Sanding those curves while protyping, you will never have enough sanding tools to get the job done. So thats what this instructable is about, building a cordless drum sanding machine out of common hardware avliable.
This homemade cordless drum sanding machine offers a rotatory head that is attached with interchangable roller to offer multiple sanding grits. The tools has a variable speed control to offer percision sanding throughout a vast range of materials such as plywood, MDF, aluminium, acrylic etc.
The Drum sander is powered by a brushless motor coupled with a lithium ion battery pack.
So lets built it...
Step 1: Tools and Material
Step 2: Mounting the Motor
First of all we have decided to use brushless dc motor to power our drum sander, so we extracted the motor from an old 12V DC fan. We have cut down the whole casing of the fan. Then we have mounted the motor on the 5mm MDF sheet that we have cut down using table saw. After that we have cut down 3 inch PVC pipe and the glue it to the bottom side of the MDF sheet in order to place the battery and some electronics properly.
Step 3: Battery Pack
In order to power up our drum sander we have use three 18650 lithium ion cell that we have extracted from an old laptop battery. We have start soldering the cell in 1P 3S configuration and then we have added the battery management system BMS in order to protect the battery pack from over discharge.
Step 4: Adding the Button and Charging Jack
After making the battery pack we have sold the the toggle switch and mounted it on the PVC pipe. For recharging the battery pack we have used the 12v dc socket and soldered on the terminal of the battery pack.
Step 5: Customised PWM Speed Controller
For precision sanding across different materials we need to control the speed of the sanding head. To do so we are going to use a customized speed controller that we have design and built in one of our previous video.
I would love to thank JLCPCB for making this project possible by providing us great quality customized PCBs which made the controller a preety neat job. They are one of the largest PCB manufacturer in China providing a wide range of services for manufacturing customized Printed Circuit Boards throughout the globe.
JLCPCB Prototype for $2(Any Color): https://jlcpcb.com
For more details about the speed controller please visit the following links:
Schematic,Gerber files and Components list:
Step 6: Wiring Things Up
In order to control the speed of our dc motor we have used PWM speed controller that can control the speed of motor sufficiently. So we have attached the battery terminal wires at the input port and motor wires are connected at the output terminal of PWM controller. Then we mounted the speed controller on the PVC pipe in order to control the speed easily.
After completing all the wiring work we have glued the the battery pack to the base plate and then we have added four rubber pads at the corners of the base plate in order to reduce the vibration effect while working.
Step 7: Paint Job
In order to give the sander a nice look we have covered the pvc pipe and the motor using tape and then paint it using matt black spray paint. And then remove the tape after the paint get dry and the result were awesome.
Step 8: Making the Sanding Grid
After completing all the work, its time to make the sanding rollers so we have cut down the 1 1/2 inc diameter pvc pipe into 1 inch pieces that fits perfectly on the motor bell. So we glued sand paper on the roller using super glue.
We have use two different types of sand paper in order to make two different grids.
Step 9: Final Results
This little Drum Sanding Machine is indeed a nice addition to our ever growing DIY tools collection. With the efficiency of a brushless motor coupled with the power of those lithium ion cells this thing is a little beat packed with a punch.
With the capablity of getting across those curve shapes its definaltely a useful tool.
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