Portable Motorized Turntable (from an Angle Grinder)

Inspired by the "Finish It Already" Speed Challenge, I picked up an old project that's been on/off for over a year I had planned for a previous contest.

The reason why I shelved the project is a silly one. I tried thread sizes to see what nut would fit the grinder head; no metric thread I grabbed worked. I figured it was imperial and just shelved it for a looooong while. Turns out it actually was a standard thread (an M14) but I wouldn't find out until I tried thread sizes again... 1 year later. Best guess is the M14 I thought I grabbed was an M13; This project could've been finished over a year ago if I had just double checked -_-

This Instructable is about making a simple and effective, portable turntable with adjustable speed that can set up anywhere with ease, for B-roll project/product shots and display purposes. The heart of this turntable is an angle grinder head. These are incredibly sturdy, threaded, can take a lot of abuse and houses a built in spindle gear. This was salvaged from a busted angle grinder I found in a skip and perfect for repurposing.

Step 1: Hardware

Requirements:

• An angle grinder, preferably an out of commision grinder (Mine is a Makita for reference), salvaged for its head and crown gear
• Standard nuts that fit your angle grinder head (this one is M14)
• a geared motor with a shaft that fits the crown gear (typically 6mm),
• a low voltage DC Motor controller,
• a power switch (mine was salvaged from a vacuum)
• MDF to build the frame,
• A WAGO clip (optional but handy)
• M3 - M5 bolts
• And material to mount the motor and head

Step 2: The Concept

To be sure my idea worked, I mocked up a plate made from pvc sheet to mount the grinder head and motor together. This was done by marking where the attaching points are for the motor and grinder head and threaded bolts through the pvc.

I hacked up a cardboard box to fit the switch, motor controller and power supply and hook it up to the plate to be sure the angle rinder head works. It works so well and with so much torque, I physically cannot stop the angle grinder head from turning, this means it can shift a whole lotta weight.

From this I mocked a model of the layout for reference.

Step 3: Box Construction

Note: Dimensions are based on the angle grinder head so measurements differ from other types of heads, the key is to build around the size and allow enough space for the head without interference.

Using my mockup 6mm mounting plate, I chopped it down to 9cm² and built around it. To make removal of the head unit easier for disassembly I cut grooves into my MDF to slot the plate in place. My base MDF was 8.1cm wide with 2 MDF sides making it 9.9cm wide total. 4.5mm slots were cut along the base and sides to fit the plate. All glue used for MDF in this product is superglue. The box's final length is 26.5cm.

To tighten up the tolerance of the plate slot, 12mm mounting blocks with 9mm clearance were added up against the face of the block and the back end, 4 points total. These are used as posts for lid screws.

The lid is made from the same 9mm MDF. the width is 8.1cm and runs along the length of the box. The lid sits on the mounting blocks flush and drilled and countersunk for bolts.

Step 4: Mounting Motor + Layout

The head mount is sturdy but the motor has no rest. Make a block with a radius that matches your motor out of a chunk of MDF. This helps relieve pressure on the mount should something very heavy be placed on the plate.

Drill and mount your DC controller and power switch to one side. Solder wire to your motor and attach the wires to the DC motor controller in the appropriate slots; these boards typically have markings showing where each wire goes. (Motor +, Motor -, Power + and Power -)

Note: If you don't have a soldering iron, feed wire through the motor contact holes, loop it and heat shrink for a solderless joint.

Connect the motor wires to Motor + and Motor - respectively, Feed one end of the power switch through Power + and ther other to the WAGO clip and finally, add the other wire to Power - and the WAGO clip. Your DC power supply connects to the WAGO clip (with this setup, red to positive, black to negative)

This motor and motor controller can handle between 4.5V to 15V, perfect for 4XAA batteries, 9V batteries and even 10.8V Drill batteries if you need power in a pinch, great for on site use where a drill is always around. The WAGO clip is especially great for this use as you can swap out wires by lifting the orange tabs.

Step 5: Turntable

The turntable bases are very simple. It's an MDF circle with a nut in the middle and an MDF cap to secure the nut. The disc can be any size depending on your application, I kept mine relatively small at around 15 inches, thought the size can go far larger if necessary.

Superglue a nut to the centre of the circle (in my case, M14) and wood glue a cap to secure it. a 25mm hole fits the nut tight. For an added measure of security, I filled the gap between the hexagon nut and the round hole with epoxy to be absolutely certain the nut would not come off.

These are so easy to make you can make a whole assortment of plates for different applications.

Step 6: Demo + Final Shots

Add just like that, a portable motorized turntable is made!

With this configuration, I can take it just about anywhere, power it with a simple DC supply, place multiple kilos of weight with no issues and control the speed to my liking; not bad for a little geared motor and scrapped angle grinder.

The GIFs really show off what it can do; that vice weighs at least 15 kilos and it handles it as smoothly as the little LEGO figure in the other GIF. It also shows how quick each plate can be removed and reattached.

The turntable can be mounted vertical too; perhaps a spinning dart board or an airsoft target can be made, It didn't occur to me originally how this could be repurposed. If you have suggestions I'm always happy to hear them.

P.s. As requested I've uploaded a video demoing the speed control of my setup. At 12V it maxes at 15RPM and can slow down to well under 1RPM; perfect for my needs. Speed/Torque is based on the motor and its gearbox so if you wanted more speed at the cost of torque, use a motor with less reduction. If you need more speed and more torque, you'll need a bigger motor. Voltage also plays a role, more volts = more input but motors have a limit so check what your motor can handle.