First of all, I need to make a disclaimer here. I am not responsible for any harms and damages due to the information that is provided here. This post is purely for an idea or an inspiration for those who are interested in a simple DIY project.
The following basic tools will be required for building this machine. A sheet metal snip. This tool will make life easier on cutting the steel hanger strap. A screw driver. A screw driver will be handy for screwing self-drill screws on wood blocks and any other tightening needs. Allen wrenches. This tool will be used for tightening the helical beam coupling and shaft collars on a stainless steel shaft that will be discussed later. A file. You will need a file to sharpen one end of a stainless steel shaft to make a skewer.
The following materials will be needed for building this machine:
Galvanized Steel Hanger Strap, 3/4″ x 10′ coil, 28 gauge, Home Depot, qty of 1
M6 metric screw, Home Depot, qty of 3
Wood blocks, you may get them from Lowes or Home Depot but I am not going to specify sizes as there are many ways to build the structure to hold this motor.
Felt Pads, 1/2″ x 2-5/8″, Lowes, qty of 1 package.
#8 Flat Head Sheet-metal Screws, self-drill, Home Depot
Hose Clamps, for 1/4″ pipe (hose), www.mcmaster.com, part number 9434T17, qty of 1 package
Helical Beam Coupling, metric to inch (10mm to 3/8″) clamp-on style aluminum, www.mcmaster.com, part number 2464k6, qty of 1
Steel shaft Collars, 3/8″ ID, www.mcmaster.com, part number 6432K14, qty of 2
Stainless Steel Shaft with a Flat (D Shaft), 3/8″ diameter by 36″ length, www.mcmaster.com, part number 8632T158, qty of 1
12vdc Variable Speed Motor, gear motor with speed controller, Wondermotor, part number PN00409, qty of 1
Here’s how you are going to build the machine with the mentioned materials. Use the wood blocks with perhaps some metal braces to build a structure that holds the gear motor similar to what is shown on the following picture. I do not give details on this particular platform as I realize that there are much better ways to build a platform than this one. So I will leave it to your creative minds out there.
This platform involves hanger straps to hold the motor based on the three threaded holes on the motor. Cut the hanger straps to the right lengths. Simply use three M6 screws to secure the motor with the hanger straps. The other ends of the straps are fixed to the wood blocks as shown on the picture by using some self-drill #8 flat head screws. I also introduced an additional strap around the motor section to secure better. Stick a felt pad on the front end of the structure as shown on the picture. The felt pad will function as a bearing/support for one end of the skewer.
Now we should build a bearing/support for the other end the skewer. The structure I built is basically two pieces of wood blocks that sandwich a hose clamp, and on the U section of the clamp, I cut a section of a felt pad and stick it in there so now I have a bearing system. Be sure to make a good measurement to check the two bearing supports (motor platform bearing and the hose clamp bearing) are level. Here’s how the structure looks like. Again, there are many other ways to do this so don’t restrict your mind with this design.
Now let’s work on the skewer. It is surprisingly easy to make. Slide the helical beam coupling to one end of the stainless steel D shaft. Make sure the coupling is half way on the D shaft so to have enough room to fit the other half of the coupling on the motor’s shaft. I also introduced a shaft collar so it defines where the coupling should be positioned. There is another shaft collar some distance away from the shaft collar next to the coupling. That shaft collar defines where the meat would reach to the end of the skewer. The setup should look like this.
Now file the opposite end of the D shaft so it becomes a sharp point.
The overall look of the skewer should look like this
OK, you are pretty much done. All you have to do here is to pile up some bricks to set up your BBQ system. It would probably look something like this:
But I have a feeling you can do a much better job than I did on masonry.
Here is something I have discovered with the rotational speed of this system. Turn the speed to the slowest so the heat can penetrate better through the meat. Eventually, you will get to a point that the meat starts to drip fat that causes flare. Simply turn the motor to a higher speed and the meat will stop dripping fat but instead the fat is coating around the meat. It’s a pretty neat and useful effect.
Here’s a video on how this system is running.