Sharpening Blades

[c3po]

My Dad and I went in on a Grinder, and he is really good at sharpening blades, I have a small lawn mower that I use 3 hours a week to cut a few lawns, how often should I be sharpening my blades.

My Dad has a Cub Cadet Tractor that he uses for about 1.5 hours each time he cuts the grass, sometimes he cuts the grass twice a week, is there an hour limit he should go by in sharpening up his blades.

 

[JimPghPA]

Once or twice a summer is normal.

 

[SrDriver]

Don't forget to balance them too. I use a round screwdriver. If the blade tips one way, I grind a bit more off.

Wal-Mart and others sell an inexpensive blade balancer.

You can use a nail driven into a tree or board, etc., too.

 

[c3po]

Originally Posted By: SrDriver
Don't forget to balance them too.


I forgot to mention that we did buy an inexpensive blade balancer, years ago I worked in a lawn mower repair place helping customers so the mechanics could keep working on the equipment, and I remember the guys balancing the blades, they had something mounted on the wall.

I remember when we got the Grinder and I called up one of the mechanics that used to work there and he mentioned getting a blade balancer.

 

[JTK]

It depends on your conditions. I can go years between sharpenings with my 1.5acres of closely-cropped weeds. Even with a bench grinder, I've never been good at a achieving a nice consistent edge and usually take them to the closest mower shop. I may try filing them some time.

Joel

 

[SuperDave456]

I sharpen at the end of every season.
I use a coarse file, then a fine file, then coat the white metal with some CLP.

My blade balancer is a nail in the wall. Ive never had an issue.

 

[Deltona_Dave]

For balancing, I use a 5/8" bolt about 4" long in my vise (My blades are star-drive, so a nail does not work too well. I have an old slow speed wet (tormek) grinder for my blades. Not fast, but leaves a nice edge.

Easy way to tell if the blade is getting dull, is to look at the cut grass blades. If they are getting fuzzy, time to sharpen. If the blades are clean cut, the blade is okay.

Florida Bahia grass is like cutting steel. Dulls blades after about 3 mowings. I have about an acre.

I keep 2 sets of blades. One on mower, one on "standby". The blades are shot by end of season, the sandy soil erodes the sails.

Dave

 

[c3po]

The place where I bought my mower does blade sharpening, but you have to leave the blades there, and you cannot wait, and when I found out that they wanted $10.00 to sharpen a blade, I knew a Grinder was the answer.

My Dad's riding mower has 3 blades on it, and I was afraid that with the cost to get his blades sharpened being almost $30.00 that he would slack off on getting his blades sharpened.

Also, I am sure he can use the Grinder for other things, he could probably put on a Buffing Wheel if he wanted to polish something.

 

[ccs v2.0]

I tried the DIY sharpening but it took me too long to get it done (plust I don't have the patience) and my local hardware store charges $8 but they also keep it for a week. My answer is to have a second blade so I don't really have down time.

 

[Dieseldoctor]

The easiest and cheapest way is get a inexpensive grinder take the guards off and turn it around mark on the body of the grinder 0 degrees straight up... then go 1/4 way around roughly 90 degrees then half that to get 45 degrees then 1/2 then try and mark 30 degrees roughly. Then simply hold the blade flat and keep it between the 30 and 45 degree angle.. then move it to the 0 degree straight angle on top to get the bottom. That's the easiest way to get a perfect blade thats not too shallow of a angle. I have several blade sharpening books i got for sharpening hand knives and shows in pretty good detail how to sharpen about anything. I'd love to find a tomak sharpener they're like 800 dollars a nice used one would be gold!

 

[boraticus]

I've been using a bench grinder for decades to sharpen lawnmower blades. Takes about three minutes to do both ends of one blade. Works great. Never had a balance issue and seldom if ever even check the blade. It would take a fair amount of difference in material removed to upset the balance. I usually eye ball the blade. If it looks a bit off, I'll just clamp 1/2" drive extension into the vice and set the blade on the wide end. Usually after one cutting, the blade accumulates enough grass clipping residue to effect the balance. From my experience, it has to be off by a fair amount to cause vibration.

 

[Colt]

I have two blades and go 1/2 season with each.
$4 per blade to sharpen at the hardware mower/snowblower store.
Change the oil and use Amsoil small engine oil at the same time I change the blade.

 

[greenaccord02]

I have several blades that I use and my bench grinder has never failed me. It may take a little practice to get a good edge, but once you develop a feel for that angle, it's as natural as anything. I balance on a nail and use a level to make sure it's right. I then sand off any rust that might have developed and coat it with a coat of rustoleum spray paint. I only sharpen once per season per mower. Usually by the winter the grass starts to look less clean-cut, but I don't care because it'll be dead soon anyway.

 

[c3po]

http://www.youtube.com/watch?v=9lLnYpW_OMY&feature=related

Nice Video on Sharpening Lawn Mower Blades

 

[nitehawk55]

I've always used a grinder with the guard off so I can sharpen on the side of the grinding wheel while resting the blade on a block of wood (ALWAYS wear eye protection ) . I get my angle right and when done put a round shaft screwdriver through the bolt hole of the blade to see if it is still balanced by the blade remaining static when horizontal , side that drops gets a wee bit more taken off till it does stay horizontal.

BTW , "eyeing" a blade cannot in any way tell you if it is balanced and grass clippings that stick to the blade have little effect on the balance . If you run blades that vibrate it will take out bearings in a deck hub or cause wear at the crank/block on a push mower engine . Any small variation in balance will cause vibration , small amounts you may not feel but it's the same as having a tire on your car a bit out of balance .

 

[boraticus]

Originally Posted By: nitehawk55


BTW , "eyeing" a blade cannot in any way tell you if it is balanced and grass clippings that stick to the blade have little effect on the balance .


Maybe to an inexperience person.

I've seen mower blades with as much as 1/8" thick or more of dried or moist grass residue stuck to it. Sometimes, one side of the blade will throw a chunk of dried or wet grass residue that weighs much more than a hair's thickness of steel. I'd say that will have more of an effect than .05 grams of metal imbalance.

It takes a fair amount of imbalance to induce vibration. I've sharpened lots of blades. It takes a pretty good nick on one side to throw a blade off. I would be willing to bet that there is a great number of mowers out there with nicked and gouged blades that have been running like that for years. The mowers just keep running. I certainly don't sweat balancing a blade if it looks good to me.

However, those who don't have much practice or skill should balance their blades until they feel they're good enough at sharpening them.

I'll tell you this much. A lawnmower blade is far less sensitive to imbalanced sharpening than a chainsaw chain. Now that takes skill and discipline if done free hand.

 

[yeehaw1960]

My grinder is about worn out. I have one just like it under some junk that's on top of some other junk waiting for it's day to come. Just make sure you don't bare down too hard when making cuts. Several passes on each side until you have the desired edge is better than getting there with a couple hard passes. You can take the (little there is) temper out of a blade by grinding too hard. I bought one of those useless little balancers some years ago and threw it out after a few sharpenings. The old nail in the wall is close enough (actually very close). For the star blades, there's a way to put them on the nail to check for balance. Look at it for a moment and it will come to you. The shop down the street actually sharpens blades with a hand held grinder. I just use the zen blade method...I am one with the blade...I am one with the blade! I have a stiff wire wheel on the other side of the grinder to knock off any burr.

 

[Shannow]

Originally Posted By: nitehawk55
BTW , "eyeing" a blade cannot in any way tell you if it is balanced and grass clippings that stick to the blade have little effect on the balance . If you run blades that vibrate it will take out bearings in a deck hub or cause wear at the crank/block on a push mower engine . Any small variation in balance will cause vibration , small amounts you may not feel but it's the same as having a tire on your car a bit out of balance .


It takes pretty big amounts of metal off to bring a machine to an ISO standard of "Don't Run", or even "Run, but for not very long".

 

[nitehawk55]

In any case just take the time to balance your blades , better to know they are than the issues it may cause .
I'm experienced and I still balance as it only takes a few to do it .

I operated a dealer/repair shop for many years and also worked in the tech dept. at Stihl Canada for 17 years .

 

[bigmike]

I must be either lazy or uninformed. Probably a combination!

I never sharpen and hardly ever replace a blade, so what am I supposed to see as a benefit to doing so?

I mow most of the year with my Toro walk behind. I replaced the blade at 3 years, but only because it was in the shop having the transmission fixed. I figured what's another $20?

I mow mostly St. Augustine and bahia grass, if that makes any difference. Roughly 1/4 acre.