Silver Mounted Naval Academy Pistols – Finished !!! After 54 years !!! by David Crisalli: Part 6

 Getting ready to cast the ram rod pipes in sterling silver…..This shows the wax patterns attached to a sprue former

Then a ring (piece of steel pipe) is placed around the wax patterns and the investment (sort of a high temperature plaster) is vacuum mixed and poured around the patterns…..

Here is the wax pattern (attached to the sprue former) for one of the butt caps ready to invest.  I cut the spurs off because the spurs on the original that I made a mold of were too short and the wrong curvature for these pistols.  I will need to cast longer spurs and then assemble them to the butt caps before inletting onto the pistol stocks…..

Here is the pattern in the ring prior to the investment pour…..

I had time to make the first butt casting in silver.  Here it is as cast and in my gravers block to start some clean up of details…..takes more than two ounces of silver to make each butt cap.

Had a chance to cast the ram rod pipes.  When I made the brass pattern, I made it with a short cylindrical section on one end.  The intent here was to make the pipe mold so that the resulting pattern, when cast, could either have the cylindrical section cut off to be used as a forward or middle pipe, or have the cylindrical section left on so that a rear ram rod pipe tail could be attached by soldering.  I then made up a wax pattern for the rear pipe tail and cast that.  It will be dressed down somewhat and then a mold made for the tail piece so that I can pump wax patterns for both the pipes and the tail piece.

Polished the pipes some….and here is how the tail piece works on the rear pipe……Need to make a mold now for the tail piece.  Also, I may need to make two more pipes as I may use three on these pistols….

One thing I didn’t anticipate when I came up with the inserted plastic straw to form the ID of the pipes was that the heat of the melted wax and the pressure of the injector (only about 8 psig) would cause a deformation of the inside of the pipe.  I saw it before I made the casting but thought it would be easy to correct in the metal.  It was not as easy as I had thought it would be and took me quite some bench time.  In thinking about it, and deciding to add another pipe to each pistol, I came up with a modification to the procedure to keep the ID consistent and round.  I made a brass mandrel that was a slip fit inside the straw.  Now to pump the wax, I cut the required length of plastic straw, slipped the brass mandrel inside the straw piece and placed both inside the rubber mold. I jacked the injection pressure up to 15 psig and got nice, clean, wax patterns with a round, consistent ID.  I will probably recast all six pipes now with the new wax patterns.

Here is a new wax pipe with the straw and, just visible at the ends, the brass mandrel installed…...

While I was at it, I made the rubber mold of the rear pipe tail piece so that I can make two identical copies for the final pipes…... 

I have been making these types of castings in silver, gold, brass, copper, etc., for more than 65 years.  The amount of shrinkage, as is true with all castings large or small, varies with overall mold dimensions, thickness in the various cross sections of the cast part, how the mold is gated and vented, whether or not “chills” are used, and the material being cast.  In many cases with decorative items, like jewelry and the gun parts for these flintlock pistols, the final dimensions are not that critical as all the mating surfaces will be made to match the casting.  However, like making a dental crown to fit a prepared tooth, the final dimensions of the casting must be very precise and the appropriate steps must be taken to make that happen.  For parts like the silver work for these pistols, and after the noted 65 years of doing this, I can just rely on my “feel” for how things will come out.  And if I guess wrong, I just do it all over again….

Casting a few more ram rod pipes…..I may like this second set better than the first ones.

Made the casting for the second butt cap……..

Pumped waxes for the rear ram rod pipe tail pieces…..

Will get these castings done in the next few days and then install the ram rod pipes.  With those installed I will be able to finish shaping the fore stocks.  After that I’ll make the long ears for the butt caps and take on the very tedious task of installing the butt caps. 

Busy with work again…..but had a chance to cast the updated version of the ram rod pipes and to invest the waxes for the actual pipe tail pieces that I will use on the pistols…..

Six new versions of the ram rod pipes….

Using the brass insert was my initial try but I couldn’t get the brass back out of the thin wax pattern without deforming the wax.  I then cut about a 2 degree draft on a second brass insert and tried again….without any luck.  In my frustration I went to lunch at Jack-in-the-Box and came back to the shop with the straw idea.  If I were going to make a few hundred of these I would take the time to solve the problem, but this got me through making the few ram rod pipes I needed for this project.

Tail piece waxes (2 and a spare) being invested for casting in sterling…...

Not making a lot of progress these days, but if I can get the silver ram rod pipes finished, I can inlet them and finish shaping the forearm.  Here are the cast rear pipe tail pieces…..

While I was at it, I had an order for 14 karat gold submarine officer warfare specialty insignia…..here are the wax patterns…..

This is the rough casting on the full size and miniature insignia….

Had a break in the aerospace work and had a chance to finish the assembly of the rear ram rod pipes.  The tails were silver soldered in place and a rough finish completed on the pipes.

The next step is to install all the pipes and then finish shaping the fore end of both pistol stocks.  The trigger guards will be the next effort in the silver work area.

Well, the silver pipes are all finished and I got them inlet into the stock today.  One of my least favorite tasks is inletting rear pipes and it was especially difficult in this rosewood.  I think it would have been easier to inlet them into a stock made of granite !!!

Drilling for the retention pins will need to be very exacting.  The web between the bottom of the ram rod groove and the barrel channel is only about 0.080”so that is how tall the tabs are on the pipes.  Not much room to miss with an 0.062 pin…. 

Copy and photography by David Crisalli. The italic copy is David's response to a question asked on the ALR site.