Idea and Inspiration
In the background of a show I was watching there was a quick shot of this clock that appears to be based on an inert anti-tank mine. Through casual browsing I couldn't ID it other than being an anti-tank mine. I liked the vibe and wanted my own AT wall clock. Here in the US of A weirdly enough I could only find eastern-bloc TM-62 landmines and frankly I'm not putting that on my wall, so I was left with 3D printing a US mine replica to use. There are two common heavy AT in the US service, the M15 and the M19. The M19 is basically a metal can full of comp-b with a pressure plate. The lesser-seen mine, the M19, is a less-metallic mine as it only has two metal parts which weigh a few ounces. It's also a big ol' plastic block of comp-b. I liked it, so I decided to go with it.
As for the actual mechanical guts I decided to do nothing fancy and just use those cheap quartz based clock mechanisms you can find on Amazon for 7 for $15.
Successes
1. It was quick
I didn't want to spend too much time on this, so I didn't. Designed it one night and spent the next day printing it off. Spent another day with bondo, epoxy, and paint to get it together and called it done.
2. Matches the idea
Very rarely do things turn out well and match my original idea. However, where this was a quick project with minimal planning there wasn't much time to allow the project to deviate from the base idea. It's also mostly dimensionally accurate. Thanks to bulletpicker.com I got some kinda-detailed drawings of the mines. They are far from perfect, but when you are making a clock, it's more than enoughtFailures
1. The bondo-job sucks
Whew, I am not a bondo or drywall patching guy. this is my second time attempting to use bondo to hide seams. From afar and at glance, it's passable, but up close it rapidly falls apart. I really need to add a chamfer near edges that will get bondo'd and stop using their glazing putty as it has a tendency to shrink and crack like this has.
2. The mechanical connections sucks
Not going to lie, I was over confident in super glue's ability to hold this thing together, and I was wrong. I added tabs to the quarters that I thought would be sufficient but while gluing it had a lot of flex down the sides. To remedy this I used some scrap wood from laser cutting and used it as a tie on the sides, but this time with some epoxy. For version 2 I'll need to add some mechanical connections at the far side of the edge to keep this thing square.I also wanted this unique mechanism for the fuse/clock holder where it could be easily removed just like the M606 fuse, but with overhang dimension issues, bondo, and paint there just wasn't enough clearance so I just cut the tabs off and epoxied it into place. Sure I could have sanded down the mating surfaces enough, but it's a quick project that's going to be seen by like 10 people, tops.
Summary
Overall, I am satisfied. At the end of the day, I have an anti-tank landmine wall clock on the wall. Could it be better, sure, but it's a unique item that I can call mine. It didn't take too much time or too many resources, so a project manager would call that a success.
Now only if I had a AA battery...