Convert a Grindstone to Treadle Power




About: Interested in practical and hands-on self sufficiency and rediscovering lost arts.

Before the advent of electrical power in homes, a wide variety of tools and machines were powered by humans and animals. From the 1800s to the early 1900s, human powered tools were widespread among homes, farms, and businesses. In this instructable, I'll show you how I converted an electric motor powered grindstone into a treadle powered tool. I chose to do this because my workshop is not powered and it isn't practical to run several hundred feet of extension cords. It's also not a bad way to get a little exercise!

Step 1: Tools and Materials

Materials Used

(Apologies if I do not know or remember the proper name of something I used. I included pictures to help you out)

1 tool to be converted
1 3' section of 1/2" round steel stock
6 1/2" washers
1 3' section 1/4" threaded rod
2 1/4" connecting nuts
2 1/4"x3" eye bolts
1 1/2"x4" hex bolt
1 1/2"x3" hex screw
1 1/2" nut
1 1/2" nylon locking nut
1 piece of 3/4" thick hardwood
Section of 1/4" plywood
3 or 4 2x4 boards
3/4" plywood for treadle pedal and table top
Wood screws ranging from 1" to 2 1/2" in length
Wood glue

Tools Used

Hand/miter saw
Chisels (optional- for mortise and tenon construction)
Hand Drill
1/2", 5/16", and 1/8" drill bits
Screwdriver bits
Measuring tape
Adjustable square
Metal file
Adjustable wrench

Step 2: Modify the Drive Pulley, Part 1

In converting my grinding wheel to treadle power, I wanted to avoid physically altering any parts of the grinding wheel. Instead of drilling through the drive pulley, I decided to make a wooden insert that would support the hardware being driven by the foot treadle.

First I traced the inside of one of the pulley segments onto a piece of poplar wood that matched the pulley's thickness (Picture 1). In this case, both the rim of the pulley and the wood were 3/4" thick. I then cut this wedge out and sanded and trimmed this piece until it fit snugly into the pulley (Picture 2).

Step 3: Modify the Drive Pulley, Part 2

Next, I made 2 outer pieces of wood that would sandwich the piece of poplar into the pulley wheel. I traced outside of the pulley spokes and the outer rim (Picture 1). The size of these outer pieces are shown in Picture 2.

Picture 3 shows one outer piece in place on the pulley. Attach both outer pieces with short screws in case this needs to be removed at a later date. The wood should be secure and not have any wobble to it.

See the next step for the completed view of this step.

Step 4: Add the Drive Hardware

Next, I added the assembly that would turn the treadle power into rotational power. To do this, the treadle needs to be attached to a point offset from the drive pulley's main axis. I chose to offset by about one inch so that I could achieve higher speeds with my grinding wheel. Placing this assembly towards the outer rim of the pulley would allow higher torque but lower speed per rotation.

Drill a hole through the wooden pieces that is wide enough to fit a thick bolt (Picture 1).

I used the following hardware to make this assembly:

1: 1/2" x 4" hex bolt
4: 1/2" washers
1: 1/4" x 3" eye bolt (Chosen because the eye was 1/2" in diameter and would fit on the main bolt)
1: 1/2" hex nut
1: 1/2" locking hex nut (nylon insert nut)

The hardware and its installation order, from right to left, is shown in Picture 2. I had to file down the inner-most washer to get it to fit against the pulley (Picture 3).

Pictures 4 and 5 show the completed assembly installed on the pulley. Make sure not to tighten the locking nut too much- the eye bolt should be able to turn freely between the washers. This is necessary for the treadle to work.

Step 5: Build a Stand

There isn't a lot I can say about this step since you will have to build your tool's stand to the size of yourself and the tool itself. In my case, I built a stand that is 36" tall and 18"x18" square. Build your stand as square and as sturdy as possible. I used 2x4 boards and mortise and tenon construction. I also added adjustable feet to the legs of my stand to help keep the stand level. I recommend painting the stand to protect it from wear and weather, but it's currently too cold here for paint to set properly.

IMPORTANT: Leave at least one side open at the bottom, as shown in Picture 1. We will be mounting the treadle here later.

I added a central beam to support the weight of my grinding wheel. If you choose to do this, make sure it will not interfere with any mounting bolts for when you attach the tool to the top of the stand.

For the top of my stand I used 3/4 plywood and dimensional lumber that were scraps in my shop. The total top measures 24" x 24" to give some overhang on each side, as I will be attaching several other tools to the edges of my stand.

Before attaching the top to the stand, mark and drill any mounting holes, as shown in Picture 2. You will also need to cut a hole in the top that the pulley wheel (if applicable) and the treadle rod will fit through. This hole will need to be long enough to account for any horizontal movement of the drive assembly from Step 3, as well as allowing the drive pulley to turn freely. Picture 4 shows a front view of the clearances allowed.

Step 6: Build the Treadle

Now it's time to start building the treadle that will power the grinding stone.

The treadle consists of a slab of wood which will be worked with your feet up and down to provide power to the grinding stone. I shaped mine to my dominant foot, but this is optional. I used a scrap piece of 3/4" plywood that was 12 inches wide and 18 inches long. As shown in Picture 1, I decided the pivot point of the treadle would be 4 inches from the back of the board and provided one foot's length of room in front of this point. The part of the treadle behind the pivot point is where your off-foot presses down to bring the treadle back up to repeat the cycle. Picture 2 has another view of the shaped treadle paddle.

Next, cut a piece of 2"x2" square stock that is as wide as the treadle paddle. I used a hand plane to smooth out what the down side would be. Using a router, chisel, or combination plane, make a groove 1/2" wide by 1/2" deep. In the next step, you will use a piece of 1/2" steel round stock to create the pivot for the treadle. This grooved block is what holds the paddle onto the steel (Picture 3).

Center the groove over the pivot point on your treadle, as shown in Picture 4. You will want this to be as centered and straight as possible. Secure the two pieces together using glue or screws.

Step 7: Installing the Treadle

To install the treadle, drill 2 parallel 1/2" holes through the front open space in your tool table. I put mine 4 1/2" off the ground based on what was comfortable for me. This is the height at which the treadle will pivot. Check to make sure your steel bar will fit cleanly through the holes (Picture 1). Cut the steel rod to length using a hacksaw. I let mine stick out about a half inch on each side of the table legs.

Next, make and attach the lower drive assembly to the treadle. As shown in Pictures 2 and 3, this is a simple assembly with a tapping hex bolt holding 2 washers and an eye bolt for a drive. Don't drill the pilot hole too large. Use a wrench to tighten this assembly into a block of scrap 2x4.

Using a connecting nut, I screwed in the 1/4" hex rod to the top drive assembly, as shown in Picture 4. This let me see where the rod would hang down so I knew where to install the lower assembly. In Picture 5, I had to cut 1" into the side of the treadle before mounting the assembly. Picture 6 shows another view of the assembly and the threaded rod lining up.

Step 8: Hooking It All Together

Lift the treadle up by the eye bolt until it is horizontal, which will be the resting/downward position. Mark and cut the threaded rod so that it comes to the top of the eye bolt. Using the second connecting nut, connect the threaded rod to the eye bolt as shown in Picture 1.

Note: The second eye bolt may not thread well onto the threaded rod. It might be easier to partially disassemble the drive mechanism and thread everything together, then reattach it to the tool.

You now have a treadle powered grind stone!

Picture 2 shows the treadle at rest, while Picture 3 shows the upward or highest position. Using this setup, the treadle will tend to come to rest at the downward position. To set the treadle in motion, spin the drive pulley towards or away from you as the working motion of the tool dictates. In this case, I spin it away from myself. This pulls the treadle up, where I can press down with my right foot. To continue the cycle, alternate pressing down with your front foot (to press down) and your rear foot (to bring the front of the treadle up). It can be a tricky motion to get into, but it's like riding a bike- easy once you've got the motion down.

Feel free to ask if you need any clarification; otherwise, I hope this helps. Keep calm and treadle on!



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    31 Discussions


    10 months ago

    I have an old forge blower that can use this power. I'm sure I can entice some of the younger folks around to operate the blower while I hammer.


    3 years ago on Step 5

    I don't know if you went to college or not but they don't teach you to think like this. I guess maybe engineering but sometimes they seem to have a very narrow focus. I feel like the only way to understand this type of making is by making- mistakes as well as successes. And hopefully someone to back you up while you are learning. What do you think?

    1 reply

    Hi, Terrefirma. I'm actually a geographer by profession; I never did well enough in math class to consider engineering. But I agree wholeheartedly- trial and error is a fantastic way to learn things. It's how I've learned most of the skills I have for making things like this. As Thomas Edison (reportedly) said, "I haven't failed, I've simply found 10,000 ways that didn't work."


    4 years ago on Introduction

    One idea I've thought of , but never tried, is the horizontal shaft with a leather strap wrapped in a spiral around the shaft, one end down to the pedal, the other end to a light spring that adds a slight tension to the strap. This provides for a long stroke on the pedal and a clutch of sorts on the return. Anyone try this please- I don't think the idea is original !


    4 years ago on Step 8

    No welding or forge needed , that works .


    4 years ago on Introduction

    I was thinking of making my hand cranked grinder Like the one seen in the picture) into a foot powered one as it slows down so quickly when I let go to grind.


    4 years ago on Introduction

    I LOVE IT! i've been looking to figure out how to make a foot treadel mechanism, but now i don't have to. putting this one in my favorites list for sure.

    1 reply

    4 years ago

    Thanks. I've had a project t like this in mind. I have an old hand crank craftsman that I've been thinking about trying to convert to a treadle power. This'll give me a little bit of a head start.

    1 reply

    4 years ago on Step 8

    Thanks for posting. I have this same grinding machine plus a handcranked one a bit bigger than yours. Nice to see a functional setup. It will save some time when I do my own, even if I retain the electrics. I can see this with the mitor drive underneath. Nice and tidy.

    Do you find the working height on the hand cranked wheel sufficient? Maybe you could hook that to the treadle eventually as well? I never figured out how to sharpen something one-handed in those things ?. The one I bought has a clamp for the tool, but still only good for single angles at a time. Chisels and plane blades and such.

    The big grinder, I was told, you could buy at some stonemason supply store in New York state. Never managed to track them down to see if they were still open.

    1 reply

    Reply 4 years ago on Introduction

    I haven't used the hand grinder yet, but with the stool I have it seems to be at a comfortable height. I could probably hook it up to a treadle easily enough but I don't have any plans to currently. I've also looked at trying to get a replacement/spare stone, but I haven't had any luck, either. It'd be nice to have that peace of mind.


    4 years ago on Introduction

    If you reverse the pulleys small to large so you are speeding up the stone you will find it works much better. The pulleys were set up to slow a electric motor, your foot needs speeding up not down.

    2 replies

    Reply 4 years ago on Introduction

    You're right! I hadn't gotten around to reversing the pulleys when I was writing this up. I've switched them around and put a new belt on and it still works great.


    Brilliant! Electricity and gasoline have their places but I hate relying on them where it's not necessary. I take my hat off to you, sir!


    4 years ago on Step 8

    Fantastic! I've been planning on doing a similar project, but building a treadle powered lathe. I'll be definitely following your advice :)


    4 years ago

    I agree. very well done and it's cool to use human power!