Making extremely tiny fittings

[BETAQDAVE]

     I am trying to make a matching pair of fairleads for the stern cap rail of my 1:96 MS Phantom as shown in the actual size sketch below.  (I drew it at ¼ actual size and reduced it down to the scaled size needed.)

     My first idea was to print the scaled drawing on paper as a pattern and apply it to a 1/32” thick piece of aluminum bar stock and cut and shape it with drills and files, but the needle files that I have, aren’t nearly thin enough to get inside the hooked ends to file them down.   So my next attempt was to make them according to my notes shown below here. 

     The hooks were made from some 1/32” square brass stock that was bent over a piece of 3/64” hard wire and being cut off as shown.  The base was cut from a piece of 1/64” thick strip brass.  I tried joining the pieces with AC but to no avail since the assembly was just too weak to take any stress applied by trying to file it to shape. Silver soldering seemed to be my only other choice available.

    However, clamping such veeeeeery small pieces in place for soldering can be just about impossible since regular clamps would be much too large.  When using a torch the flames air flow causes the tiny pieces to shift around.  Touching a soldering iron to the pieces will do the same.  I considered making a jig to hold them by carving a recess into a piece of wood for a tight fit, but I would have to make one for each of them since getting the solder to melt will just burn the original jig.  I’m not aware of any other material that could be formed to make such a jig that also wouldn’t just melt or burn.                       

    Another method that just occurred to me would be to flatten the bottom edge of some hollow brass tubing and solder them onto a piece of brass bar strip using the solder as a fillet.  Then I could  make the vertical cuts to open the gap at the top of the fairlead.  But, once again that still leaves the problem of holding those tiny pieces together while soldering. 

     Any suggestions on keeping everything still while soldering them together?

[Kris Avonts]

Hi Dave,

 

Indeed small parts are a real challenge.

In your case I would do the following steps:

 

Its just an idea, I have no experience with soldering such small parts.

 

best regards,

   Kris

[Gregory]

My thought would be to make one piece, then cut and shape after it is in place.    More friendly than using two small pieces.

 

[mgdawson]

Hi Dave

I've seen methods comparable to that suggested by Kris except you don't trim all the excess off, drill holes in your cap rail and glue the extensions into the cap rail holes, much stronger than just gluing on top.

 

Likewise a jig for soldering would be a simple piece of wood with a couple of holes drilled in it, perhaps another piece of wood pressed alongside in the unlikely event the horns try to turn.

 

As fairlead horns are usually oval in cross section I'm wondering if round rather than square stock would be closer to the mark, a wipe on the outside with a file/fine sanding stick would give the impression of a more oval shape and with round stock you wouldn't need to square out the holes in the base plate.

 

Mark

Edited February 22, 2020 by mgdawson
added jig

[davec]

I think your idea about doing it in one piece still make sense, but you need something different from a needle file to shape inside the hooked ends.  Escapement files are smaller than needle files, and might fit.  You could also try a jeweler's saw with a blade the same thickness as the notch.

 

If you go down the multiple piece route, would not try to punch square holes.  It would be easier to use wire of a diameter that could be filed down to the right shape and thickness.  Would drill holes for the wire, and solder the wire in place then file the shape and bend it into place.  Would probably need to silver solder to have a strong enough joint.  Could also shape and bend the wire separately, then solder into place.

[jud]

Might be a good time to look into the Lost Wax method of casting.

[Moxis]

One more method which I have used a couple of times:

 

 

 

[BETAQDAVE]

    Well since the Pandemic arrived, I had some spare time to model the fairleads.  I took a 1/2" wide strip of 1/32" thick brass to my machinist vice with a paper pattern of the desired shape glued to the face.  Using a jewelers saw and my skinniest files, I cut the shape out.   It took quite some time before the shape was acceptable, sawed them loose from the strip and coated them with Brass Black. 

    With the fitting being a mere 1/32" thick I didn't think glue alone would be able to anchor it to the rail.  So two pieces of 1/32" brass wire were taped down to the face of my basswood deck pattern along with the fitting to keep them still while I soldered them together with a soldering iron.  Then when done the wire was cut to length as shown in the upper right of the photo below.

    Once the fairleads were cleaned up with my files they were given another bath in the Brass Black and set aside to dry.   I located the desired position of the fittings by using the wire pins to put impressions in the cap rail to locate the holes.  A pin vice was used to very carefully drill holes for the pins.  Using a touch of medium CA on the ends of the pins they were pressed in place to let the glue fully set. 

    So below is a photo of the fittings in place. 

    I wasn't totally satisfied with the fittings, but as my dad always used to say: it's good enough for government work.

    

[kurtvd19]

I had to make this same kind if fitting.  The steps I used are shown in the photos.

Small files were used to round off the square edges.  Polished and then plated.

 

[BANYAN]

Thanks for sharing this Kurt, you have just given me the solution for making 'cheek blocks' for the yards and bowsprit of my model   A small modification, drill a hole for the sheaves and not open the top, a bit of rounding with a file  and hey presto.

 

cheers

 

Pat

[Patrick Matthews]

Exactly, Kurt... 'tis easier to "carve" many parts from solid, rather than assembling little bits. A mill is not required... a drill press and a jeweler's saw will often get you 90% of the way. Files and polishing for the rest.

 

Myself, I now 3d print most of these parts (waxes actually, which are fed into lost wax casting). Below: A tree full of printed cleats. The color is misleading, they are unplated brass.

 

[kurtvd19]

Pat:

Are you doing the casting or farming it out?

 

[Patrick Matthews]

I support the economic principle of "division of labor"- I let the pros do it! This example was from Shapeways.