Aliens M40 grenades in wood on a homemade lathe

[Dan Efran]

Several years ago (sigh) I started turning a spare power drill into a DIY wood lathe. That project stalled after a while, but I revived it this year and the lathe, though crude, is up and running.

My main excuse for finally finishing my lathe is that I got the Nerf Aliens Pulse Rifle. I’m going to repaint it (of course) and I need some grenades to go with it. Turning out (literally) a box of M40s is a perfect project to get some practice using the lathe.

First step was a freehand proof of concept, trying out the lathe for the very first time. Turned from a 1-inch poplar dowel with a regular wood chisel, an old drill bit, and sandpaper.

(I’ll have to make a few turning tools.)

 

[Dan Efran]

Quick and dirty knurling on the proof of concept, pressed in by hand with a screwdriver tip. I’m going to need a better way to knurl.

 

[Dan Efran]

Good old Rub’n Buff completes the proof of concept. (I only had gold RnB on hand; I need to get some more colors.)

I’m very pleased with how this is going so far!

 

[Dan Efran]

Silver Rub ‘n Buff over the gold.

I created a “primer” by pressing metal tubes against the bottom end to make round grooves. Gold RnB on that bit.

Not bad for an off-the-cuff prototype. I need better turning tools for the real ones though.

 

[Dan Efran]

With the second prototype I tried to get the shape and size closer to correct. It’s too long and very slightly too thick, but pretty close. I definitely need better tools and maybe better wood, but I’m cautiously pleased so far.

 

[Dan Efran]

Slightly better turning tool, slightly better results. This one is pretty much the proper size and shape.

I’ll have to make a few little adjustments, but it seems like my lathe can handle this job.

Wood grain is going to be a perpetual challenge…I’ll probably make a few more and start experimenting with finishes. Maybe a filler primer or some polyurethane or something to smooth out the wood texture.

Still need to think about the pop-off plastic caps, which seem a little bit hard to source. I want at least a few really removable ones—I want to see if I can achieve a good fit—but I’ll probably also make some with the cap just sculpted on.

This is starting to feel less like an experiment, and more like a nearly completed project.

 

[Dan Efran]

I realized that my second test piece was too long in just the right place for me to saw it open, drill it out, and make it into a clicking version the same size as my third, more accurate one.

Pen spring. Bit of 3/8” dowel. Slice of bamboo drinking straw.

 

[Dan Efran]

 

[Dan Efran]

The version with a pushable button works so well, I figure I’ll want to make a few more at some point. Luckily I have a big box of pens waiting to be recycled. I raided it for springs, something I honestly should have done a long time ago.

I’m a little surprised at how many different sizes of pen springs I found.

I also scored some cool greebles for other projects.

It’s easy to get carried away with this kind of stuff, but when you like building weird stuff cheap, it’s important to cultivate a useful collection of random greebles.

 

[Dan Efran]

I tried making one with a sculpted-in “cap”, with some miniatures paint I had handy.

It looks awful. The matte paint and some slight asymmetry makes it look like lipstick.

If I take more care with the turning and use a more appropriate paint, I hope I can get a better result, but it might not be easy.

 

[Dan Efran]

A little side project: the box.

MTM brand box with the branding painstakingly sanded off, from emery boards down through 600, 400, 1200, 2000, then Novus #3, #2, and #1. (It was frosty looking right down to the final Novus polish.) I particularly wanted to get rid of the "www" at the bottom....

I didn't bother painting a box that's already close enough to the screen-accurate color in my opinion.

Decals ordered from spatcave. Affordable, easy to apply, plenty accurate enough for me.
I'll spray a matte finish over them, for durability, when the weather is suitable.

For now, the box is complete.

 

[Tan Djarka]

The grenades are pretty cool, but a homemade lathe? I'd like to hear about that!

 

[Dan Efran]

The grenades are pretty cool, but a homemade lathe? I'd like to hear about that!

Yeah, well, I didn’t want to buy a lathe. Lathes are expensive. I’m cheap. But every so often I want to make something round. You know how it is.

At some point I had to drill a hole in a brick wall. My regular power drill couldn’t do it, so I had to buy an impact driver. It has a regular drill mode too, but it’s bigger and more powerful than I usually need, so it became a spare drill that sat around doing nothing most of the time.

I remembered that in a pinch you can chuck a bit of plastic, wood, or even metal into a drill, and sand or file it into a different shape. For example you can turn a hexagonal bolt head round, or sculpt scale model tank shells from milliput or whatever.

So I figured it would be plausible to turn my spare drill into a basic lathe. I further figured there would be multiple versions already on YouTube, and sure enough, after watching a few videos on the subject, it looked even easier than I expected.

Of course, I didn’t want to do it the simplest way or follow someone else’s plan exactly. I developed a plan. I worked out a scheme where I could convert the “drive unit” into a disk sander too, with a pretty quick change between tools. I got the disk sander configuration working first because I needed it more….

…and left the project there for years. The sander has been very useful (I don’t have a proper bench grinder or anything) but the lathe was just some parts kicking around the corner of my workshop. I knew what I would build and had most of the parts and materials, but it just wasn’t a priority.

Then I heard about the nerf pulse rifle, got one, and started thinking about grenades to go with it. That sounded like a fun project…for someone with a lathe. So I finally finished it as originally planned. I’ll make a bunch of M40s as a proof of concept project as I practice using it, get it tuned up and tricked out, and experiment with homemade turning tools.

As for the details of the lathe itself, I’ll try to put together some pictures soon, or maybe even a video, but meanwhile you can get the general idea by searching for “DIY lathe” on YouTube. Mine is pretty typical of the genre, overall.

 

[Dan Efran]

Just a small update on this. I found someone selling nice-looking 3D-printed M40's online. I mostly don't like 3D printed stuff, but I eventually decided to get half a dozen of these to try them out, and to compare the measurements on my wooden ones.

These plastic ones are quite nice. They do look and feel like filament printed plastic, but the metal-look plastic has a pretty nice sort of brushed-aluminum look that, while not perfect, gives this prop the right general kind of shiny appearance. The button can be pressed; the action feels good, but makes a somewhat dreadful scritching sound. The cap pops on and off with a very satisfying click. I don't know if that fit wears out over time, but for now it's perfect. The detail on the knurling looks fantastic. There is a seam of sorts down one side, I guess where the printer changes layers. Overall, a very respectable replica and a great value.

I still don't like 3D prints, though. I'm thinking about maybe turning a master from plastic on my homemade lathe and then casting up some resin copies. Someday.

Anyway, the main reason I got the plastic ones was to double-check my wooden ones. So how do they compare?

Really not bad! Very close measurements overall. None of mine are exactly the same, but they're clearly all pretty close to correct. Looks like the one on the left is the most accurate overall. It's clear I could get even closer with a bit of practice and better materials.

In fact, with just a bit of forcing, I was able to get the cap from one of the 3D printed ones onto one of my wooden ones.

It's not a perfect fit, but I got it on there without even damaging the finish. I think that shows that the wooden M40 experiment is a definitive success.

So what's next? The wooden prototypes were a lot of fun to make, especially the one with a working button. I proved to myself that I can turn these on my lathe, and get them looking pretty close to correct without too much trouble. They're a great little project to test out lathe tools and materials, so I expect I'll make a few more eventually. Now that I have a good physical reference for comparison, I can try making them increasingly accurate. But until I upgrade to better materials, mine won't look as good as the 3D printed ones. (And I might have to make a knurling tool.)

Eventually I'll fire up the lathe again, try out some new materials, and if I get really good results, maybe move on to molding & casting; but for now, I'm calling this project complete. Next Aliens-related project coming up: motor bypass circuit for the Nerf pulse rifle, so I can actually hear the sound effects.

 

[DN12742]

I completely agree that 3D printed products without paint - "have no" soul.

The only thing that is good about 3D printed products is the evenness of the shape. The uniformity of the surface. And even then, it depends on how the modeler exported the model, from the design program. Sometimes you download a free model, and there is such a low number of polygons that you take it, unpack your favorite design software, and do it again.

Although - the model is not bad, it was just poorly exported.

Often, FDM plastic for printing without paint - cannot convey the feelings when you see the final result.

Sorry, this is not a product of the replicator from "Star Trek".

This is a cheap craft, it has no soul.

I really liked your method of reproduction, and I, like the respected Tan Djarka, I would like to see your tool park and your lathe.

 

[Dan Efran]

I completely agree that 3D printed products without paint - "have no" soul.

The only thing that is good about 3D printed products is the evenness of the shape. The uniformity of the surface.

Well, that's not quite how I would put it.

What's good about 3D printing is (1) you can iterate prototypes without going through a molding/casting cycle every time; (2) more detail doesn't mean more work (or at least, not at the usual ratio); (3) you can incorporate fairly precise mechanical elements, including built-in, enclosed moving parts (like the button in these M40's, which acts like a separate piece with a spring below it, but is probably part of the main body); (4) automation and repeatability: once you've got a good model, you can print as many as you want without much manual effort.

I don't think any technique necessarily lacks soul; it's just a tool. The soul comes through the tool from the tool user. I haven't done any 3D printing myself, but I've got a desktop CNC router, which is like a 3D printer that prints holes instead of plastic. Using it well takes enough creative attention that I think there's room for a bit of soul to come through.

For myself, though, I do consider these workshop robots to be "cheating" compared to more traditional hands-on techniques, and I mostly prefer not to use them for prop replicas. Mostly.

But my main problem with 3D printing, filament printing at least, is not so philosophical. It's simply aesthetic. The stuff doesn't look, feel, or sound good. Usually when I pick up a 3D printed object I immediately want to put it down again. The surface texture is sort of gritty in a peculiar way, with the layer lines kind of scraping against everything. The objects look good (sometimes) from a distance; the form might be almost perfect at the macro level; but if you look closely everything is kind of low-resolution.

That just isn't how real objects look or feel. You can work to improve it, but at that point it's probably better to just use a different technique.

Paint, of course, is the great equalizer. You could prime, sand, and paint a marshmallow and it would look as much like metal as any other base material. Which is great visually, but it means that whenever you pick up a prop replica, all you ever feel is paint. It's better if you can let some real materials show. 3D printing is kind of the opposite of that.

Of course, in this project I was getting an even less convincing surface texture than that, so far. So despite these complaints, I'm accepting these 3D printed M40's as the best-looking ones in my collection for now. For what they are, they're great. But they'll never satisfy me completely.