Magnetic Shop Sweeper From an Electric Motor

I saw a magnetic sweeper used to pick up ferrous bits and pieces from your shop floor a couple of months ago. I thought this was pretty cool, and then I looked at the price tag and decided it wasn't that cool after all. Shortly after that my shredder crapped out so I ripped it apart and one of the things I was left with was the magnets in the motor housing. I had a bright idea to build my own magnetic shop sweeper, but no motivation until this contest came up. So this is how I built a magnetic shop sweeper out of stuff I had accumulated in my parts collection. I had to buy one part. So the reuse aspect and fact I didn't buy something that had to be transported halfway around the world from where it was made, makes this project green. Plus you can recycle all the little bits you pick up.

This is a list of materials I used. This is meant to be a guide not an exclusive list as everyone will have a different parts hoard.

• 1 motor housing (or other big honkin' magnet)
• 2 Castors or wheels of some sort
• Metal rod (or a suitable alternative to serve as an axle) Mine happened to have threaded holes for screws in it.
• 4 screws w/ nuts
• 1 ¾" dowel rod
• 2 pieces of scrap metal
• Metal bonding epoxy
• General use epoxy
• 2 Plastic buttons from an electronic device (or other suitable material to serve as a hub cap)

This is a list of the tools I used. As with the parts this is just a guide and not a must have list.

• Safety glasses (Important: Lots of flying bits with this project)
• Drill press with appropriate bits
• Hand drill
• Drill bit/screw sizer
• Dremel (w/ giant heavy duty cut off wheels and grinding attachments) {or hack saw and files}
• Bench vise
• Clamps
• Ballpeen hammer
• Metal Punch
• Pop riveter (w/ appropriately sized rivets)
• Pliers
• Screwdriver
• Jigsaw

Look into the motor housing and determine where the magnets are placed. Draw a line down the sides where the magnets aren't located that will roughly split the housing in half lengthwise. Secure the housing in a bench vise and then use your Dremel with a large heavy duty cutting wheel to split the housing. When you’ve split the first side, rotate your piece around split the other side.

Once you’ve split the casing in two, change from the cutting wheel to the grinding attachment and clean up any sharp edges/scrap material on the edges.

Be sure to wear safety goggles of some sort!!! This process creates a lot of dust from the cutting wheel as well as sparks and little bits of metal flying everywhere. Breathing protection of some sort might be a good idea as well.

In order to make the sweeper cover a larger area we are going to join the two halves of the motor housing. We are also going to attach wheels, because otherwise it would be more of a magnetic scraper. To accomplish this I used a combination of screws, rivets and epoxy. Unfortunately the motor housing didn’t come with holes predrilled in the exact locations needed, which means drilling.

First place the two halves of the sweeper end to end. I chose to join the housing halves at the end with holes in the housing. (The holes will allow the epoxy we are going to apply in a later step to form a better bond.) Once you have the halves laid out, mark where you want the rivets to pass through. And remember to make sure there isn't a magnet on the other side!

Next flip the halves over and mark where you want the axles to attach. I figured this out by laying the future axle along the edge of the cut. Then I put the wheel in place to figure out how close I could get to the edge and still have it turn. Once I figured this out I marked the position of the threaded hole I wanted to use to secure the axle. Then I repeated this for the other side.

Now use your metal punch and ballpeen hammer to make a dent in the metal at each of these spots. I didn't do this and the drill bit tried to walk all over the place.

Use your screw sizer and figure out the diameter of the screws and rivets. Once you've got this info slap one half of the motor housing into your drill press. Make sure you secure the piece firmly. I improvised with spring clamps and cable ties. I encourage you to find a safer method. Now drill the appropriate sized holes for the rivets in the top.

For the axle holes the location I needed to drill was very close to the edge and the piece was nearly impossible to clamp to the drill press. So I secured it in my bench vise and drilled it with my hand drill.

Now clean up the edges of the holes with grinder attachment in your Dremel.

Next we're going to make the piece of metal that will actually join the halves of the sweeper together. Figure out how wide a piece of metal you need. I did this by laying the halves of the sweeper on a piece of scrap metal. I marked the metal just past the holes I drilled and marked the position of the holes. Then I cut the excess metal away from the piece I wanted. Once it was cut to size I dented the positions of the holes with my metal punch and ballpeen hammer. Next I drilled holes using the drill press at the marked positions using the same size bit as I used for the rivet holes in the motor housing.

Then you just need to clean up the edges and holes with your Dremel.

Get another piece of scrap metal. I choose one about an inch wide and three inches long. I marked two spots at one end that coincided with the rivet holes on the motor housing. Next I marked the locations where I wanted to place the screws that would secure the handle. With this done I once again dented each mark with a punch.

I drilled the holes located at the end of the piece with the same size bit I used for the rivet holes. Next I determined the diameter of the screws I would use to hold the handle in place, and drilled them out using a corresponding bit.

And then surprise, surprise I cleaned it up with the grinder bit in my Dremel.

Now we need to make it so your handle will be at a usable angle. Place the metal in your bench vise in such a way that the horizontal holes are slightly below the edge of the upper surface of the vise jaws. Bend the metal with your hand until it is close to a 90 degree bend and then give it a whack with your ballpeen hammer.

This step will have to be done relatively quickly once the epoxy is mixed up. Before you start gluing dry fit your rivets through the holes that were drilled in both pieces of scrap metal. If they don't go in, you'll need to drill them out a little more.

Once you’ve confirmed the fit mix up some metal bonding epoxy and then smear it on the bottom of the bent portion of the handle attachment point. Place a rivet in each of the holes and push the rivets through the corresponding holes in the other piece of scrap metal. Once this structure is in place, put rivets in the two remaining holes. Then smear the bottom of the second piece of metal with more metal bonding epoxy. After it is thoroughly gooified push the rivets through the corresponding holes on the two halves of the sweeper. Make sure the rivets are flush against the metal and then use the riveter to secure them. Allow the epoxy to dry overnight or as long as the directions state.

The rod I'm using for the axle is too long to be used in its entirety. To determine how far I could have each axle extend into the motor housing I aligned the threaded hole in the rod with the hole I drilled in the housing. Then I marked the point just before the axle encountered anything in the housing. I did the same for both ends. The rod was secured in the bench vice and almost completely cut through with my Dremel. If you cut through completely you run the risk of have the portion of the rod you want go flying off into the depths of your shop/scrap heap. Once you’ve cut off both ends, secure them vertically in the vise and clean up the cut ends with grinding attachment for the Dremel.

Mix up some metal bonding epoxy. Smear it on the surface of the axle you are going to attach to the housing. Line up the threaded hole in the axle with the hole in the housing. Thread the screw into the hole in the axle by passing it through the hole in the housing. Tighten the screw, with a screw driver. Smear a little epoxy on the portion of the screw that has passed through the axle and then secure with a nut. Repeat for the other side. Allow the epoxy to dry overnight.

With the axles in place it is time to get the wheels installed. I originally intended to make wheels out of medicine bottle lids, bearings and epoxy. However, my new ShopVac arrived and I was able to salvage the wheels from the vacuum it replaced.

Earlier we figured out the optimal placement of the wheels when determining axle position. Now we need a way to make sure the wheels don’t come off the axle. I accomplished this by using plastic buttons I salvaged from some electronic appliance. The buttons had a little hollow pillar thing in the center that barely fit over the end of the axle, but it wasn't a tight enough hold to keep the wheels on. So I used my drill bit/screw sizer to determine the diameter of the axle. Then I secured the buttons in the vice and used a bit the same diameter of the axle to widen the hole a little bit.

With that done I mixed up some general epoxy and placed a little bit in the newly widened hole in the back of the button. The tricky part is to use enough epoxy to secure the button, but not so much that it runs out and glues the wheel to the axle. Once you have the epoxy in place slide the wheel on the axle and then cap it with the epoxy treated button. Allow it to harden overnight.

Now we need a handle. I didn't have anything suitable lying around so I bought a 3/4" diameter dowel that was 4 feet in length. Since I'm tall this is good length for me. You may need to cut it down to make it more comfortable to use.

I placed the handle next to the handle attachment tab and used the holes in the metal tab as a template to mark where the holes need to be drilled. Then I secure the dowel in my bench vise and drilled the holes using a bit the same diameter as the attachment screws.

After the holes are drilled loosen the vise, rotate the dowel 90 degrees and re-tighten the vise. Lay the attachment tab against the dowel, and draw a line a smidge longer than the tab. Then use a saw to cut through the dowel along the line. (And of course I some how lost the pictures of this and the epoxy application I describe in the next paragraph)

Mix up some general epoxy and smear it on the tab. Insert to the tab in the slot in the handle and then pass the screws through the holes in the handle and tab. Apply and tighten the nuts with a screw driver and pliers.

Once the epoxy has hardened cut off and the projecting ends of the screws with a Dremel. Then pick stuff up.