This is a fun and very useful tool for removing unwanted plants or small trees. By using very inexpensive components you can build your own wood cutter and I'm going to show you how!
**Warning** Can be very dangerous!
Step 1: How Does the Wood Cutter Work?
It's very simple! It's basically a motor swinging a sharp blade attached to a handle. The motor is regulated using a speed controller combined with small chip that converts the thumb throttle to a signal. This will all make sense later in the instruction!
With the lithium polymer battery and a low KV brushless motor this wooden cutter is very efficient and allows you to be out working for up to an hour. Certain brands of trimmers use a grip throttle that fatigues your hand, but with a thumb throttle you can comfortably and without effort control the speed of your brushless motor.
Step 2: Material
Here is the things you will need for the build:
- Plastic bottle
- Plastic lunch box
- 25mm wooden dowel
- ESC http://www.hobbyking.com/hobbyking/store/__24563__...
- Motor http://www.hobbyking.com/hobbyking/store/__14342__...
- Servo tester http://www.banggood.com/Servo-Tester-Third-Gear-Sw...
- Thumb throttle http://www.banggood.com/Universal-78inch-22mm-Hand...
- Battery http://www.hobbyking.com/hobbyking/store/__8932__T...
- Scrap material (foam, aluminium and wood)
Step 3: Motor Mount #1
The motor mount is made from a plastic bottle and a lunch box. This is very convenient as this is household items.
Begin with cutting the 2L plastic bottle 1/3 from the top, this will act as the motor protector. Use the bottle to draw a circle on the bottom of the lunch box and cut it out using a dremel or any tool of that nature.
Step 4: Motor Mount #2
Cut a piece of foam into a circular shape, the same diameter of the plastic bottle. Cut a hole big enough for the motor to be spinning without touching the foam walls. The foam washer will increase stiffness and make it easier to glue the motor in place.
Drill the necessary holes for the motor mount and secure the motor using screws with loctite. Glue the foam washer in place with the plastic motor mount flush against the bottle edges.
Step 5: Handle
Take a 1 meter long wooden dowel, preferably 25mm diameter, and cut on end at 45°. Unscrew the cap and glue it to the 45° cut (use plenty of glue!). Use electrical tape to reinforce the high stress point.
Connect the electric speed controller (ESC) and make sure the motor is spinning clockwise. Use electrical tape or heat shrink to make the ESC waterresistant.
Step 6: Throttle and Control
Remove the wrapping from the servo tester and desolder (or cut off) the dial shown in the first picture. Take a piece of wire and solder it according to the second picture. This will enable us to use a thumb throttle and will make RPM management easy. Connect the speed controller and thumb throttle to the servo tester and tie the cables down using cable ties.
Step 7: Blades
Take a look around your home, I'm sure you have some scrap metal around somewhere. The dimensions of the blades depends on the thickness of your material. However, here's the length, width and thickness I used:
- Length = 150mm
- Width = 30mm
- Thickness = 2mm
Make them as sharp as you possibly can! This is crucial for the wood cutter to work properly.
Step 8: Attachment
In order to attach the blades to the motor we have to make an adapter. Take a scrap piece of wood and drill holes for the blades and the motorshaft. Due to unbalanced blades we will have vibrations, so loctite is a MUST! Don't go easy on the loctite, use plenty! Same goes with the nut for the motor shaft (propeller adapter).
I think now is a good time to emphasises how dangerous this machine is. You will have two sharp metall blades spinning at high speed. Do NOT use it if you feel uncomfurtable!
Step 9: Shield
Use steel-wire and bend it to shape for a shield to hang just behind the spinning blades. This step is important to increase the safety of this machine. You should also wear eye protection and gumboots. The protective shield should be made from a non-brittle material, and remember to almost drag the shield against the ground while trimming as the blades, in case gets lose, will be thrown close to the ground.
Step 10: Start Cutting!
It's a very effective machine and with a large battery you could be out for hours! Since you only use the motor for a short period of time it's difficult to keep track of the voltage, so make sure you use a cell spy (voltage alarm). I use it to cut grass and smaller trees, but you can even use it to cut branches!
I hope you found my Instructable useful and inspiring, if you have any questions you can post them below. Want to see more DIY projects like this? Subscribe to my YouTube-channel here: https://www.youtube.com/user/RcLifeOnSimon