Here’s an example of a really cheap scrub plane. I made it with a $5 old hybrid I picked up from an antique store. The hardest part of this was grinding the iron into a concave shape using a (you guessed it) grinder. I had some trouble getting mine evenly ground, but it worked great after I sharpened it up on my stone. I did have to widen the hole in the bottom up so it didn’t get all clogged up.
Here’s a pic of it in use on a slab of maple.
![scrub plane cleaning up some maple scrub plane in use](https://cdn.uploads.micro.blog/42912/2021/39b20c1e5b.jpg)
Here’s the iron after I ground it with a grinder and sharpened it up on a stone.
![ground iron, angled with grinder angled iron](https://cdn.uploads.micro.blog/42912/2021/0d87424d16.jpg)
And here’s the mouth I opened up with a chisel so shavings don’t get stuck.
![plane base, showing opened up mouth base of plane](https://cdn.uploads.micro.blog/42912/2021/6b2340c463.jpg)
One of these days, I’m going to pick up a weightier plane for a few bucks to make another one with more mass.