Cable Splicing Clamp - Holding Plate

 The presser bar pushes the cable loop and thimble securely into this plate, which does the actual holding while the loose end of the cable is secured.  It is made from a piece of 1/4" x 1" x 3" mild steel bar stock.

 The hole Locations are transferred from the base plate with duplicating punches to assure the bolts will align well.  The center hole is not drilled it is just a reference point.  The 2 bolt holes are drilled with a #3 drill and tapped with a 1/4" - 28 UNF thread to accept the 1/4" bolts.

 The opening in the center is to hold the loop of cable and the thimble so the hole is tapered to match the thimble.  From the AN100 drawing the sides slope 1:3 so rather than move my nice square table, and have to realign it, I made a hardwood block 1" x 3".  The plate is set on top of it and  held with the wrench while drilling.  The bolt is just there as a stop to keep the block of wood from sliding.  Think of it as a bench dog.  The holes are drilled through with a #2 (3/16) center drill.  Before drilling at the angle I drilled with just the tip about 1/32" deep 5/16" apart.  I chose the 3/16" drill because I plan to use this with 1/8" and 5/32" cable but this would allow up to 3/16" cable to set nicely in the round groove.

 All of the cutting and drilling is done with the bottom side of the plate up (visible).  The edge of all the cuts are more sharply visible on this side and the saw work is all being done by eye.

 The entrance slot and the relief for the thimble are cut next without ant taper.  This is just to get the shape.  From the top side you can see the angle of the drilled holes better.

 The band saw was used with the same 1:3 block to taper the thimble relief by placing the block next to the blade for good support.  The saw is being used more like a powered file than as a saw.  You just gently saw into the plate until the blade just kissed the cut edge.

I also tapered the entrance hole by turning the block 90 degrees to the blade and sawing along the edge of the cut.  Again you could tilt the table but that would have taken longer then making the cuts.  This came out really good and the cable fits perfectly.

The two 1/4" bolts were threaded down to 2-5/8" from the head.  It doesn't show here but they were cut off to leave 1/4" of good threads to screw into the plate.  The center bolt was threaded to give 1-1/2" of threads.  The head will get cut off from it later.

Cable Splicing Clamp - Clamp Base

 This part is made from a piece of 1/2" x 1" x 3" mild steel bar stock from Tractor Supply.  The 1/2" pivot hole is centered 3/8" from the edge.  The two 1/4" holes for the slider bolts are 7/32" from the ends and 1/4" from the same side as the pivot hole.

 To make sure the bolt heads don't catch on the vise in use the bolt heads are recessed into the base.  An easy job with a milling machine.  I created the same result with the band saw.  You need a sharp blade and a guide to control the location of the cut and the keep the bar parallel to the blade.  Just put on a noise cancelling head set and a good book because this needs to be done slowly.  Forcing the bandsaw will cause the blade to wander.  A careful cross cut and the ends are done.

  The ends have a 1/4" radius and the big curve is just tangent to both ends and the middle of the bar.  The shape was rough cut with the band saw.  The final shaping was done with the belt sander and and a mill file.  All the corners were softened.  I think I'll grit blast all the parts when I'm done just to even up the finish.  I don't think it will make sense to paint such a tool. I'll just need to keep it lightly oiled.

Splice Clamp Support Block

 When I grind with the belt sander I am careful to set the table and miter fence as square as I can get them.  Then to minimize uneven grinding I make a couple passes and then rotate the part 180 degrees and make a couple passes.  If you use light pressure you can do a very good job of it.  The center for the pivot hole was then located on one end of the blocks.

 Before drilling the hole down the split between the blocks I used the bandsaw to create a guide hole to help the drill go straight down the center.  The saw cut was made about 1/32" deep.

 The centers for the screw holes were laid out 1/4" from the ends and 3/16" from the sides.  The blocks were then clamped together and the screw holes drilled with a #26 drill (tap drill size for 10-24 UNC threads).  To control the drill better I like to mark the hole with a spring loaded prick punch and then improve the mark with a center punch (fits the drill better), and start the hole with a center drill.  In this case I used a #2 (3/16) center drill.  Once the holes were drilled through I drilled a clearance hole from the screw head side 9/16" into the block, a little past the center split.

 The holes were tapped for 10-24 threads.  By working in the same direction that the screws go, the clearance hole helps keep the tap going straight in.  With the holes tapped the blocks were separated and the screw holes countersunk for the flat head set screws.  I used stainless Allen head screws so I could torque them easier than Phillips or slotted screws.  The screws are arranged so 2 install in opposite corners on each side.

 With the blocks screwed together, the pivot hole was drilled.  The hole was started with a #3 center drill ( 1/4") until it the hole edge was about 1/32" deep.  It was then drilled through with a 1/4" drill following the saw cuts.  Unless you own a drill vise or finger wrestle regularly with Superman, the wrench lets you get a good grip on the part being drilled.

 The hole was then increased at the start with a #4 1/2 center drill (3/8") about 1/16" deep at the hole edge.  The shape and short length of center drills minimize how much they can wander. The hole was then finished with a 25/64" drill to give clearance for the 3/8" bolt.  The steel bushing from Lowe's is 3/8" ID x 1/2" OD x 1-1/2" long.I need 9/16" sticking out the end for the 1/2" support piece and washer between the parts.

 The 1/2" hole for the bushing was drilled 15/16" deep after opening the start of the hole a little more with a #5 center drill (7/16").

 To get this block to clamp the bushing the mating faces of the blocks were ground down until there was about .002" gap with the bushing installed in clean parts.

 The screw holes and the busing interfere so a notch was filed in each side of the bushing the allow the screws to clear it.

The parts were then cleaned in MEK to get rid of cutting oil, etc. A little Krazy Glue was used on the bushing to secure it to the blocks.  The screws were secured with Threadlocker and tightened to squeeze out the gap between the blocks.  The edges of the block were then ground to remove the little bit of the screw heads sticking out past the edges.

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.