I always wanted to build something to sharpen by chisels, planes, etc. with a machine, not by hand. I do like my sharpening stone but sometimes you just need a lot to grind away.
It should be on low budget and preferably from as much recycled material as possible.

I had this old table saw, good for rough cuts but I never connected it to my sharpening-ideas, until I used it a lot in the reconstruction of some rooms in my house.

Step 1: What I Used

Tools:

Obviously a tablesaw
Drill press (or any other drilling tool)
Ordinary stuff like a scissor, wrench, etc.

Materials:

Aluminum disc, should fit the size of your tablesaw blade
sandpaper
double-faced adhesive tape

Step 2: Preparing the Disc

I replaced the saw blade with a similar disc, but without the saw teeth. The exact dimensions of the disc should be found on the tablesaw or manual or the disc itself.

Since I didn't had a disc that sice that was absolutely plain, I bought one aluminum disc from e*ay with the same diameter. It was slighty thinner the the original, but that didn't matter with the table saw I had. Especially since it would expand due to the tape and sand paper.

I located the middle of the disc with a nice little geometric trick. You measure a line from one side to the other ( not at the full diameter), take the midpoint of that line a draw a right angle from it trough the possible middle of the disc.
Do that twice from a different base line and you get the middle where the two lines cross.
See the little hand drawing for a better understanding (I hope).

Step 3: Drilling!

I wanted to drill a small hole first and widen it step by step, until I had the 16mm (about 0,6 inch) I needed to put the disc on the axis from the table saw.
But, unfortunately, I only had a 16mm wood drill - I used it anyway. The fear of a blunt edge was quickly replaced by the though of resharpening the drill with the tool I was building!

It did work - took a bit of time and was quite loud but it worked. Afterwards, I read to always set the drill to high speed if drilling in aluminum. Can't say if that would have been easier, I'm trying next time.

After that, I put the double-faced adhesive tape to the disc and sticked the sandpaper to it.

I started with a 180 grit for metal on one side and 600 on the other.

Step 4: Preparing the Table Saw

NOTE: Always use caution if working on such a tool. I don't know your tablesaw, there could be issues that collide with the way I upgraded mine. If you have a bad feeling about it, don't do it.

First I had to unscrew the "saw- and splashguard" (don't know the name, it was the cover for the sawblade beneath the top) and the loosen the nut that holds the sawblade. In my case, a 8 and 19 wrench did the work.

Then I could easily remove the table saw blade.

I noticed this little metal spring that presses against the saw blade - figured to better remove it, it would ruin my sand paper on the disc.

Step 5: Put It All Together

Finally, I put my sanding disc into the table saw. Looks great!

I put all the screws back in place but removed the cover lid the saw blade for easier access.

I had this big magnet for cleaning an aquarium when I was a kid. Could come in handy in keeping my workshop clean. I wrapped it in aluminum foil, that way I could remove the iron particles from the sharpening easier. One part I placed on the table itself, the other one on the bottom at the output-/hoover-shaft.

Step 6: Test It!

Let's go!

Got this old chisel from my father-in-law, I'm going to breathe new life into it.

Step 7: Conclusion

Nice :)

Worked like a charm.
Though I do need more experience to handle the issues of the heating of the blade. Sprinkled some water on the sand paper and cooled the iron every few seconds in a cup of water.

Second problem is to keep the right angle. I noticed that the blade/disc isn't exactly at 90° to the top.
I think I need some wood to guide my chisel. Stay tuned ;)

The magnet worked fine, although only within a exact distance from the sharpening.

I don't know if the tape/sandpaper combination is the best. It holds well, I'll tell you more if I'm going to replace the paper.

The splitting wedge behind the disc is pretty useful as tool rest or for a steady hand. Just watch the disc and wear gloves!

Thank you for watching!