Rudder Bars are Finished

 The last weld for the brake pedals added the brace for the arm.  The cotter pin on the end of the brace keep the brace on the short end of the pedal and the pedal in the bearing tube.

 I sand blasted everything I could before making the last weld, to keep the grit out of the pedal bearings.  To clean up these last welds, without getting grit in the bearings, I wrapped the bearings with paper towel and masking tape.  I also cleaned everything I could with the blast going away from the bearings.  It worked well, no grit in the bearings.

 For John's rudder bar I only primed it.  He has some welding to still do to add mountings for his brake cylinders.

I painted mine with primer and black enamel.  The drawing showed black lacquer, but I think enamel holds up better. I baked it to get a harder finish.

It's always nice to have something finished.

Sand Blast Tail Surfaces

 I can't weld 4130 outside in the wind.  While I wait for the windy days to end, so I can finish welding the rudder bar, I've started sand blasting the tail surface welds.  Since I have to do the sand blasting in my attic I've modified my sand blast cabinet.  This is the same process I used to bead blast the spar for the Cessna 140.
From doing the spar I have a hole in the side of the cabinet but it's not big enough to fit the tail surfaces.  For the tail surfaces I cut a hole in the back of the cabinet 4" high and 32" wide.  I made a plug from 2" thick, closed cell foam rubber which is 6" high by 34" wide.  The extra size is used as a seal by slitting it 1" deep along the center of the edges.  It's like a big grommet stuck in the hole.

 Instead of a big hole in the middle like a grommet I put a long slit in it for the tail surface to slide through.

 In the front I used some more pieces of foam rubber as seals to allow the door to be open enough to for the tail surface to slide through.  The bottom edges are slit like the  back plug so they seal on the edges of the cabinet.  The top just seals on  the door.

I cut vertical slits for the spar and trailing edge to fit through and reasonably seal around them.

 Inside the cabinet you work on a few joints at a time and then slide forward or back to the next joint.  Once one side is done flip it over and do the other side.

It's a little awkward working this way.  I'm only cleaning up the scale around the welded joints, so it works.

Brake Pedal Cable Clip

 The brake pedals mount to the back of the rudder bar and swing toward the center of the bar when pushed with your heel.  As a result the Clip to which the brake cable attaches is at an odd angle as explained in an earlier post.

 I used the Styrofoam model I made as a guide to make a fixture from a piece of 4x4 to make the welding fixture.  After truing up 2 faces as a reference to use in making all the cuts I cut the ends at 28 degrees, the side at 13 degrees.  The 15 degree twist was cut with the end setting on the table of the saw.

 A stick of wood across the bottom clamps the pedal to the block.  The clip is clamped in place ready to weld.

By cutting the 28 degree tilt at both ends the block works to make both left and right hand pedals.

Brake Pedal Progress

 I made a wood block, from a piece of 4x4, for a jig to hold the cable clip in position for welding to the rudder pedal, shaped like the Styrofoam mock up.  The end is cut tipping forward 28 degrees.  The side leans in 13 degrees.  The clip then twists 15 degrees.

 I carved some clearance around the weld area and clamped the clip to the block.  The pedal is clamped to the block with a stick of wood.

The block is made so one pedal is made with the clip at one end and the other end makes the opposite pedal.

 It was easy to weld with the joint very accessible.

 The bearing tubes for the rudder pedals are welded to the back of the rudder bar, parallel to the rudder bar pivot bearing, but rotated 50 degrees.

I made a block with a notch to hold the bearing in the correct position.  I clamped on a block of wood to align it with the bottom of the rudder bar.

With a cross ways block of wood I clamped the whole thing tight to the rudder bar.  It worked OK but you could only tack one side, in 2 places, then remove the block tack the other side and weld the joint.

 The block got scorched pretty good but wasn't damaged too much to weld the opposite bearing.

 All the blocks got scorched but they worked fine.

 The rudder pedals are finally in the bearings, we're getting there.

 Because some of the welds require welding on or near a previous weld so I clean each weld before making the next one.  The next parts to weld are the gussets on each pedal bearing and a piece of tubing to act as a return stop for each pedal.

 The Pivot Bearing also get a gusset which is not needed on the standard rudder bar.

 After the pedals are installed in the bearings the brace which supports the cable clip and be welded to the clip.  It just fits over the short end of the rudder pedal with a cotter pin to secure it.

 The cotter pin hole is drilled 3/32" dia., 3/16" from the end of the short leg of the pedal.  The hole is perpendicular to the plane of the pedal "L".  I marked 3/16" from the end of the tube with a pencil then burnished a line on the top and bottom of the tube.  Just rest a straight edge on one tube and gently rub it on the other tube to burnish a center line.  By center punching a hole on each side of the tube I end up with a hole straight through the tube.
I started the hole by drilling a pilot hole with the tip of a 3/16" center drill.  With a pilot hole on each side the 3/32" hole can be drilled straight through.

Standard Rudder Bar and Front Cockpit Pedestal Welded

 The last parts to weld to the standard rudder bar for my plane are the clips which hold the rudder cable from sliding along the rudder bar.  They are just small pieces of 0.095" steel with a hole drilled for a cotter pin.

I used this hole with a small spacer of 3/16" tubing and a cotter pin to hold the parts spaced and aligned parallel to each other.  A piece of safety wire twisted tight worked great to hold them while welding.  I found the 0.032" wire was easily melted with a stray torch, 0.040" wire worked better.

The cotter pin and spacers were easily removed after welding.

 I started welding the front cockpit Rudder Bar Pedestal by tacking the ring to the main tube in 3 places.  I didn't want the tack welds to interfere with the diagonal tubes.  While tacking the ring I supported it with a piece of tubing to hold it the correct distance from the end of the tube.

I drilled locating holes in a piece of plywood and bolted the diagonal tubes and base plate to it with washers to space it up about 1/2" from the wood.  The wood still got scorched tacking the base plate to the main tube.

I welded as much of the cluster as I could reach with it bolted down then removed the bolts, finished the cluster, and welded the base.

 With it welded the cotter pin hole in the main tube and top ring were drilled.  It's ready for paint.

Very cool to have a nice new assembly.  I'll use the new bar in the rear (pilot) cockpit and move the old one to the front (passenger) cockpit.

Now I need to finish John's Heel Brake Rudder Bar.

Brake Pedal Arm Position

 The brake cable, or in John's case the brake cylinder is actuated by an arm (with small hole) welded to the brake pedal.  It is supported by the brace which is welded to the arm and fits over the short end of the brake pedal.  A cotter pin keeps the brace from sliding off the pedal tube.

The problem was how to hold this arm in the correct position while welding it to the pedal.

 I realized I could use a block of wood to hold the arm in place.  I've mocked it up from a piece of Styrofoam to see how to make it.

The arm tips forward 28 degrees.

It stands up at 77 degrees, or if you will, tips in 13 degrees.

Looking from the top it twists 15 degrees from the center line of the long tube.

 Here is the result of all those angles.  I think a wood block will work.  I'll cut it away near the weld area.  Even if it gets badly scorched it won't matter because I have to make separate block for each pedal to get a left and a right.

The brace gets welded on after the pedal is installed on the rudder bar.