There are many problems with the common M3 / M5 models produced by Tamiya, borne from the interest of saving money in mass-production and building all around a theme of motorization. Some of the best scale modelers over the last couple of generations have already written about these deficiencies extensively. One of the more subtle problems noted, but not undertaken, by modelers is the fact that Tamiya's M3 Stuart Turret is too small. This hasn't even been corrected by aftermarket detailing sets either. As this type of correction calls for some serious soul-searching, most don't attempt it. For this commissioned project, I gave the correction a shot - and this is how I approached it:

The M3 Stuart Turret has an interior turret ring diameter of 46.75 inches. The Tamiya molding is way off - partially because they wanted to make the Turret click-lock - which is standard for tank modeling - into a ring molded in on the upper hull piece. The other problem is that to make this click-lock system work, they molded in place the bottom part of the Turret itself. The Turret Ring is secured to the Hull with six rollers, that are removed to lift the entire assembly off the tank if needed. The Turret sits on a race made up of manually driven gear teeth inside the upper hull roof. When you build the Tamiya model, the Turret Ring doesn't move with the rest of the Turret when you traverse it. Probably not a really big deal in the grand scheme of things, but if you're going to open up the Turret - the pinched interior diameter becomes apparent with the click-lock in place.

One corrective approach is to cut off the entire turret ring / roller assembly from the upper hull and replace it with styrene. I pondered this decision for a long time, but it was an unattractive approach because I had already spent some time cutting away and replacing the Engine Breather Grill Housing and certainly didn't want to risk the odd-slip of the Dremel and destroy that work.

I decided to take this approach. First, I bored out the diameter of the molded in Turret Race with my Dremel tool to the correct interior diameter. Flip the upper hull upside-down. The inner lip Tamiya molded to catch their Turret is the correct interior diameter for the Turret Ring. Score along the area with a sharp X-Acto knife and break it away. Clean up with a Dremel tool and sandpaper. When you turn the upper hull right-side up again, you'll have a little lip running the circumference of the Turret Race at the correct diameter. This becomes your new Turret Race to build the Turret upon. Sure, it won't move with the rest of the Turret when you traverse it, but when you open that Turret's Commander's Hatch it creates the illusion of the proper confines of the real thing - and it is easier that cutting away that detail on the upper hull and trying to replace it all.

Inside my bored-out Turret Ring, I made a styrene Turret Race for the new Turret to sit upon. I glued this to the bottom of the Race, flush with the interior roof. The new Turret sits on a thin styrene ring cut from and reduced even more from .010" strip - I've never seen .005" strip. Lastly, I made a pattern and cut a new interior hull roof out of .010" sheet and detailed with with Grandt Line Bolts - as you can plainly see them if you look up from inside the hull. The Turret Rollers come from the Verlinden M5 Stuart Detail Set - the connectors for the Control Levers to be precise. They look quite a bit like the Turret Rollers.

Below, the Turret is coming together. I wanted originally to model the all-riveted D37812 Turret because I thought all the extra detail in an otherwise bland part would be nice - but my client wanted a Stuart in a Stateside setting just before WW II. I couldn't find photographic support for this Turret still being fitted to Stuarts by 1942, and appearing in the neat Armored Force bands and yellow National Insignia. The aluminum barrel is from Jordi Rubio, and the 37mm Gun parts are Verlinden Production items from the M5 Stuart Interior Detail Set. I used the principal components and scratchbuilt my own additions to make the unit appropriate for the M3 Stuart I was modeling. I drilled out Tamiya's M3 Mantlet Plate and Verlinden's Gun assembly to allow me to slip both the Jordi Rubio barrel and a Verlinden .30cal MG barrel through their respective openings.

The D38976 welded Turret I'm modeling sits on a Race made from .030" lead foil of the TechStar line. I cut the ring's teeth with mini-pinking shears from Fiskars - not the easiest pair of scissors to find on this planet. This allowed me to keep the traverse feature of the Turret. The foil is strong enough to endure mild handling, and flexible enough to mold into the ring for gluing to the bottom of the new Turret.

Trapping VP's 37mm Gun assembly is a pair of mounts made from .010" styrene sheet - one of which is trapped between the barrel and the coaxial .30cal Machine Gun inserted through the opening in the Mantlet. At this stage everything is tacked together so that I can better visualize what I want to do before committing to glue.

Above, a small length of styrene strip is glued to the rear upper-face of Tamiya's Mantlet to help me anchor the Turret Roof piece when I attach it later on. The beginnings of the Commander's Nest is shown here too, as are the mounting points for the 37mm Gun. The Turret Traverse (which was human-powered) is made up from a modified Verlinden Turret Motor from the M5 Stuart Interior Detail Set, a spare watch gear, and a little length of styrene rod for the crank handle. Nine bolts and nine rivets from Grandt Line are used for detailing the brackets that secured the Turret walls to the Race. Down through the Turret, the near-finished interior shows a First Aid Kit and placement decal marking it's location. Other items visible is a hook for hanging the Interphone mike and cables for the Hull Gunner and the Interphone Box in which the throat-mike set plugs into. In front of the Hull Gunner's seat is the bin that holds 250 rounds of ammo for the Bow .30cal MG. Pads were fitted in early M3 Stuarts to help cushion blows for the crew in the tight confines of the interior - which really didn't help. Like the seats, these early ones were Black Leather covered cushions, which I modeled here. Below is a closer shot of the Turret and Traverse Crank in place.

Above is the working Turret Roof piece and Commander's Nest Hatch. The three Pistol Ports and rest of the details for the Turret interior would come later - after adding the weld beads that joined all the plates. The miniature is finally beginning to look like a Stuart.