Changes to the gun cradle

The gun cradle is inaccurate in a number of ways; here are some comparison photos to help point out the differences.

 

 

 

As you can see, the center reinforcement brace does not extend completely from side to side, is hollow, and is higher than the real Pak 40. The center pivot point is open and has no castellated nut or washer/plate detail. The pivot arms sit inside a wider, hinged clamp apparatus that has a machined fork to create the female side of the hinge. Also missing is the elevation gear box and transmission arm. With the gun in place, the elevation gear box and transmission arm would be very difficult to see, especially with the reinforcement brace filled and modified to extend from side to side. Another obvious difference is that the side walls are much thinner than the real McCoy and there is no partial ‘S’ indentation on the left side below the pivot hinge clamp.

I modified my cradle by adding a laminate to both sides of the reinforcement brace. These laminates were identical, and included the missing center section.

 

With the laminate in place, the hollow space was filled with balsa wood, which was glued in place and then cut down to match the brace shape. You can also see that the separation line between the two halves of the cradle was filled on the rear side, and the center pivot opening filled with a piece of sheet plastic cut to shape and glued in place.

 

I created a castellated nut by making notches in a regular nut with a hacksaw blade. A small section of a machine screw was cut off, run through the nut and then glued to a washer and the center pivot point. Without ‘thickening’ the side walls and floor, there is not sufficient thickness in the gun pivot points to fabricate the hinged clamps present on the real Pak 40.

 

 

I haven’t figured out yet what the tank on the back side of the upper trailer shield was for. My first belief was that it is an air reservoir for the trailer brake system, however I found a picture on Tanxheaven that showed the tank has a filler type neck towards the right end, which is missing on 21st Century Toys’ Pak 40. This would lead me to believe it is a hydraulic type reservoir, such as for the gun recuperator. What ever it is, the securing straps are molded too large and mounting bracket over sized and round. I sliced off the tank, ground down the straps to make them go all the way around it to a smaller, cut down mounting bracket. I used four 0-90 bolts to attach the tank back to the smoothed up and filled upper shield. A small piece of plastic tubing was used as a filler neck, and the end cap of an ink pen was used to replicate the tank cap.

 

 

Although hard to see unless you zoom in, this picture is the one I found on Tanxheaven that shows the tank on the back side of the upper skirt shield with the smaller anchor bands and the filler neck, but missing the cap.

 

 

This photo of the tank shows the 21st Century Pak before modification with the large rounded mounting brackets and no filler neck.

 

 

Picture of the modified tank with filler neck (no cap yet) ready to be bolted to the back of the upper skirt shield.

 

 

 The shield skirts as molded by 21st Century Toys have square lower skirt corners, large toy-like shovel mounting brackets, a US army BII shovel instead of the long handled German shovel, and no lower skirt latch and catch to hold the lower skirt up while in transit. I pulled out all of the toy-like mounting brackets, and filled them with scratch plastic slightly thinner than the skirt and puttied to a smooth, level finish. I rounded the lower skirt corners off with a file, and fabricated a new shovel securing strap fabricated from brass (bowed, the end sections bent to form flat mounting surfaces for 0-90 bolts to anchor both ends to the skirt).  A raised anchor bracket for the wooden handle end of the shovel was made from brass from scratch and likewise bolted to the shield. A lower skirt catch was fabricated, and a square hole fabricated through the lower shield through which the end of the catch could pass; this catch was bolted in place with four 0-90 bolts. A latch for the catch was fabricated from a section of plastic ‘I’ beam, brass rod and tubing. The latch passes through a mounting bracket made from flat plastic, plastic and brass tubing. The upper skirt shield is bolted to the frame mounting brackets with conical bolts on the real Pak 40. This is simulated on the back side by two round knobs where two conical bolts per side would be. I filed a small flat section on the knobs, and drilled a small guide hole through the flat section. Once the holes were drilled, the knobs were filed down to simulate flat washers. Nuts, with small bolt screw studs passing through them (the screw head being cut off with a hacksaw) were glued on the back side of the frame mounting brackets centered on the small guide hole. As a finishing detail, hexagonal resin pieces were placed in a drill and filed down to make four large conical bolt heads (thanks to Dirk for the recommendation) which were then glued, centered, on the “flat-washer” remains of the four knobs molded by 21st Century Toys. A hand made shovel blade fabricated from tin was given a wooden dowel handle to replicate the German BII shovel, as the short US BII shovel was totally out of place on the Pak 40. A final detail, outlined earlier, was the tank modification on the back side of the upper skirt shield.

 

 

 

Picture of the original skirt shields with toy-like shovel mounts removed and a rudimentary square opening fabricated in the lower skirt through which the end of the skirt catch will pass.

 

 

Photo showing how the catch will pass through the lower skirt shield from the catch mounting bracket. The first catch I fabricated was from a section of this brass ‘C’ channel with a notch filed in it for the the latch to set in and hold the lower plate up, based on photos sent to me by Dubar. After comments from Dubar, I went back and fabricated a new catch from a section of plastic ‘I’ beam as the handle.  

 

 

You will note, that there are differences in plates/catches/latches.  The catch and plate system photographed by Dubar above does not pass through the lower shield itself, while others do.  To make my Pak 40 look like others I have seen, my catch passed through the lower shield.  This positioned the latch on the back side where it was less likely to be damaged by incoming rounds/shrapnel, and is the reason I believe many are in this type configuration, which is shown in the photo below (conical bolts only thing appearing on outer side).  It is also possible, in the restoration of gun above, that the latch was inadvertently bolted on the wrong side and the angle of the photo obscures the square opening? The picture below also shows a small bracket on the underside to which a small, round reflector was mounted.  In this restored Pak, the bracket anchors the top of a slow vehicle emblem.  This picture also shows to good advantage the rounded lower corners, shovel handle clamp, and the rear tail light mounting bracket.  The bent angle piece by the shovel clamp prevents the shovel from backing out of the bowed strap on the other end. 

 

  

 

The final version skirt catch. Also visible are the new tank mounting bolt holes and the upper shield to frame bolt hole "washer".  The washer was fabricated by filing down the rounded knobs that represented a bolt.  Conical bolts, created as described above, will be glued over the washer to cover the hole.  In the lower panel you can see the 0-90 bolts that hold the latch to the back side.  When the panel is raised, the latch is pushed to engage the slot in the catch and hold the panel up in the travel position, as shown below (nuts not yet added).