Sharpening Shovels – Why and How
Bucking the trend at showing the "finished" photo first, this is actually how bad a shovel can look if you don't care for it at all. Next up is how it looks after going through the following process!
But wait — why would you want to sharpen a shovel? They don't ship from the factory sharpened? It's because using a blunt edged shovel vs a sharp shovel is like night and day. The sharp shovel takes far less effort to use and glides through vegetation and soil like butter. After using a sharpened shovel, you'll never want to use one that isn't. And you can get all this with only 10 minutes of work!
Are you more a fan of moving pictures than still pictures? Here's the YouTube video: www.youtube.com/watch?v=YFLnn-w8yg0
Yeah, this is the same shovel as the prior picture. It's amazing what a little TLC can do. This almost looks like new.
It's not the focus of this album, though… just an example of an extreme.
Rusted and Uncared fore
The shovel in question isn't quite as bad as the teaser, but it's still bad. The rust made it hard to move through the earth and the blunt edges certainly didn't help.
Remove Rust with Sandpaper
Sandpaper is surprisingly effective at removing rust. You want to tailor the grit to the type of rust, though. Coarse grit (60, 80) works well for thick and chunky rust but is terrible for fine rust. This shovel had only fine rust and so a fine grit (220, 320) works far better.
A sanding block does a fine job, although it does take awhile and it can't touch the embedded or pitted rust
If you have a random orbit sander then more power to you! It has the same advantages and disadvantages as the sanding block, but does it all quite a bit faster. Neither the block nor the RO sander can get the recessed areas. Loose pieces of sandpaper work well there.
Wire Cup Brush
Sandpaper can only go so far. If you want to remove rust a lot faster and get the pitted rust plus some of the recessed areas, then a wire cup brush is the way to go. This is a twisted wire cup. It's very aggressive but also fare more sturdy than the loose wire cups. Those tend to lose wires all over the place.
Grinding Away the Rust
Attaching a wire cup brush to your angle grinder makes fast work of the rust. It'll get all but the most hidden areas and close to the edges. It works very fast, too, due to the high RPMs of the grinder. I still use a loose piece of 220 grit sandpaper after the grinder is done to touch up the few areas that the wire brush couldn't get to.
All clean! It could look prettier with more sanding — maybe all the way to steel wool. All I cared about at this point was removing the bulk of the rust
One way to sharpen a shovel is to use a metal file. The typical file to use is a "bastard" file… which just means that it's neither fine nor coarse. You can actually use any file that isn't coarse. Note that files tend to have their teeth pointing forward. You can feel that with your hand or see it if you look close. It's important to never "pull" the file backwards or to use a sawing motion with it since that'll dull the teeth. Always use forward strokes.
Put your shovel in a vise with the blade facing up at an angle. It doesn't really matter what angle. The goal is to grind away the edge to make a flat plane rough parallel to the ground. This flat area will form a bevel with the existing angled edge to form a sharp edge. Hold the file with both handles and make steady and firm forward strokes. Pull the file to the side as you do that to "draw" the stroke down the side of the shovel. You only need to sharpen the first maybe 1/3 of the edge. The first time sharpening will take only a few minutes with a metal file
But maybe you want to do the initial bevel creation even faster. That's where a metal grinding disc on an angle grinder comes in. This is a 1/4" grinding disc or wheel. It is typically used to grind metal welds flush. If it can do that, then the relatively soft steel of a shovel won't put up any challenge at all
Grinding the Initial Bevel with an Angle Grinder
The angle grinder removes a lot of material very quickly. Too quickly if you're not careful! Also, if you hold it down in one place to long then it could heat up and "detemper" the steel, making it even softer. As such, just make quick and light passes with the grinder. Keep the disc parallel to the floor just like with the file. It'll work far far quicker than the file — you can make the bevel is less than a minute, easily.
The grinder will leave circular marks in the bevel so I typically follow up with a few draw strokes of the file to smooth it out a bit. This doesn't need to be perfect. You're not expecting it to be knife sharp nor do you expect a mirror finish like on a chisel. It will be sharp enough to cut you, though, so be careful.
You'll want to protect the shovel from future rust so apply a coat of oil to it. Boiled linseed oil is frequently recommended. I'm using a Rustoleum Rust Inhibiter spray here, which also works great. I just spray it on and then wipe off any excess. This shovel is now ready for duty and works almost immeasurably better after only 10 minutes of work! In the future, you can touch up the sharpened bevel with the metal file in just a few strokes — quick and easy.