Holy crap, this miniature spear build was good. I have to be honest, I knew I could make something a bit tasty, but the end result was so good I couldn’t believe it. This is possibly the most fun I have had to date with a build for you guys on my channel, they are just so much fun to build and fire. You know the end result is good when even your mum says wow, just remember it’s not a toy.
How to make a miniature spear
First you only need a nail and bamboo barbecue skewer as raw materials, oh and some epoxy glue or similar to glue the spear head to the BBQ skewer. A bit of cotton thread and superglue is an option for reinforcing and aesthetics.
- Take a nail, I used two sizes, the smallest spear was made using a 3.5mm x 65mm lost head, whilst the other three were made from a 4.5mm x 100 round wire nail. Both nails were a good quality carbon steel, but I dont think it really matters.
- Once complete the smallest mini spear head was 17mm long and the other three ranged from 23-25mm in length.
- The holes drilled into the base of the spear were a 1.5mm pilot followed by a 2.5mm final finish. The hardest part was getting the pilot hole central. Patience is the key, especially when it’s all done without a pillar drill as I did.
- The length of the bamboo BBQ skewers were 70mm for the mini spear, and ranged between 120 to 130mm for the larger three. Make sure you pick a straight one. Getting the skewers to fit into the holes was very easy by using a metal file to remove excess wood.
- I found the easiest way to fix the skewers to the spear head was with epoxy resin, I was initially concerned this would be a weak point and came up with two methods of strengthening. First was cross drilling the base of the spear head with a 1.5mm drill to allow the epoxy to bleed through and allow extra grip. Secondly was the addition of cotton thread wrapped around the head of the spear and the bamboo shaft. Both of these methods worked, but as it turned out I did not have any problems with spear heads falling off anyway as long as the spear is removed from the target nearest to the head.
- It is very important to make sure the the spear head is upright from all angles whilst the epoxy dries to maintain accurate flight.
Mini spear launcher
Basically this is a catapult tube made from a pen, powered by a sturdy elastic band. At around 50mm in length it’s pretty much ideal for spears from 60 to 180mm long. For maximum power I found if I loaded the miniature spear as seen in the video, I could hit targets with a very good accuracy over 6 to 10 feet, and up to 60 feet away at a push. Shooting 20 to 30 feet was very do-able inside my lounge and considering the target is only 8″ in diameter, I’d say thats impressive. For lowering the power or for longer spears the launcher can also be turned around 180° so the elastic band is now slack and there is space between the band and launching tube. The cotton thread wrapped around the tip was the best way to ensure that the elastic band never became detached from the pen body, important when you shoot a lot as you do when developing a build.
Mini spear size and weight
What you never see in a 6 minute YouTube clip is the work that happens behind the scenes, and this is often the part I like best, although I understand it bores others. To achieve a good flight and distance you need to trade off the weight of the spear head, the balance and length of the spear’s shaft. Obviously we want a miniature spear to be as miniature as possible, so compromises will have to be made to achieve distance and accuracy. After a lot of messing about I found that for the nails used and the mass of the spear heads, the smallest I could get a decent spear was just under 90mm for my smallest and about 150mm for the larger versions. With the weight ranging from 1 to 2 grams respectively.
Mini spear aerodynamics
I was careful during the build to make sure that the spear heads were as symmetrical as possible. On occasion I had to shave slightly more from the BBQ skewers to create a loose fit, this then allowed me to adjust the head and pack it out with a little epoxy incase my drilling wasnt perfectly central or upright. By far the best shape for aerodynamics would have been a simple metal point, but these are just boring to look at. Maybe if I revisit this project for maximum power distance and penetration I would change the design. I have some ideas 😉
Barbeque skewer shaft
This was the simple and logical choice. The strongest lightest and cheapest material for the shaft is a bamboo BBQ skewer. The only other real contender was metal but the balance became all wrong and the spear massively unstable over any distance. I was concerned that bamboo wouldn’t hold up to being fired from the launcher and impacting a target, but this proved to be wrong. And as long as I pulled out the spear by the head near the tip, I had no problems at all.
The above project is aimed at adults for education and entertainment purposes only, not to replicate. Anyone doing so takes full responsibility for their own actions.