Bench grinder tool and lawn mower blades

[raymondj]

Does anyone use a bench grinder to sharpen lawn mower blades? If so can you tell me your recommendation and experiences. I am looking for something where I can get the angle right and won't take forever (like with a dremel.) I have a bunch of blades to sharpen each year and I just want to bang them out (and not have to drive to the shop and wait

2 weeks for them to be sharpened.)

I see the Delta sharpening kit has terrible reviews (as do most of the delta bench grinders.) I did see a special bench grinder with a jig made for lawn mower blades to set the angle, but the unit was close to $300.

Can any of the Jet, Baldor, etc be equipped to easily sharpen blades accurately?

[Greg]

I do mine by eye, just trying to match the original angle. I set the little guide in gront of the wheel if I am really serious but I am usually just trying to get the dings out.

[Greg O]

I used too run a small engine shop, so I have sharpened a ton of mower blades. Yes, a common bench grider will do a good job, but one day I grabed my

4-1/2" DeWalt angle grinder to sharpen a blade and never used the bench grinder again! Clamp the blade in a bench vice, hold the grinder with both hands, use the accessory handle, hold the grinder against you stomach for extra stability, and grind away! I can sharpen blades that look like they were done on a machine. With a little practice you will get the knack of holding the grinder so the angle stays constant. Instead of moving the grinder with my hands I sway back and forth moving my weight from my right and left foot. I have had people ask what kind of sharpening machine I use because the blades look so good! A good friend, that mows lawns for a living, sharpens blades the same after watching me do it. DeWalt 4-1/2" angle grinder, about $90. Greg

[Edwin Pawlowski]

Belt sander. Takes about 45 seconds a side. Put the blade in a vice and give it a grinding with a course grit paper.

Just follow the existing angle as best you can.

[bert&ernie]

I just take the blade off, stick it in the vice and use my angle grinder to sharpen it. I never found where the angle needs to be all that precise, as long as it is sharp. However, you want the blade balanced. In other words, if you take an ounce off one side, do the same on the other. You can buy little pointed blade balancers for a couple bucks, and they are worth the money. If the blade is not balanced, the mower will vibrate badly.

[Gary Dyrkacz]

... I have a Craftsman bench grinder which I have used for years to sharpen the blades. The angle may vary a bit unless you make yourself a jig, but worrying about the difference is probably overkill. Just try and stick to the original angle as best you can. The only thing I have to really worry about is accidently contacting the second wheel which I have set up as a buffing wheel. To avoid that, just make sure to put the grinding wheel on the left side.

I just bought an angle grinder for other reasons and will probably give that a try for the next sharpening.

Gary Dyrkacz [e-mail] Radio Control Aircraft/Paintball Physics/Paintball for 40+

[JerryMouse]

Use anything, from a hand file up to a milling machine.

You're not going to use the result to plane antique mahogany furniture, for heaven's sake - you're cutting grass!

[Greg]

My thoughts exactly. It's just grass.

There is so much sand in my yard that I end up wearing out a blade in a year anyway. I sand blast away so much metal that the tips fly off if I don't.

[xrongor]

if you cant get it sharp enough with a hand file without removing the blade, you will likely throw the blade out of balance unless you take steps to prevent this. this will shorten engine life at best and kill you at worst.

randy

[Stormin Mormon]

Don't need accurate. Just grind the bevel side.

Drive a nail in the wall behind your work bench. Hang the blade on the nail (nail goes through the center mounting bolt hole). Make sure the blade doesn't rub on the wall.

Hold the blade horizontal, and then let go with your hands. One end of the blade will go down. That's the heavy end. Grind on the heavy end for a couple more seconds.

Repeat until the blade hangs horizontal.

Remit $48.50 for consultation, please.

[Chet Hayes]

I agree with the advice to use a hand held grinder. It's fast and easy and I prefer it to even a bench grinder.

[Stormin Mormon]

I read through several posts, and I was the only one who told him how to balance the blade. Hope you fine gents can learn from my experience. Hey, that would be $48.5o from each of you.... I like that idea!

[raymondj]

This sounds like a good idea! I already have a Dewalt 4.5" angle grinder. What type of grinding device do you use? Just a metal sanding disc? Do you grind using the flat part of the disc or do you use the side (as if you were using a metal cutting disc) ?

Thanks for the good idea.

[Nick Hull]

When I was a child, my older brother removed the blade and got it real sharp and we used it all summer. The next spring he took the blade off to sharpen it, and it was still razor sharp because he had installed it upside down so we were cutting with the unsharpened back side of the blade. No one had noticed any difference in cutting power.

I have used my bush hog for 25 years and haven't sharpened it yet.

[Greg]

Right on. I am giong to go with my 4" Makita next time.

[Greg O]

I use the standard 4-1/2" grinding disks, about 1/4" thick. Hold the grinder so just the edge of the wheel touches the blade. I usually mount the blade in the vise so the edge I am sharpening sticks out the left side of the vise and points up. Greg

[George E. Cawthon]

My pointy blade balancer is a nail. Stick the nail in the vice (horizontally) put the center hole of the blade on the nail and let the blade swing. Grind the swing down side.

[raymondj]

HA. You are supposed to use the little cone shaped thing to balance the blade in all planes. Your method is usually good enough though.

[raymondj]

I thought I only had to pay if I use your idea. You know, like licensing and stuff. Say 10 cents per each time I balance a blade?

[Chet Hayes]

Perhaps you can provide us with a link to anyone being killed by a mower blade that was sharpened and not balanced? Sure, it can make the mower vibrate, but long before anything life threatening would happen, the mower would be vibrating so badly that only a fool would try to use it.

And balancing it is quite simple, you can buy a plastic cone type balancing gizmo at home centers for a couple of bucks.