Blade Sharpening and Maintenance

[Botman]

Let's discuss methods to maintain the blade!  About one a month I generally will remove the blade, clean off buildup that has accumulated and will sharpen the blade.  If the grass is growing fast I sometimes will clean it off every couple of weeks.  For sharpening, I use a Corona blade sharpener.

http://www.acehardware.com/product/index.jsp?productId=2260310&CAWELAID=109394929   

[toolbelt]

I have two blade.  One is always sharpened waiting to be used.  When time comes to sharpen the blade I let the blade soak for a few minutes, then scrape off the grass using a putty knife.  Then I lay the blade on the work bench with just an 1/8 inch of the blade overhanging the edge.  Using a bastard file

http://www.sears.com/shc/s/p_10153_12605_00931265000P?prdNo=3&blockNo=3&blockType=G3 

I run the file against the blade.  Makes quick work of the job.  I have used the same tool you suggested but the bastard file works much faster. It also takes nicks out of the blade.

For those worrying about taking off too much metal off one blade, forget it.  I've been doing this for 4 years now on just two blades and nothing has shaken loose.

[RobotLady]

We have a concern that blade sharpening could contribute to motor problems.  Not factual; just a concern.  We are wondering if the blade can become imbalanced if it is not sharpened evenly.  An unbalanced blade could stress the motor. 

Due to this concern, and the fact that Zucchetti has never said it is ok to sharpen the blade, we no longer recommend sharpening - to be on the safe side.

It sounds like some have had good luck with sharpening.  It is possible our concern is unfounded.  Since there is uncertainty about it, we plan to stick with our more conservative recommendation to replace rather than sharpen the blade.

PS, In case you are not aware, if you have a model with the straight, non-bent blade, you can flip it over mid-season or whenever it seems dull.  LB3500 and LB3510 use a bent blade, so unfortunately this is not possible on those models.

PPS, It is time to replace your blade when the tips of the grass turn brown.

[toolbelt]

Ahhhhh come on, if the motor is going to be burned up because a little metal is removed when it is sharpen then it's sure as heck is going to burn up with all of the grass that sticks to it!!!  Let's get real here folks.  Clean and sharpen the darn blade and get on with it.  Your motor will love you for doing so.  Grrrrrrr

[Botman]

Not to disagree with Robotlady, but I don't know how sharpening an edge of a blade which would cause less strain on a motor vs the buildup that normally occurs with mowing....  Now if you were taking a grinder and removing a significant amount, that would be a different story.

[RobotLady]

I openly agree I could be wrong, so it is in no way a strong recommendation to replace rather than sharpen.  I'm sticking with the more conservative recommendation because I am not 100% confident consumers sharpening their own blades is a good idea.   Use your judgement based on what you think is the best course of action.

[yyzdnl]

An out-of-balance blade can cause vibration and damage to any lawn mower.  If you want to sharpen your blades I would recommend using a blade balancer.  An inexpensive cone balancer can be purchased at most any hardware store.

[Modog]

As a guy who has been sharpening the blade lightly with a bench grinder for the past 3 years, I think the insignificant difference of the weight of the metal lost on all sides of the blade and the light weight of the blade itself would never make the blade motor self-destruct.  Buy a new blade for $70 but I will continue to sharpen my 3 blades.  I too let my blades soak in a flat 1/2 inch deep pan with some degreaser solution.  I use a BBQ grill scraper instead of a flat-bladed scraper and the old grass build-up comes right off.  I also only sharpen one side of the blade, not both sides of the blade since the blade only rotates in one direction.  I change my blade about every 2-3 weeks as I feel guilty for now having to mow and it only takes 2 minutes.  My weedeating looks significantly better since Modog has been mowing daily.  I've noticed that the more Modog mows, the less he has to rev his blade motor higher to cut the thinner grass which makes his battery mowing sessions last longer.  cool.  I have a 0.75 acre yard.

[jzawacki]

Well, I'll post my experience and you can take what you want.

In the beginning, after spending $3,200 on the bot, I didn't want to take any chances, and was purchasing new blades.  Then after reading about using a scissor sharpener, I decided to give it a try.

Now, after having ripped these motors down and rebuilt them myself enough times, here is my feeling.  My blade motor had no "out of the norm" issues with sharpening and has been running great since I replaced the brushes.  There is no real way to say if my brushes wore out premature (they were 3 years old, if I remember correct) and if they did, what caused it.

When it comes to blade balance, the obvious answer is going to be that they should be balanced.  But, if you consider the amount of metal being removed when sharpening vs. the amount of the balance change for.. say, a chip or grass, all of our bots would be falling apart due to blades being unbalanced.  If you consider the environment that these motors are operating in, a few swipes of a scissor sharpener on each blade shouldn't have much, if any, impact on the blades balance.

Now, at the same time, a razor sharp blade that you could shave with is going to reduce the stress on the motor cutting the grass... but, we're talking about grass here.  As long as the blade isn't tearing the tips off, and is actually cutting them, I think your blade is sharp enough.  From what I've seen, several swipes across the blade to sharpen it is sufficient.  I have 4 spares that I keep sharpened and ready to go, only because I didn't throw them out when replacing them the first year.

But, if you are worried about it, do like yyzdnl said and get a balancer.