Pintles and Gudgeons

Day 218.

The most complex part of the rudder assembly is the hinges that allow the rudder to turn.  These hinges are made from pintles and gudgeons.  Both are basically metal ‘straps’ that wrap around the hull and rudder.  The pintle has a pin that extends down from the bottom.  The gudgeon has a tube that accepts the pin.  When the pintle is inserted into the gudgeon, it can turn freely and forms the hinge.

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On small scale static ship models, we can easily omit most of this detail.  You probably won’t let people touch or play with the model, so it doesn’t matter if the rudder actually turns.  When assembled and installed, these really just look like little straps stuck on the rudder and hull.  In the words, we could just glue the rudder in place and fake it.

However, I’m trying to learn new stuff, and this seems like a fun detail to add.

The body of both pieces will be made from brass strip, cut to the right size.  It will be a single piece that is bent in a few places so it can wrap around the rudder or hull.

The holes in the body are for the bolts that would have held these in place on the actual ship.  My plan is to drill those holes before I bend the strips.  Those holes will be tiny.  After the pieces are installed, I’ll fill those holes in to simulate the heads of the bolts.

I’ve decided to use brass tubing on both the pintles and gudgeons.  I think this will create a more uniform look, and will help line things up.  The tube on the pintles will have a thin brass rod soldered in to form the pin.

I tried a few different ways of making the pieces out of brass strips.  Getting the holes positioned correctly is difficult.  To make things a little more complicated, the length of each piece is different depending on its location.  To make things a lot more complicated, the thickness of the rudder and sternpost varies according to location.

The approach that worked the best for me was to cut a piece of wood to use as a building board.  I marked this with 6 straight lines (1 for each of the 3 pintles, and 1 for each of the 3 gudgeons).

I used my dividers to measure the thickness at the three points on the rudder and on the sternpost, and transferred each of those to the board.  This gave me markings indicating the back flat end of each piece.  Next I measured and transferred the lengths of each piece from the plans, marking it for each side of each piece.

I cut brass strips that were longer than needed.  I used the extra length to glue the pieces down on the board.  I need these pieces to be very secure during the drilling process.  Finally, I marked the positions of the holes I was going to drill.

Holes were drilled using a small Proxxon drill press and a compound X/Y table.  The compound table lets me move the piece around in fine increments by turning some dials.  This helps to get the position of each hole very precise.  I drilled the holes with a #64 drill bit.

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Brass strips were glued to a board to keep them steady during drilling.

Once all the holes were drilled, I had a nice set of strips.  Using a #11 blade, I scored the strips to note the length and the places where they would be bent.

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Drilled and marked brass strips, each a different size based on where it will go on the ship.

Next I removed the strips one at a time.  Each piece was cut to the right length, then bent to form a ‘U’ shape.  To keep my pieces straight, I modified my board by adding some thin wires that could hold the pieces while I worked on them.

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One by one, pieces are removed from the board, cut to length, and bent to shape.

Each piece was tested on the ship to make sure it fits correctly.  This is much easier to do now, before the other pieces are soldered on.

Now it is time to do some soldering.

I  cut some short sections of brass rod and brass tubing.  These were not provided in the kit, but I was able to find some at my local hobby shop.  The brass rod I used was 0.032″ in diameter.  The brass tubing was 1/16″ in diameter (outside).  The rod slips perfectly into the tube.  I cut these sections about an inch or so long.  They will be trimmed later.

Each piece needs to be soldered to secure the rod to the brass strip.  This is my first ‘real’ attempt at soldering.  I did a bunch of reading, and it sounds like most people prefer ‘silver soldering’, but that is more involved than basic soldering.  I’m going to keep it simple and just use a normal soldering iron, solder and flux.

I used two ‘helping hands’ (tweezers mounted to a heavy base) to hold the pieces in place.  To help hold the brass tube in place, I placed it on a longer brass rod that we’ll pull out after soldering is complete.

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Each piece will have brass tubing soldered on.

Soldering was pretty simple:

  1. Brush on a little flux on the top of the strip and the bottom of the tube.
  2. Position them so they touch, making sure they are aligned right.
  3. Cut two tiny pieces of solder, and set them on either side of the tube.
  4. Touch the soldering iron to the underside of the joint, heating the brass strip and melting the solder.
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A completed simple solder.

This process was repeated for each piece.  Care was taken to not mix up the parts, since each of these is for a specific spot on the ship.

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The pieces go right back to their assigned spots on the board after soldering so they don’t get mixed up.

Once all 6 pieces had their tubes, I went through and cut the tubes down to size.  I did this with some flush-cut metal sheers (similar to these).  Using sheers to cut these distorts the hole in the tube, so I then used a simple reamer to open the hole back up and correct the shape.  The cut was then filed smooth with a file, as were the solder joints.

That completes the gudgeons, but the pintles require another step to make the pins.

Each of the pintles got another pass with the soldering iron.  I brushed a bit of flux inside the tube and on a small piece of brass rod.  The rod was inserted through the tube, then solder was applied to fix the pin in the tube.  This was messy, but it worked.

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Brass rod is soldered into the tubes on the pintles.

The short end of the rod was then clipped off and filed smooth.  The longer end was left long – it provides something to hold onto during painting.  I’ll trim those to fit when I start the installation.

The finished set of pieces were kept organized on a small jig I made.  Since these are sized to specific spots on the ship, I need to keep them in a known order.

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Completed pintle and gudgeon pairs.  They are shaped according to their specific spots on the ship.

The pieces then got a nice coat of flat black paint.  Another option would have been to use a chemical blackening solution, but I didn’t have good results with that when I tried.  Note that I only painted the outside of the pieces.  Painting the inside would just reduce the effectiveness of any glue I use.

Once the pieces are all painted, we’re ready to start the installation.

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The rudder, pintles and gudgeons ready for installation.