Lawmower Blades

[drentschler]

Can the Tormek be used to sharpen lawnmower blades and what other type of industrial related blades can it sharpen?  I looking to see what uses it might have in industry.

Thank you.

Dave

[Herman Trivilino]

I've been using my Tormek to sharpen mower blades for many years now.  The nice thing is that I can experiment with the bevel angle.  If the angle's too sharp, the edge folds over.  If the angle's too blunt, the blades of grass don't get sheared off cleanly.  The mark of a sharp mower blade is that the blades of grass are sliced off cleanly, with no ragged edges.  I guess that the quality of the steel has a lot to do with how sharp you can make the angle, and have it hold up without folding over.

Things with nice straight edges are ideal for sharpening with the Tormek.  Chisels and plane irons are the easiest to sharpen.  Scissors, too.  With a little practice, a person can learn to sharpen these like a pro.  In fact, when I buy a new chisel or mower blade, the first thing I do is sharpen it with my Tormek.  I can get a smoother sharper edge than the factory edge.
 
Hardcore woodworkers love them for sharpening the gouges they use with their lathes, and their carving tools, too.  These objects don't have nice straight edges, but Tormek provides jigs that solve that problem.

Paint scrapers are easy to touch up with the Tormek.  Having a nice square edge on the scraper makes the job so much easier. 

[Jeff Farris]

Dave,

While the Tormek can do a superb job on one's own lawnmower blade, to offer the service commercially would be asking for trouble. Most people, even professional lawn care companies, do not sharpen their mower blades often, and you would see some very blunt edges that would take a long time to reshape with a Tormek. 

[Herman Trivilino]

The shape of the blade is a factor, too.  Some blades have cutting edges that are curved.  I could never do a good job of sharpening those.

When it came time to buy a new mower, one of the factors I considered was the shape of the blade, and in particular, the shape of the blade's cutting edge.  One of the first things I did after buying the mower was purchase an extra blade.  It's a Bolens MTD 742-0642 twenty-two inch blade.  The factory edge on these blades is terrible.  I measured the bevel angle to be 25 degrees, and after using the blades for a while with moderate success, I perfected a technique.

I use the knife sharpening jig (SVM-45).  I set the angle to 22.5 degrees.  I use the same technique as I'd use to sharpen a wood chisel, with some modifications.  The first thing I do is clean the blade using a wire brush.  Just like a wood chisel, there's a side with a bevel and a flat side.  Keeping the flat side flat is essential.  I take sandpaper and clean the portion of the flat side that's near the cutting edge.  If necessary, I use a file on the flat side to make sure it's flat, removing any damage that may have been caused by the mower blade hitting something.  Then, using the SVM-45 jig I sharpen the bevel side using the same technique that I'd use to sharpen a chisel, with the following modification.  I take the blade over to my bench grinder and remove some of the steel on the bevel, but I'm careful to stay away from the region of the bevel that's close to the edge.  In other words, I remove some of the steel from the heel of the bevel.  This saves wear on the Tormek grinding wheel.  I move back and forth from the bench grinder to the Tormek machine, inspecting the edge each time.  Finally, I finish it off on the Tormek machine.

Now comes the tricky part.  It's hard to remove the burr with the honing wheel, so I developed a new technique.  I use a small sharpening stone, like the type you might use to sharpen a pocket knife.  I clamp the mower blade in my bench vise, and with a little oil as a lubricant, I gently polish the bevel, and the flat side near the bevel.  This works quite well.

And now, be careful.  You've got a very dangerous instrument in your hand, capable of doing some real damage to your skin.  I've got a nice slice in my finger to remind me that I need to be careful around sharp mower blades.

[Herman Trivilino]

After a month of using the sharpest mower blade I've ever seen, I have one bit of bad news to report.  I have to mow much more often!

Sharp blades should really be promoted as an environmentally-friendly way to keep your lawn healthy.  Don't need as much chemical fertilizer.  I really notice now how other lawns in the neighborhood get what looks like a brown frosting on them after they are mowed with a dull blade.