This instructible uses power tools and some techniques use them in ways they were not designed for, whatever you do is on your own this is just a guide on how I did it, I take no responsibility for what might happen.
Now that you have been properly warned lets go on....
Step 1: Making the Pulley
1.Cut a 2in circle from the MDF using a hole saw mounted in a drill press or a hand drill, you want the inside part that is being cut out so select a nice piece and cut it strait, if you are using normal wood make sure there is no knots in or around the piece you are cutting.
2.Get a hold of a bolt, some rubber bushings and two big flat washers, you will also need a nut that works with the bolt. It is a good idea to use a longer bolt this way you can mount it easily in the drill press.
3.Mount the circle you just cut out in step 1 on the bolt as shown in the picture below, don't screw it together too tight so that if it will kick back wile turning the piece will be able to slip between the rubber bushings. I had this happen to me a bunch of times and this helped a lot.
4.Put the whole assembly in your drill press and lift up the table so that the head of the bolt is in the little through hole in the table, this will prevent it from swinging sideways and with the table this high up it is easier to rest your hands on it while holding the cutting tool.
5.Cut either a V or U groove in the side and wile still spinning wrap a piece of sand paper around a round object (screwdriver) and sand the inside of the groove.
Congratulations you just made the pulley! There is also a great instructable on how to use a drill press as a lathe right here: https://www.instructables.com/id/Woodturning-with-a-drill-press/
Step 2: Cutting the Bracket
1.Draw out a template for your cuts on a piece of sheet steel, and mark where the mounting holes will be. (The drawing I attached is not to scale so do not use it as a template, it is just there for dimensions)
2.Cut it out any way you like to, I cut mine using an angle grinder while the work was positioned in a vice.
3.Score the two fold lines with an angle grinder or a dremel to make the folding easier.
4.It is a lot easier to drill the mounting holes while the piece is unfolded so I advise you do it in this step.
-First, put a punch mark where each hole is suppose to be.
-Drill both holes using a drill bit appropriate to the size of your mounting screws.
-Since I'm going to be using wood screws I decided to also counter sink the holes so the screws will sit better. If you don't have a cutter that can do something like that you can just use a bigger drill bit.
5.I also deburred the cut out piece on a bench grinder and added little fillets on the corner that will stick out.
Step 3: Folding the Bracket.
1.Place the plate in a vice so the jaws grip it right on the fold. This way when you fold it and then hammer it to get the bend right it will fold right on the line that you scored.
2.Fold the part that sticks out and hammer the crease onto the vice this way it will be somewhat square.
3.Repeat this for the other side. It is a little tricky to secure it in the vice once one side is folded to just stick some thick plate or a piece of wood between one of the jaws so it wont bend the fold you just made when you tighten the assembly.
Unfortunately I didn't take any pictures of this step but it is pretty strait forward, remember to fold it the correct way if you counter sunk your mounting holes.
Step 4: Mounting the Pulley in the Bracket.
1.Mark a point that is in the middle of the part that sticks up and roughly .5in from the top edge.
2.Select an appropriate size drill bit that will work with your pulley, you can always use a bigger one and just drill they center hole on the pulley to make it bigger.
3.While drilling this through hole you want it to be lined up perfectly so you can fit the screw through. If the part that stick up is bending under the bit then place a piece of scrap wood in between the two and remove it to drill the one that is below.
Now just bolt the whole thing together and you are done! Tighten the bolt so that the pulley can still spin and apply a little locktite on the threads, if your painting the hold off on the locktite till final assembly. If everything fits good then you can also paint the bracket to protect it from rust, after all you didn't do all this work for it to rust away after a couple of weeks depending on where it will be used.