And here's the Youtube video i did of the sander. I go into a lot more detail about what i did and why i did it.
Strip Sander - Make Diy Build Plans
This is a project that i have wanted to make for a while now. It actually started because i wanted to buy the 1" x 30" strip sander from Harbor Freight. But when i went to look at the sander in person i changed my mind.
I've been meaning to make a flow chart on how i decide whether to buy a tool from Harbor Freight. I'll have to post one in the future. But the strip sander they sell would have failed miserably.
The strip sander wasn't cheap, i did plan on using it a lot, it's electric and got it got bad ratings.
I didn't think it was a tool i could make, the idea of a 1" strip of sand paper spinning perfectly centered on wheels i mounted seemed beyond my skill level. It wasn't until i saw Mathias build his version of the sander that i got excited again.
His sander has 3 wheels and therefore needs sandpaper around 36" in length. His 3 wheel design is similar to Harbor Freight's in that there is space in the middle to sand large objects.
I knew i couldn't build something that complicated. I didn't have the time or the ability. Also i felt that i didn't need to build it that way. I thought a 2 wheel version would work perfectly well, again the more basic, simple design is better.
So i looked online and found that knife sharpener designs looked like they would be perfect.
Another super basic design that i really liked.
It reminded me of the adjustable knife sharpener that Adam Savage has in his shop. I couldn't fine a picture of his exact one, but it looked similar to this.
My version would be along those lines but include a small sanding table surface. As always i drew up many many different versions on paper. The hard part was getting rid of pieces, trying to minimize the design down to it's basic parts.
Then i realized that to go farther i had to decide on a motor. And this is where i made an important decision on how the sander would operate. I have several motors on a shelf in my basement and i could have easily used a big 1/3 HP motor for the sander.
But that is the total opposite thing i wanted. The purpose of this sander was to be small, simple, compact, and used for sanding little intricate parts. The bigger electric motors would be overkill. That's why i decided to use a tiny electric motor from a cheap box fan.
To find out if that motor would actually work i decided to do a quick mock up of the sander. The motor was nice because it had 4 mounting points where it bolted to the old box fan. Those were perfect for bolting onto a wood frame i made. I ripped a 2x4 in half on the table saw, traced the shape of the motor onto the boards, ripped grooves around the motor, then drilled holes for the bolts. I was really happy with how the mounts turned out. You can kind of see here how i had to fit it around the motor.
Starting to take shape.
Next i got out an old roller blade wheel from a milk crate of wheels i had, put a bolt through it and attach it to a board. The roller blade wheel was perfect for size, width and it already had a great bearing in it. Also the inside of the bearing fit a bolt perfectly. Then i clamped that "arm" to an upright and clamped that to the base. I was happy with the basic shape of the sander. Then i had to cut out a bottom wheel, i just traced a roll of duct tape i had onto a board, cut it out on the bandsaw and drilled a hole in the middle. Later on i put a convex bevel on the wheel to keep the sand paper centered. The 1"x30" sandpaper was the only thing i really had to buy to make the sander, the rest of the stuff i already had in my basement.
I bought some 1" x 30" sand paper from Harbor Freight for around $3.50.
Or you can get the stuff from Lowe's which is $5.
When i put the sand paper over the wheels i had to tension the sand paper and clamp it down.
Here's another picture of everything just clamped together to see if the thing would actually spin.
IT WORKED!
Seeing the sand paper spinning around and not falling off, gave me such confidence to keep going. Before that i wasn't really sure, or wasn't sure if i wanted to build it. But after seeing it working i knew that it was going to be great.
From that point i kind of designed it as i went along. I didn't really have dimensions, and if i did, i kept trying to make it smaller and more compact.
I got a piece of plywood and marked where i thought the motor mount should attach. I pre-drilled holes then glued and screw it in place. Then i cut and attached the vertical board with glue.
I tried to make the base as small as possible. With the small base i had to also make a small sanding table. It basically acts as a platform to pivot the piece you are sanding. I could have made a pivoting table for sanding angles, but again the goal was to be simple and i'm glad i made a fixed table. Sanding angles can be done by just tipping the piece up or down.
Next was the design of the cantilever spring arm. Back to pen and paper to draw out 20 different versions, with how they were going to pivot and how the spring would attach.
Early stages of the 3 "alignment bolts". More on those later. But you can see part of the tension spring in this picture.
I found a spring that would attach at the back and provide the right belt tension. The spring attached to the end of the cantilever arm and then to the middle of the upright.
Again in keeping with the theme here, i wanted the table to be small.
From this point i could have made the table any size i wanted though.
Here's the board cut out and gluing up to the uprights. Some people might say, "why don't you make the table adjustable so you can sand different angles?" And i actually thought about that originally. But i figured it would be unnecessary and i could always hold whatever i'm sanding at an angle. Again, keep it simple.
Next was time to make the platten. I decided to use some bars of aluminum because it's easy to work with, easy to drill, easy to cut, and light weight.
The hard part was figuring out how to mount it. But i eventually realized that i could attach it to one of the table uprights.
You can see that i used a bolt with a thumb tightener so that i could adjust the platten so it is aligned with the sandpaper.
To make it i just riveted 2 pieces of aluminum together.
Here's the front side.
Next i decided to try and improve the roller blade wheel. It probably would have worked fine how it was but i wanted to make more surface area where it came in contact with the sand paper. That way it wouldn't have all the force just on the center of the paper. So i cut the wheel on an angle on the bandsaw.
I bolted the wheel on to a board, then clamped the board to the bandsaw table.
This turn out terribly. Instead of "cutting" the rubber, it just kind of melted the rubber and it got all gummed up in the bandsaw blade and wheels. It took a long time to get the rubber out.
Then i cleaned it up and made more of a bevel on the big disc sander.
It ended up working well. I'm glad i didn't just use the roller blade wheel as it was.
To keep the sand paper on the wheels you need some way of alignment. The bottom wheel can't move so the roller blade wheel on the cantilever arm had to adjust. I could have come up with a more elegant design but i figured that having 3 bolts push on the side would work. So i drilled and "tapped" the bolts through the upright. Applying tension of the 3 bolts would move the arm in and out and also angle it to keep the sand paper centered. To easily turn the bolts i cut some washers in half and welded them on to the heads of the bolts. Kind of like a wing-nut to turn with thumb and fingers.
Up to this point i always turned the motor on with the 3-speed switch from the box fan. I wanted to make it simpler with just an on/off switch. But i didn't want a huge outlet box on the side of this compact sander. So i looked and looked until i found a little box that would just fit a switch. From there i cut out a part of the box, cut a slot for the switch itself, screwed it to the side of the sander and then wired the switch. I kept the 3-speed adjuster knob and just screwed it to the side near the bottom. Kind of out of the way but still accessible. I didn't really get a good picture of the switch i made. But you can see here that i was still using the 3-way switch, which would have been fine.
Almost near the end.
Once i was happy with how it was working it was time to take it all apart.
Close-up of some of the pieces.
It was time to sand everything down, stain and seal it.
Another view of the pieces. You can see the original motor mount here too.
Instead of polyurethane i went with wax. Maybe in hindsight i would have polyurethaned it, it would have made it a little stronger of surface. But the wax looks fine and should hold up ok.
All Done...then.... uh oh.
I went to sand something and realized that the piece kept hopping up as i pressed on the sandpaper. The motor was spinning the wrong way. Somehow i missed that the entire time i was building it. It wasn't the end of the world, it still would have worked, but i wanted to see if i could get the motor to spin the right "downward" direction.
Long story short, i got it to reverse its direction by taking the motor apart and flipping the spool of copper wires around. There might have been an easier way but the motor was pretty delicate and glued and roped together.
Finally all done for good. You can see the switch i added here.
I always love using this sander when i need it. It is so convenient to just take out from under the workbench, plug in and use it. It can be a pain to have to clamp it to the table top, but other than that it's great.
