The object is made of an upholstered metal frame resting on heavy-duty plywood rocking legs. It contains a pressure sensitive switch in the seat, which when activated, starts up a vibrating motor. Unplugged, it is suitable for children.
I tend to do only high level planning and then work out the details as I go along, so I have very few design notes and I ended up changing it up a fair amount when I encountered fabrication constraints. The notes are here, though, in case you are interested in my minimal design process.
After making this one, I made two more, in different mustache styles. I used the same basic technique so I didn't take any in progress pictures, but I include some finished pictures. The second is a blond walrus mustache style, which I associate strongly with the 70's so I tried to make the legs kind of 70's blobby/colorful. The final one is a Fu Manchu style, with a Chinese red set of legs.
Step 1: Saddle frame overview
- about 8 feet of 1" square stock of mild steel
- 18 springs reclaimed from an abandoned mattress
- about 10 feet of coiled wire spring from the same mattress
- oxy-acetylene torch
- MIG welder
- angle grinder
- soap stone or chalk
- grinding wheel
- welding table (not essential but it helped)
- metal chopsaw (angle grinder can be used instead)
I drew a picture of half of the top-down view of the frame (including spring layout), and half of the side view (without springs). I drew some guide lines as well to help me keep track of what curves went where.
Step 2: Saddle frame base
I clamped the square stock to the table and marked the center and the bend points, or more accurately the range of the bends. I used the oxy-acetylene torch to heat up the metal to red hot at the bend points, and when I thought it was ready, I held the end sticking off the table (yes with the welding gloves on) and leaned on it. I was almost surprised at how well this worked. I did have a little difficulty figuring out how to clamp the piece down, after I'd done some of the bends and there was no longer a long straight end to use.
For the more gentle bends, I simply heated a wider section of the square tubing, and did the same leaning. Again this worked surprisingly well; the metal bent quite evenly over the whole range of the heated portion. Because I was not using a jig, I did have to un-bend the second curve a bit to match the first. As I made the bends, I traced the actual shape onto the table as a reference for the second identical bend on the other end.
Step 3: Saddle frame struts
I pretty much eyeballed the shape I wanted, and it came out close enough to 45 degrees that I just used that. Since I wanted the final angle to be 45, I had to cut each side of the planned weld to 22.5 degrees. I had two pieces of about 2 feet each, so I marked the center of the shorter one and a corresponding length on the other, decided how long the outside of the new center segment would be, and marked that. I made five cuts altogether: four at 22.5 degrees for the angles, and one more to bring the final leg down to match the others. I could have done this with the angle grinder but I had access to a metal chopsaw so I used that.
I laid the pieces out on my 45 degree drawing, made them fit well enough (even with the chopsaw's angled clamp I did not end up with precise cuts), and tack welded them. Once all the tacks were done and the pieces were sufficiently matching, I finished welding all around the angle. I am not very skilled at welding and they were awfully lumpy so I ground them down some, but didn't bother making them too nice because this is still all going to be inside and invisible.
The final job on the struts was to attach them to the center support. Due to the curve of the center support, the struts needed to go on at a slight angle, to match the downward curve as much as possible. I again just eyeballed this, marked the lines I thought I'd need to cut on, and cut, this time with the angle grinder as the angle was too complicated for the chopsaw. The cuts were super ugly and didn't fit well, and I had to do a lot of remarking, trimming, and then grinding to get them to fit well enough. Then I tack welded them, holding each piece in place by hand, and did the final welds once they were tacked in place.
Step 4: Saddle springs
The springs came bound together with a different kind of spring, a long spiral spring, which was wound around two of the big springs at a time, to keep them together sideways. The tops of the springs had a spiral, and the bottoms as well. And since the spiral ran the width of the mattress, it also held the springs together crosswise. The sideways join was quite tight, but crosswise there was 3/4" or so separating each spring. I chose to retain some of these joining springs, but repositioned them on the bottom in order to give the whole assembly a curve to match the shape of the frame.
Once I had all the springs arranged to my satisfaction, I welded them on. This was an annoying welding job as the MIG welder simply didn't go low power enough to weld wire easily, and I kept breaking the springs, but eventually I managed it. In retrospect I should have used the torch for these welds, but the MIG is so much faster! I tested the springs with my hand, found a couple places where pressure made the spring bottom tap against the frame, and welded those so as not to have it make internal tapping noises when sat on.
Finally, to give a nice clean edge for the upcoming upholstery, I threaded some of the spiral wires along the edges of the springs and up to the mustache points, where I welded them down. My springs were not quite even but instead of repositioning and rewelding, I just hacked the spiral springs -- see the pic for that.
Step 5: Saddle finishing
The last remaining frame task was to create brackets onto which the legs will bolt. I bought a little bit of 90 degree steel with holes in it, and cut four pieces from it. I welded these pieces to the struts, which are nicely angled to give the legs some spread. In order to make sure the brackets on each side were aligned properly, I clamped a straight edge (my wire brush) to the first one when it was tacked, to tack the second. (In retrospect it would have been easier to buy a longer piece and only cut it in two.)
Finally I ground down the welds to the level of the brackets, so the legs would be able to sit flush against the frame.
Step 6: Legs
I drew a pattern of one half of the leg pair -- since I included the rocker, I needed the pair of legs on each side to be one single piece. I traced this pattern onto my plywood, and laid it out a second time where I just marked the approximate area it would take, so that I could cut them apart and attach them in a pile and only do the real cut once. I had intended to make a decorative hole where each leg met the rocker, but then I couldn't think of a good way to cut out the hole so I dropped it.
I cut the plywood into two chunks, then screwed them together and used a combination of a bandsaw, a scroll saw, and jigsaw to cut the edges. They were curvy enough, and the whole thing big enough, that I had a lot of difficulty and had to go from machine to machine, and ended up using a sander for some of the final shaping. (On the first set of legs I spackled and painted, but the second set with the expensive plywood was quite pretty as is.)
To attach the legs to the frame, I used machine bolts and locking nuts (the kind with a plastic insert). With the help of my friend Xander, who held the legs in place, I traced the locations of the bracket holes onto the plywood, then drilled them out. We then bolted them on and set the thing upright to measure for the braces.
I don't have any pictures of the fabrication of the 2x4 braces, but the construction was simply, eyeball the leg angle and cut with a circular saw. I was in a hurry, and they are a little uneven and of slightly different lengths (and therefore sit at different heights between the legs), but they are sufficiently strong. There are two per leg, one near the top and one near the bottom. They are screwed in with 1-1/2" #10 wood screws through the side of the legs.
Step 7: Vibrating motor
So I also rescued an old phone or other device transformer from Noisebridge's extensive scrap electronics pile. It is was rated for 5V and up to .7A, which is about perfect. When choosing a power supply, you want to use the least power that gets you the results you need, so while I found the motor would run on 24V as well, it wasn't significantly stronger of a vibration than at the 5V level so why spend the power? It would just get wasted as heat, and as it turns out, this motor can run almost indefinitely without getting warm. With the motor and the transformer, I only needed to add a pressure sensitive switch (see my other instructable referenced above).
I cut off the phone jack end of the transformer cord, stripped the wire, and soldered one of the internal wires to one of the battery terminals - the motor is not polarized, so it doesn't matter which wire went where (I didn't care which direction it rotated in). I added long wires to the other terminal cord wire and to the other motor terminal, to lead to the switch so it could sit on top of the saddle while the motor was attached underneath. After this soldering, I put a big glob of hot glue over the whole area for insulation and strain relief. The switch is a small square of felt with two conductive fabric tabs. I bent and soldered the ends of the switch wires into loops, folded the conductive tabs over a loop, and sewed them tightly by hand. I could use ordinary thread for this rather than conductive, as the thread simply held the two conductive materials together tightly and did not need to conduct anything itself.
To attach the motor underneath, I fabricated and constructed two brackets and welded them to the center bar of the frame (see pics and notes). I then just screwed the motor on using a couple machine screws. And then I took it off again until the construction was nearly complete, since the wires totally got in the way.
Step 8: Upholstery overview
- pens of different colors
- sewing machine
- hand needle
- about 2 yards muslin for the base pattern and the inner cover
- about 20 square feet of 2" open cell foam
- foam glue
- 1-3/8 yard canvas for the foam cover
- 1-3/8 yard fake fur for the outer cover
- 2 24" zippers for the foam cover
- 2 24" zippers for the fur cover
Step 9: Upholstery - inner cover
I was able to sew part of one under-point seam on the machine, but mostly I had to sew this by hand while the cover was in place. It could not be put on if too many of the seams were complete, like a really tight dress :) I just folded and pinned the fabric at the tips and hand-sewed that too; it doesn't really matter how they go together as there's only the one cover and it is underneath so much other stuff!
The only remaining issue was keeping the cover taut across the center bottom, as I could not cover up the middle frame where the motor would go (in the pics I have not yet welded the motor brackets but I knew they'd be needed). I solved this by just folding the fabric and shoving it under that one bar, and pinning with a big T-pin. It was REALLY awkward to try and sew in there and the pin ought to be sufficient.
Step 10: Upholstery - foam
- top bigger in all directions by 2"
- sides bigger at slanted ends by 1"
- sides extended at points by 2"
- sides lower than frame edge by 1/2" (but don't add foam to wrap the bottom)
My plan was to glue the foam together and then trim as needed. To glue the foam, I had tried a couple of tests of various kinds of glues I had around, but none worked well so I bought specialty foam glue from an upholstery shop. It was spray glue, so after I cut the foam pieces, I masked the areas I did not want to glue with masking tape to protect from overspray. I sprayed all the pieces appropriately, waited a bit for the solvent to evaporate, per the directions. Then I pressed the pieces together, which was quite hard to do given the complex curves involved. An assistant would have been really useful but I didn't think of asking anyone. I ended up gluing one of the sides on backwards without realizing it, but again it ended up being really forgiving and the final result was entirely satisfactory. I also should have worn gloves during the gluing; I had sticky hands for quite some time and no solvent to clean up (nail polish remover helped some).
Step 11: Upholstery - outer covers
First I created a paper pattern, as there would be more than one -- and I may make additional fur covers as well, if I get tired of brunet I could go blond! I wanted this cover to be quite tight, to hold the foam in place as it is not otherwise attached, so I did not include any seam allowance except for at the zipper location. Due to the inaccuracies introduced in the foam layer, I also didn't make two separate patterns for the sides, but assumed they were symmetrical enough to fit the same pattern.
I made the following adjustments to the original pattern, to come up with one that would fit around the foam.
- top bigger all around by 2", grading to 1" at the tips per the trimming I did to the foam
- each side, 2" bigger at the top
- each side, 1" bigger at the slanted ends, plus another 1" seam allowance for zipper installation
- each side, darts at the mustache points above the zipper
- each side, added underneath material plus 1" zipper seam allowance
After cutting these pieces out of my cover fabric, a lightweight canvas that I had lying around looking a bit like mattress ticking, I laid the sides out on top of the foam and realized they were too short! Somehow I had missed some additional length increase. I'm still not sure where this came from, but the pieces were definitely about 2" shorter than the foam, which was too much to squish. I altered the pattern, and also had to add fabric to the cut pieces (see pics and notes) as I hadn't checked the fit of the pattern first, which was silly of me.
After fixing this I sewed the darts and inserted the zippers using a standard centered zipper installation technique of folding back the 1" seam allowance I'd left, and topstitching along the zipper tape far enough away that the zipper pull could still pass by. At the ends of the zipper I added a loop of seam binding, and a button, to prevent the zippers from coming un-zipped as the mustache is ridden. In the sections where the legs are, I put elastic into the seam to keep them taut.
Step 12: Finishing
Step 13: What to do with the thing?
If you have any ideas as to what to do with these things now that I've made them, please leave me a comment!