Rolling Stool - Free Plan

I always wanted one of those five-legged stools like the doctor scoots around on when he has you trapped in his little examination room.  So I built one, using some beetle kill pine from the rack at Home Depot and some swivel casters from Harbor Freight.  It looked like this:

I figured from the beginning that sitting on it would tend to pry the legs loose from the little hub-like piece near the bottom, so I was very careful to attach the legs firmly to the hub.  So far, so good.  So far, so good, that is, until one day the hub itself split in two as I sat down on the stool.  Oops.  Butt, meet floor!

Design attempt #2 worked out much better.  It looks like this:

With the legs transmitting the load directly from the seat to the wheels, it's not trying to rend itself asunder when you sit on it.  Better materials (hardwood and metal tubing) didn't hurt, either.

Free Plan

This PDF file contains detailed drawings for all of the stool's parts as I built them.  There's also a SketchUp model here.  I made all of the wooden parts from oak, and the metal parts from 1/2" thin-wall electrical conduit.  I glued up some 3/4" boards to get the required thickness for the wooden parts.  I also had to glue together a couple of pieces edgewise to get a board wide enough for the seat.

Here are some hints that might be useful if you want to make one of these for yourself:

The Metal Parts

The metal parts are all straight sections of 1/2" thin-wall electrical conduit, so just cut them to length according to the plans.  If you want to paint the conduit, now is a good time so the paint can dry while you make the wooden parts.

The Seat

After you've cut out the seat, you'll want to put a slight round-over on at least the top edge so it doesn't cut into your leg when you sit on the stool.  Also, you'll need to accurately mark the center of the bottom surface for reference later when installing the legs.

The Other Wooden Parts

The hub, the feet, and the connectors are all drilled to accept parts made from conduit.  These holes need to fit the conduit fairly closely.  Since you probably don't have a 0.705" drill in your toolbox, make one by carefully grinding down both sides of an old 3/4" spade bit until a test hole in a scrap of wood fits the conduit.  Aim for a snug fit.

After cutting out the hub and the feet, carefully lay out the locations of the holes, then use a V-block for support while drilling with the modified spade bit.  Be careful to stop when you reach the depth indicated on the plans.

For the connectors, lay out the holes as before, then use the connector drilling fixture shown in the plans to hold the connectors at the proper angle for drilling.

Assembly

Start by gluing five of the connectors to the five feet, as shown in the plans.  Each connector should be centered on the top surface of a foot, with the hole in the connector aligned with the middle hole in the foot.

Next, insert the five spokes into the hub, as shown here.  (Click on any of the images for a larger view.)  Make sure the spokes are fully seated within the holes in the hub, then drill pilot holes halfway through the bottom of the hub and into each spoke.  Install a 1" sheet metal screw into each hole to keep the spokes from twisting or coming out of the hub.

Now assemble the feet and braces together with the hub and spokes as shown.  This may be kind of tricky because it all has to happen at once.  Start by positioning the parts so that all the braces and spokes extend just a short distance into the holes in the feet.  Then work your way slowly around the assembly from one foot to another, gradually pushing the metal parts into the holes until they are all fully seated.

Next, turn the entire assembly upside down on a flat surface so that the feet are all in the same plane.  Check one more time to make sure the braces and spokes are all fully seated within the holes in the feet, and use clamps and/or weights as needed to force the connectors against the flat surface.  With everything in position, drill pilot holes and pin the spokes into the feet using sheet metal screws as before.  Important: Here, the heads of the screws must be sunk into the bottom surfaces of the feet so they don't interfere with the installation of the casters later.  You don't need to pin the braces.

In the next step, you will complete the assembly and glue the five remaining connectors to the bottom of the seat.  To make this easy, it's helpful to install some temporary guides on the seat to help position the connectors correctly.  Starting from the center point you marked earlier, draw five radial lines, 72 degrees apart, on the bottom of the seat, as shown here:

Next, draw five 3" x 1-1/2" rectangles to represent the footprints of the five connectors.  These rectangles should be centered on the five radial lines, and positioned 1/4" in from the edge of the seat.  Finally, use hot glue or small brads to temporarily attach small strips of wood along two edges of each rectangle, as shown.  The connectors will register against these strips in the next step.

Now insert the legs into the connectors on the feet and slip the remaining connectors onto the top ends of the legs as shown.  As always, make sure the metal parts are fully seated into their respective holes.  Apply glue to the seat and the connectors, align the connectors with the temporary guides, and clamp the connectors to the seat.  Once the clamps are in place, remove the temporary guides and wait for the glue to dry before removing the clamps.

Install some casters to the bottom of the feet, and you're done!