A while ago I bought a motorised lawn edging machine, and have already worn down a couple of blades. While the blades aren't super expensive I can buy a couple of metres of flat bar and a drill bit for the same price. The original blade was not made from hardened steel but was only mild steel. This makes sense as hardened steel is more likely to crack or break rather than slowly wear down.

I decided I was going to make my blades from now on.

Supplies

Flat metal bar (50mm x 3mm for my edger)
Drill & drill bits
File
Angle Grinder and cut disc or Hacksaw

Step 1: Cut the Bar

The first step is to measure how long the blade needs to be, I did this the last time I bought one. Of course, you could always be a little sneaky and measure one in the shop or look it up online.

Now measure and mark out the length of the flat bar you need for your blade. Once you cut it to length, it's good practice to quickly file off any burrs so you don't cut yourself while handling it.

Step 2: Mark the Centre

Now mark the centre of the new blade, the easiest way to do this is to scribe a line from corner to corner. Now use a centre punch to mark the centre in preparation for drilling.

Step 3: Drill the Hole

The first stage of drilling is to use a smaller bit to make a pilot hole, it's a good idea to use some oil or drilling fluid to lubricate this.

Now you should use a larger drill bit to drill out the hole to the correct size, I just bought a cheap one online. If you don't have a bit large enough use the biggest you have then a half-round file to bring it up to size. Be very careful to make sure the hole is centre otherwise it will be off balance.

Lastly, you may need to use a file to remove any burrs from around the hole.

Step 4: Install the New Blade

Now remove the old blade and install the new one. Just be aware that a lot of spinning tools use a left-hand thread, so it loosens in the opposite direction than normal, it's best to check the manual if you are unsure.