the outside radius with the belt sander and the chamfered the edge at 2 angles, sort of like with the hole edges.

 The remaining burs were cleaned up with the small sanding drum on the Dremel tool.  It needs to feel good in your hand and no sharp edges.

 The hole was tapped with a 3/8" fine thread to spin on the center bolt.

I had a little trouble getting the 3 bolts apart since I had put Loctite on the threads and cut off the head of the 3/8" both after tightening it in the clamping bar.  A little heat took care of the Loctite.  I greased the threads and the pivot with Molykote to keep the friction low.

A much nicer wheel.

Elevators Tack Welded

 The elevators are tack welded.  The finish welding will be done after the stabilizer is tacked together.  There are some fittings, which hold wooden blocks for attaching fabric around the hinges, that still need to be added.  I'd rather wait until I have the hinge attachments are on the stabilizer before before welding these fittings on the elevators.

Before I started welding these I took some time to review what information I could find on welding to see if there was something I should know.  The things I found that I are useful are:

There is an online engineering course "Fundamentals of Gas Cutting & Welding" D06-002 for which you can download the course materials (pdf).  It has some excellent explanations of the oxy-acetylene chemical reaction and other bits not covered in more how-to articles.

EAA Welding video  While your there also get the EAA Welding Manual.  It's mostly a reprint of the 1950 Navy Training Course NAVPERS 10322-A "Aircraft Welding", with some other interesting articles. My copy is almost as old as my copy of 10322-A.

Next is a great article by Budd Davisson "ZEN and the Art of the Weld Puddle" from EAA Experimenter, October 1993

The next is a series of 10 articles by Budd Davisson which started with the August 1987 issue of EAA Experimenter titled "Aircraft Welding and Steel Tube Fabrication". The last article was in the June 1988 issue.  Reprints of articles can usually be gotten from EAA.

Bob Whittier had a good article on heat treating welds titled "the Welding's Done! Now What?" It was in the July 1999 issue of EAA Experimenter.

I have more when we get to gas welding aluminum.

Control Horn Assemblies

Now that I'm back working on the planes I need to get the tail surfaces welded up.  I've had the elevator setting in the jig for 2 years.  It's time to move on.  I also need to weld up the wing fittings.  Getting the tail surfaces all welded should get my skills back to a level I'd be comfortable welding them.  The first task was to weld the control horns together.  The small vicegrips from Lowe's worked great to hold the shells together.  I should have put bolts in the holes on the tabs.  I ruined 2 clecos. 



I also found I left to much of an edge to weld nicely.  All the literature says to leave about 1 material thickness.  I left about 1/16", 2 thicknesses, way to much.  At times it would melt around the edge leaving a blobby look.  I also found that that the tab ends were easier to weld with the center layer, of the 3 layers of metal, sticking out about 0.010".  The weld puddle is easier to form because you can get more heat into the middle piece.


The fixture I used for fitting the tube to the horn is used to weld the horn to the tube.  One thing I learned is don't form the end of the tube to fit the training edge tube until this assembly is welded.  Things move a little and you want the horn square to the spar tube.

I now have 3 assemblies welded, 2 for the elevators and one for the rudder if I can't repair the existing rudder.

False Nose Ribs (P/N 362) For Rich Wilbur

Rich visited and we made him up a set of false nose ribs for his project. This brought up the issue of whether I would make part number 362 ribs for other Waco Nine or Ten/Straight Wing projects.  The answer is yes.  I would be happy to work with any owners to produce the parts as allowed under CFR 21.303 (b) (2) and FAA AC 20-62D.  With planes like these about the only hope we have to Keep 'em Flying is Owner/Operator Produced Parts.  The current cost for me to make these parts is $5.00 each.

Wing Details

 I haven't gotten anything done in months, but I did learn more about the wing construction. In June, on the way to the National Waco Club fly-in, I stopped in Zanesville, Ohio. Rich Wilbur purchased one of the WACO NINE projects owned by Tony and John Morozowsky. I had offered to help load the plane in Rich's trailer so I could meet him there to take pictures of whatever I could. Rich had plenty of help with him to load the trailer so I got a couple of hours to look at the wings.


The picture at the right shows something I did not pick up in the drawings. The wing walk seems a little narrow.  To fix this they widened the braces and extended the plywood for the walk about 3/4" past the rib.  It's not much but it has to help.


 The trailing edge on the wings is done with a hard wire like in WWI.  The drawings show nothing about how it was attached at the tip or the wing walk.  They use a strip of copper at the end of each rib.  The wire is soldered to the strip and it is nailed to the rib.  They did the same at the last rib and then ran the wire in a groove in the tip bow for about 4 inches.  The end of the wire then goes through a hole in the bow and gets bent back along the inside of the bow to lock it.  It's simple and it looks like it works fine.

 
 At the wing walk they used a piece of the steel aileron trailing edge material to solder the wire to and then soldered it to cooper strips for nailing it to the ribs.

Because the spars on the NINE are routed to reduce weight it was not clear how the ribs were attached. On the TEN the spars are solid spruce and the ribs are glued and nailed to the spars with 8 nails.  Two nails go through each cap strip into the top and bottom of the spar.  Two nails each then go through the vertical members of the ribs next to the spar.  The only area for those nails is in the routed area of the spar on the NINE.  Nothing is shown on the drawings about any of this.  From the wings it was obvious.  They used the same attachment as on the TEN with the addition of a piece of cap strip glued and nailed in place on the web of the spar.  The joy of looking at factory woodwork has been finding so many little details which we don't have to reinvent.

Thanks to John, Tony, & Rich!

Jenny Control Stick Parts

Yesterday John Gaertner and Jim Lachendro stopped buy to look at the airplane projects. I've been spending all my time lately on the Cessna 140 with vain hopes of flying it soon, soon is all relative. We went over to my brother-in-law's place where the fuselage is stored to look at it. John who's been making Jenny parts pointed out that the control stick castings were Jenny parts. I had assumed they used such parts to save money and because the planes they built before the NINE were made from surplus Jenny parts, but I've never spent any time researching Jennies. One of the parts just setting loosely in the fuselage was this Jenny casting which I don't think is used in the NINE. It was pretty dirty but with some Corrosion-X to loosen the bolts and some light cleaning it's now like new. . . There is some corrosion on the bottom of the mounting tabs where it was bolted to the plywood floor, but otherwise it's in excellent condition. One of the interesting things discovered after cleaning it was the stamps on the top of the one tab. They were probably done by an inspector or the person who machined the part. It would be amazing to find out who's stamps these were. The oiler had to soak in Corrosion-X all night to get it freed up. It now works almost like new. I'll soak it some more to treat the little bit of rust between the moving parts. It looks like it was nickel plated. Thanks for coming over guys, this was great fun, which is the point of such restoration projects after all.

100 False Ribs Done

While I've been writing all this I've also been making ribs. After 100 ribs you get very good at it. That many ribs makes quite a stack of ribs.

Now that they're done I did one more experiment. I wanted to know if this would work with 2024-T3 aluminum instead of the 5052-H32 we first selected. The 2024-T3 is much stronger but also has more spring back and I didn't think we could form the channel walls square. The 2 ribs at the top are 2024 and the rib at the bottom is 5052. Clearly the form block needs more curve to allow for the spring back of 2024 but otherwise it works fine. It does take much more force to make the ribs. The channel on the right is 2024, again no problem with the shape. Also there is no evidence of cracking along the corner radius even looking with a 10x glass.

I'll give some thought to applying the same design process to making a form block for 2024-T3. I also want to do some load testing to see if there is any real advantage to using the stronger aluminum.