Introduction: Demonstration Turbine Stand
This is a simple stand for a wind turbine (or windmill) to use as a demonstration model in a classroom environment. I built it using nothing more than hand-tools and a 2.4m beam of softwood from the local DIY merchants.
I've been working with EWB-UK recently and this is the culmination of the attempt to design and document a simple turbine stand for use in the "Power for the World" workshop that is run in schools. The children design and build a turbine from simple materials to lift a weight a set distance the fastest, using a limited stock of resources
Step 1: Materials + Tools
- 2.4m x 33mm x 44mm softwood plank
- 6 x Corner Brackets
- 20 x Wood Screws
- Set Square
- 3mm Drill bit
- Sandpaper (to clean up edges)
Step 2: Dimensions and Measuring Out
We need to cut the 2.4m plank down into the individual pieces needed to build up the frame. These are:
- 3x 30cm pieces
- 1x 50cm piece
- 1x 100cm piece
Measure down the side of the plank and mark off the points as shown in the diagram. The smaller centre-line marks are for positioning later, so don't forget them. There's one each at the mid-point of the 30cm pieces and one on each end of the 50cm plank.
Using the set-square, draw horizontal lines for across all of the pieces to aid in cutting down later.
One of the 30cm pieces will be our vertical brace, so will need to have both ends cut to 45° angles to allow it to be mounted correctly.
I don't have a workshop, so I was using hand-tools to make all of my cuts. To make it easier on myself later, I made sure that I'd marked off the dimensions on the 3 "visible" sides (top, left and right) so that I could line my saw up with the grooves once I began cutting.
Step 3: Cut Out
If you have access to one, use a mitre saw to give clean vertical cuts
If (like me) you don't have a workshop, then things are going to be a bit more wonky. Not to worry, as we can use a couple of tricks to ensure out cuts are straight(ish).
I began by cutting pilot grooves along the sides I'd marked the dimensions onto. This allowed my saw to fall into the slots as I cut, keeping it roughly straight and true. Take it slow, and check the sides to make sure that you're still on target. If you can get someone to help you brace the wood while you cut, this step is a lot easier!
Once all the pieces are cut out, you may like to clean the edges of your cuts up with a little sandpaper to stop them being so rough. It's not vital, but it gives a much better finish to the stand.
Step 4: Marking Out the Base
Now we can start building up our structure
Start by laying out the base pieces in the H configuration shown in the images. This is where your guide marking is very handy. Line the pieces up on the table to get an idea of what you're aiming to complete, ensuring that your guide marking line up on all pieces. Image two show where the two 30cm pieces have been marked at the 15cm point.
After laying out the H, take a couple of the corner brackets (I used Blocks) and mark out using a pencil where they come to on the wood when they're in position.
Some of these images won't make much chronological sense as in my excitement I forgot to take as many pictures as I could have done!
Step 5: Drill Pilot Holes
Now that we know where the corner blocks are going to be positioned, it's time to mark out where the screws are going to be going.
It's important with the corner blocks that there are 2 different ways in which the block can be positioned. Make sure that you don't have the screws crossing inside the wood, as this can cause issues with longer screws (see the first image on the next step to see what I mean by different positions).
By lining the block up with the guidelines and pushing a screw into each hole, you leave a small impression in the wood that can be used as a guideline. If you want to be a bit more cautious, then use the lead of a mechanical pencil to mark out where to drill the holes.
I used a 3mm bit and a hand drill to make a hole deep enough for the screw to sit snuggly inside the corner block after it's been screwed down.
I'd recommend beginning with drilling and mounting onto the 30cm pieces. By having these pieces in place, you can "vice" the 50cm piece into place to mark where to drill the next pilots.
Step 6: Assemble the End Pieces
Now we have pilot holes in (at least) the 30cm sections, it's time to start the assembly process.
Screw the block with two screws into place. Loosely screwing in the single screw allows the second block to spin slightly so that you can slide the 50cm piece into place.
Position the 50cm piece so that all the guidelines match up correctly and firm up the loose screw to hold it in place. Following the advice of the last step, use the screw to mark out the pilot holes. You should only have to lightly unscrew one side of the vice to release the piece to be drilled though.
Once sorted out, get it back in there and screw your sections together.
Step 7: Attach the Upright
Mark out the centre point of the 50cm base and the centre point of the 100cm upright.
Line these marks up and repeat the previous steps for setting the corner pieces in place.
This gives you a stand, but it has little resilience to being knocked by a presenter with little patience stood in front of an audience of 40/50 14 year-olds
To help to brace against any kind of knocks, we're going to be adding in the final 30cm piece as a cross brace for the base.
Step 8: Crossbar
I found this step to be rather challenging with just my hands, so I grabbed my partner and asked her to kindly act as a clamp for drilling the pilot holes.
This step is all around making sure that the angle is as close to 45° as you can make it visually, with not too much importance on accuracy for this step beyond aesthetics.
I lined up my set square alongside the base and moved the cross piece around until it looked "about right". My partner then held onto the piece while I drilled the pilot holes through the cross bar and into the wood as close to 90° as I could manage.
After the first screw is set in the wood (I did the upper more difficult one first), your wood should be stable enough to be drilled into without assistance. Once the final screw is in place, you're finished. Pat yourself on the back and grab a beer (or alternative cold beverage)...you did it!
Step 9: Drill a Hole in It!
For our purposes, we needed to drill a hole through the stand in order to run a pencil through as an axis for the blades to turn on.
I took the 100cm upright back off the stand, unscrewing the crossbar and the two single screws in the blocks to release.
Starting at a small diameter, I cut a pilot to keep my hole as true through the wood as I could. I ran into a couple of issues with the size of my chuck in the drill not being able to accommodate a bit wide enough to make a hole for the HB pencil.
Once you get through with a wide enough bore, you can run a strip of sandpaper through the hole to clean up the edges and give it a good finish.
Step 10: Summary and Final Thoughts
This project was more than achievable in under 3 hours with handtools, so will be a doddle with powertools in under your belt.
Making it from a single piece of timber was important for me to minimise wasted costs to the project and get the best value for money. Ideally I'd have made the upright longer than 100cm for our activity, but I think that with some clever positioning of tables/chairs this is easy to overcome.
I feel that the corner blocks can look a little unsightly, especially with the dark blocks and light wood. To overcome this, I'd use metal angle brackets, but again this comes down to costs for the project.
The use of a pencil for the axle in our turbine can lead to the blades of the turbine hitting the upright if they aren't carefully crafted. I'll be gluing a doweling of about 30cm length into the hole that I've made for the pencil to stick out far enough that the blades don't impact on the frame.