Introduction: Folding Wooden Stepladder
I made this wooden stepladder based on some plans I found online.
I didn't follow the plans very closely (my bolts and dimensions were different) - I just used the general layout of the stepladder as a guide.
This was the first project I've made using a tablesaw. You could make this stepladder with a circular saw or even a handsaw, but I found the tablesaw made precision cuts really easy.
In this instructable I also describe how to use a router to make dado joints and consistent curved corners.
Step 1: Materials
You'll need a sufficient quantity of reasonable quality wood - I used about 7 planks of white pine, measuring 90 x 20 x 900 mm
8 x M8 carriage bolts, about 55 mm long
8 x M8 washers
8 x M8 lock washers
I used carriage bolts which have a large dome head, this means you only need a washer on the end with the nut.
The lock washers are needed because the bolt are inside a moving joint. Without the lock washers the nuts would gradually undo themselves.
M6 bolts would have worked fine too.
Step 2: Tools
Tools I used in this project:
Drill press (the bolts really need straight, 90 degree holes)
Router (not essential)
Jigsaw (not essential)
Sandpaper - I used grits 180 and 320.
Eye protection (essential)
This project uses several power tools. Respect these tools, never take shortcuts. Safety First. Remember hearing and eye protection.
Step 3: Overview
The stepladder consists of four different assemblies:
- Back support: Two sides with three joining pieces (stretchers). Joined by dowel-reinforced butt joints
- The steps: Two sides with three steps. Joined by dado joints.
- The top: Five slats with two supports. Joined by dado joints.
- Side supports: Two simple side pieces with rounded ends.
The stepladder folds up to form a compact unit for storage.
Step 4: Inital Cutting
First I cut the pieces that would form the legs to size with a 60 degree angle on each end. Running the legs through the tablesaw clamped together ensures that they are the same length.
Next I ripped several boards in half. I used a piece of scrap to check that my fence was set at the right distance from the blade.
I cut the ripped pieces to length (various parts) and put an angle on the top supports (my first deviation from the plan).
Step 5: Top Piece
In the plans, the top slats are joined onto the supports with dowels. I decided to use a dado joint instead.
I used a router to cut these dados.
I didn't line up the slats perfectly with each other while I cut the joints (oops), so after the top was glued up I used the router again to trim their ends straight and flush.
Step 6: Rounding Template
Because there are several rounded ends on this project, I made a rounding template to make identical rounded corners quickly and easily.
The template is made out of a scrap piece of MDF. First I cut it to the right width. Then I drew a half-circle of the right diameter on it.
I rough-cut this half-circle using my electric jigsaw, then filed it closer and closer to the line with a rasp and a file. Sandpaper gives the template a very smooth profile.
It is worth spending a bit of time at this stage to make sure the template is very accurate, since you will be using it on several parts of the project. If it is wonky, the wonkiness will be copied to all the curves on the project!
Using the template is easy. With a flush trim bit in the router, I clamped the wooden piece to the template and ran the bit around gently, then more firmly, to form the curve.
It's an easy, repeatable cut, just needs a bit of cleaning up with sandpaper due to the way the curve cuts into endgrain.
I rounded both ends of the step supports, the top of the back supports, and the side supports.
For each piece, I cut curves on one side and used that side as a template for the opposing piece - this makes sure each pair of pieces are identical.
Step 7: Steps
The plans show a stepladder with two steps. I decided to put three steps on my stepladder. After figuring out the spacing of the steps, I drew their positions on the step supports.
I cut the six dado joints in the step supports, which I cut using my router.
These are the nicest joints I have ever made, they were a very tight fit even without the glue. I like making things 'properly' - without any screws or nails - I think I will try to use more joints like these.
I cut the three steps to length and made sure they were identical. I also made sure there were no large knots in these pieces of wood. We don't want a step breaking due to weakness introduced by knots.
There was a bit of tearout at the edges of the joints, will have to try harder to avoid this in future - maybe use a bit of scrap at the edge to try and prevent this.
Step 8: Back Support
You can see the parts which make up the back support. In the plans the stretchers between the back supports are placed on top and fastened with through-dowels.
I made my stretchers fit between the back supports instead, and used blind dowel joints. I think this is more attractive and it is very strong and sturdy.
I made a simple jig with a piece of scrap to make lining up the dowel holes easy.
Step 9: Adjust Folding Action, Drill Holes
At this stage I spent some time dry-fitting the pieces to check that everything would work properly. I trimmed the back stretchers to length and put a angle at the end.
I hadn't made anything which folded up this way before, so I used some scrap pieces of wood to demonstrate to myself how the folding mechanism would work. The legs and supports basically form a diamond which folds to bring the two sides flat together (in theory!)
In reality, the back support did not want to fold fully flat against the steps. D'oh!
After a lot of experimenting and thinking I improved the not-folding-properly situation by cutting the tops of the back stretchers at a slight angle, using a simple jig on the tablesaw.
This angle improves the folding but doesn't fix things totally.
I think the correct way to fix this would be to drill the bolt hole in the back stretchers quite a lot closer to the edge of the wood.
Once I was satisfied I had done all I could to fix the folding problem, I drilled the bolt holes. All the holes were drilled in my drill press with pairs of parts clamped together, so the holes would be aligned correctly.
Step 10: Sand
At this stage I sanded all the pieces with 180 grit sandpaper to clean up the surface and remove pencil marks.
I also ran sandpaper along all of the edges to round them off.
I like to make my projects as accurate, strong, well-made and nicely finished as possible, to push myself to develop my woodworking skills. Although the stepladder will have a utilitarian purpose, that doesn't mean it can't look good.
Step 11: Glue Up
Next I glued up the various assemblies to form solid units.
Clamping the back support was quite awkward and it came out slightly warped, but this doesn't seem to matter much in the final product.
I glued the top slats onto the supports two at a time, spacing the slats with a scrap piece of plywood so they were all evenly spaced apart.
Step 12: Test Fit and Adjustment
With all the pieces glued up to form strong pieces, I put the stepladder together to check that everything was kosher.
I found that the stepladder didn't lock firmly into a level position when open. The plans I was using had a piece of wood at the top of the steps which sits firmly against the top when open, which I left out in favour of a third step.
You could fix this problem in a number of ways, I simply found some small bolts with large heads and screwed them into the top of the step supports, these sit solidly against the top when the stepladder is in the open position.
Step 13: Finishing
I finished all the pieces with three coats of thinned polyurethane (50% polyurethane, 50% turps). You can buy commercial wipe-on polyurethane, but it is easy to make yourself from standard polyurethane.
The thinned polyurethane was easy to apply and I had no trouble with brush-marks. You do need to be alert for runs and drips though.
I sanded lightly between coats with 320 grit sandpaper. I also took the time to sand out any drips/runs.
Finishing can be the most boring part of a project, but doing a good job at this step can make a big difference to the finished product.
To speed things up, I:
- Wore an old coat to protect my clothes (no need to put on old clothes for each coat)
- Wore disposable gloves (no need to wash polyurethane off hands)
- Used cheap, throwaway foam brushes (no brushes to clean)
Step 14: Final Assembly
When the final coat is totally dry (you don't want the moving parts to stick together) you can put the stepladder together. I rubbed some candle wax on the moving parts where the wood rubs together.
Don't forget the washers and lock washers at this point - without lock washers, the nuts will undo themselves over time as you open and close the stepladder.
Step 15: Final Thoughts
The stepladder works well as a stepladder (who would have guessed!).
If I was going to build this project again, I would see if I could make deeper steps. I was limited by the quantity of wood I had on hand. It works fine with the shallow steps, but deeper steps would be nice.
Now that the stepladder is done, I can see it would have worked fine with two steps instead of three. Not a big deal though.
A slightly wider stepladder would be nice too, it would be that much more stable.
Getting the stepladder to fold flat properly would have been nice. Following the plan more closely would have fixed that. Alternatively, you could make a full-size or scale model of the folding joint using scrap, to make sure that the folding parts will sit together properly when closed.
I think you could build a reasonably tall ladder using a similar layout, but you would want to angle the legs outwards, and then you would need to use something other than dado joints for the steps.
I am quite keen to make more projects with moving parts like this, it is neat being able to change the size of the stepladder for storage. Maybe you could make a fold-out toolbox ... or a transforming coffee table ... the possibilities are endless. :-)