December 26, 2022

AN-M64 500lb Bomb

This is another replica WWII Bomb just like my AN-M30 100lb Bomb but this one is a AN-M64 which is a 500lb version and it is also true 1/4 scale this time.  I actually designed this back in 2016 and printed out some of the pieces at the same time as the 100lb version but I never got around to actually starting the build until Dec. 2022.

The design is pretty much that same as its little brother but I did have to start from scratch when designing this one.

The over all shell is hollow and will be printed in several pieces.

Here is an exploded diagram of all of the pieces and parts of the project.

Back when I printed the first set of parts I was still pretty green at 3D printing and design so the parts are very rough.

The first step was to superglue all of the three main casing pieces together.

This is after gluing them together and there are some rather large gaps but also the shape of the cylinders is pretty rough because I didn’t export the STL’s in a fine enough resolution so this is going to require some work to clean up.

After sanding a long time with 80 grit paper they were still in pretty bad shape…

… so it was time to add some Spot Putty as a filler.

I went a little crazy but at least this stuff is pretty easy to sand but makes a huge mess.

Here it is ready for primer.

Here is another set of parts using a much fine resolution STL, I also added a joiner ring to the tail cone piece to eliminate some printing supports. (The multi color casing was just me using up old filament.)

The ring just gets glued half way into the main casing before gluing on the tail cone.

This helped clean up the gap that that last one had.

Here is the finished second body.

This was also sanded with 80 grit sand paper before applying a much thinner coat of Glazing putty. (not shown)

This is how I printed the tail fins although I think they would print upside down too. (I might try that next.)

Here they are after a rough sand.

I won’t bore you with the priming and painting but here it is with the main base coat of OD green.

Next is was onto the lugs. I printed these laying down (so they would be stronger), on a raft, and jacked off the bed with supports.

The lugs were then painted and glued on in to the main casing.  (I still may go back an add the simulated welds around them.)

Next it was time to paint the yellow nose and tail markings.  Using a compass I drew out the appropriate sized  circle on some masking tape and then cut it out with a razor knife.

That was then stuck onto the nose cone trying to keep it centered. (It doesn’t have to be perfect because I’m sure no one cared during the war if it was off centered or not.)

The same was done for the rear and more masking tape was used to control over spray.

The finished markings.

Next I printed the parts for the AN-M103 Nose Fuses.

They still need a little more clean up and paint but they don’t look to bad to the naked eye.

The vanes were bent by just heating them for a split second with a lighter and then bending them by hand and letting them cool in position.

Here is the finished Nose Fuse after a little paint and assembly.  The vane was attached with a tiny 0-80 x 1/4″ screw which is hidden under the paint.

Here are all of the parts for the AN-M100A2 Tail Fuse.

Here is what it looks like when assembled…

… and here it is after paint and  installing it in the the read of the bomb casing.

Here is the back side…. The tiny hole is where the Arming Wire will go.  The arming wire keeps the vane from spinning in flight, the wire will be yanked out once the bomb is drop allowing the vane to spin and in turn arm the fuse after the bomb falls far enough away from the plane.

One of the last thing to so was added the lettering. I printed up some thin stencils to allow me to airbrush on the letting.

The stencils were affixed with some masking tape in sections before spraying.

Here’s how it came out… overall it’s not to bad but using the very top stencil on the curved nose come was a little challenging and each line had to be done separately.

I didn’t like the larger fonts on the bottom so I redid it. (For you B-17 guys there are some “Easter Eggs” in the numbers… comment if you know.)

This is the finished AN-M64 Bomb. I still might distress it a little but for the most part it’s done.

The dual lug side.

The AN-M103 Nose Fuse.

The Tail fins with the AN-M100A2 tail fuse.

Over all it’s about 14 11/16″ tall standing up.

Here it is back in 1943 ready to be loaded onto a B-17.

While I was at it, I designed a B-11 shackle to go along with the bomb… this mead me down a Rabbit Hole of a much larger project for this thing.

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