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Basic Blade Sharpening Skills

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I've taken my main lawn deck out to maintain. I scrapped and painted the bottom avoiding where the bearings are (I didn't take the time to tape off. This is a working deck. Anyways, I'm looking to sharpen the blades and I am looking for the tips/advise I need to do this. First I have already briefly filed these on the deck, but I have not taken these off yet. My assumptions are that I will take these off and really give them a good file job and at the same time make sure they stay balanced in the middle. Is there any other tips or advise I should be aware of? Is it just better to bring them to a lawn mower shop? Or should I just break down and buy new? Thank you in advance for any advise on this mater. I'd also appreciate any recommended links within this site on this subject.

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RayS
I sharpen my at work on a stationary belt sander seems to work the best for me. Lawn mower shops also to a great job and usually only charge 2 to 3 dollars a blade. But filing them also works great.

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JoeJ
;)I us one of my angle head grinders. But put on a sanding pad. I still balance with the nail in the side of the workbench and so far never a problem. I would be interested in any feedback from those with the little bubble balancers, for mower blades.

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D-17_Dave
I've always used a side or bench grinder. Had real good luck. I always grind plenty off to get down to a clean smooth edge on the bottom of the blade, and a 30-45 degree angle on the top. I may be guilty of some oversharpening, but I feel the blades cut much cleaner, and take far less HP to cut like this. So I am qiucker on my job and easyer on the tractor by doing tis. I have a lot of uneven yard, with a mix of grass, weed, and whatever else pops up, so this ensures me a cleaner look when I'm done. Also I don't sharpen everytime. I just keep an eye on the blades and hit them when nessasery. Father-in-law buys a new set every year, puts them on a 60" deck behind his Ford tractor and never looks back. Wonders why his yard looks ragged from mide summer on. I metioned to him he might want to sharpen them blades once in awhile but he just laughed and said his blades were made of too high a quelity steel and never needed sharpning. Another time I just smiled and walked away.

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sandyhillbill
a common mistake (imho) is to get the blades too sharp. I agree they need to have a clean smooth edge but the sharper the edge the faster it dulls. and if the mower is a belt driven multi-blade deck balance is not real critical. granted you wouldn't want to take more off one end than the other so you could tell it with the nacked eye. Again this is my opinion.

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sandyhillbill
I left out the most important part on my previous reply --BE CAREFUL-- those blades can be very dangerous when sharpened and you are putting them back on. Safest way I have found is impact wrench-- whether pnuematic, electric corded or battery powered. again BE CAREFUL-- never happened to me but friend slipped and cut gash in wrist that required several stitches.

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Agricola
Take off equal amounts from each side of the blade. Don't be too frugal. When the blades starts to get too narrow, buy new ones. Blades aren't too expensive, legs are. Balance them on a nail or a blade balancing tool. I balance with one side up and then turn it over and balance it with the other side on top. I personally think the curve made by the bench grinder makes for a nicer edge. I don't typically like a flat edge. Just my views

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Boney
Some of you may find it hard to believe { lol lol lol}with my perfect spellling but I did not write this I cut and pastted it. HOW TO: Sharpen rotary mower blades By Donald C. Wineland, Stens Power Equipment Parts Grounds Maintenance, May 1, 2002 Print-friendly format E-mail this information There is no technical mystery to sharpening a lawnmower blade. It just takes common sense and a bit of know-how. If you have a good bench grinder or a professional blade grinder, you can do a professional job. Remove the blade Removing the blade can sometimes be the hardest part of the job. A good way to start is to squirt some penetrating oil on the blade bolt and nut and let it stand for a few minutes. While you are waiting, pull the spark plug wire to make sure the mower does not accidentally start. I have talked to some people who had stitches in their hands or even a few missing fingers because the engine fired unexpectedly. Next, block the blade so that it does not turn while you are removing the blade nut. A blade holder will make this easy. However, if you do not have one, a block of wood under the deck and a C-clamp will do the job. Once the blade is removed, use a scraper to remove excess grass build up around the center hole of the blade. This will ensure a good, tight fit and assists in keeping the mounting bolt from working loose. Sharpen the blade Now that you have removed the blade, it's time for sharpening. The primary goal is to consistently maintain the correct angle on the blade. Manufacturers perform hours of testing to determine the angle that will give the user the best cut with the longest span of time between sharpening. It's important to keep the angle as it was intended. Around 40 degrees is typical, but this can vary, so check with the blade manufacturer to obtain the exact figure. A narrower angle, such as that of a pocketknife, will cut well initially, but will dull quickly and nick easily. On the other hand, a blade with a less severe (more blunt) angle will not provide the same quality of cut, even though it might wear more slowly. Blades come from the manufacturer with a milled edge. Milled edges are the best, but machines that provide a milled edge are expensive. You still can do a good job with a professional blade grinder. A sharpener with a grinding wheel is not preferred, because it will give you a hollow grind. As you sharpen, move the blade back and forth across the grinder, maintaining the proper angle until you get the edge you need. Do not force the blade into the grinder. Forcing the blade to grind faster heats the blade and will bein cause the metal to lose its temper (hardness of the blade). Some mechanics will keep a bucket of water handy and will dip the blade in it to cool. If the blade turns a straw color while grinding, it's too hot and the temper is likely gone. Check for balance and straightness It is not necessary to grind a blade until all nicks are out. Grind until you have a sharp edge on the blade in the area where there are no nicks. A blade with numerous nicks should be replaced, but a few can be tolerated. Try to grind both edges of the blade evenly, removing the same amount of metal from both ends. This is important when you check the balance. An inexpensive cone-shaped blade balancer can do an excellent job. Wall-mounted blade balances are also available. These help you see if the blade is straight. An out-of-balance or bent blade can cause severe vibration and damage to your equipment. You can balance a blade by grinding just a little more metal off the heavy end of the blade. However, never try to straighten a severely bent blade. Straightening it could cause a weakened or cracked blade. A cracked blade could break apart when turning at the high RPMs under the deck. The potential liability or injury is not worth the cost of a replacement blade. Remount the blade Once you have finished balancing the blade and checking it for straightness, clean any burrs or jagged edges with a metal file. Now it's time to put the blade back on the mower deck. Remember you now have a very sharp blade. Use extreme caution when installing. Donald C. Wineland is a product consultant for Stens Power Equipment Parts, a division of Ariens Company. www.stens.com; 800-457-7444.

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Salthart
Another thing I always try to look for is wear where the lift wing turns up. If you cut close or if you have sandy soil the sand can dig pits where the wing turns up. A great many times I have removed blades for someone and found the lift wings to be gone.And they don't wear down, They are cut off right where the rise starts. Question is, Where were their legs or the kids next door etc when it did turn loose ? Few guns fire a bullet much faster and dang few run a bullet that heavy that fast. The same attention should be given to the mounting hardware and blade adapters. I know all this is re-hash for most of you but for the sake of those that maybe don't know I thought i'd add this here. As to how sharp ? THe ground you mow should tell you. If you "Grow" rocks like I do and or you cut the garden and whatever else happens to need cutting I would go with a more steep edge so as to have more steel on the leading edge. Smooth ground with a nice carpet of grass will look far better with a very sharp edge. And for those of you out there with Johnson grass, LOL sharp blades will save you a good deal on engine strain ! As to balance, Show me a man with a blade that is a pennys weight out of balance at the start of the season, and I'll show you a man who will be buying bearings etc before the season is out.. Don't think so ? Ask you favorite auto mechanic what leaving one tiny lock washer off a torque converter bolt will do to a V-8. something to think about.. Just my 2 cents worth...

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BigSix
Cone Balancers I use one of the inexpensive "cone" balancer-$3.00 or $4.00. There's no bubble--it just stands up straight when the blade is balances. I've used a couple of them and it's good to flip the blade to double check the balance, as Agricola states. One of my balancers always lists slightly to one side when empty, but I work around that. The biggest problem with the cone-style balancer is that it is "terraced" with successfully-larger diameter ridges to set the blade centerhole on. However, often the fit between the blade hole and the cone's "ledge gradations" is poor. I just try to center the blade on the closest-sized ledge, by eye, and it works pretty well, but adds to the time spent. If you have blade that fits closely to one of the cone's size gradations, it's significantly faster.

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hufhouse
I have tried both the bench grinder and my 4-1/2" angle grinder with coarse grit paper. I much prefer the small angle grinder, because I can control it so much better and the blade doesn't overheat. I can't seem to get the hang of using the bench grinder. It just chews metal off too fast and I can't control the angle of the blade as well. It might be a good idea to take your blades to a shop and have them sharpened once every year or two, and then use the angle grinder to touch them up in between. They come back from the shop with a beautiful edge.

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powerking_one
My blade balance solution is a "poor man's" version of a commercial Magna-Matic type precision balancer. For your blades's particular center hole I.D., get a ball bearing matching it (non-sealed or shielded is best, or you can remove the seals/shields) and with appropriate diameter spacers and say a lag bolt and washers, attach it to a verticle stud in the garage or shop. Use solvent or carb cleaner to remove any dirt or heavy grease from the races which would cause extra stiction. Then re-lub the race with light machine oil so the bearing free-wheels nicely. I would also add to the Sten's article, to completely scrape all grass ,chaff and debris off before sharpening. It can affect the balancing. Tom (PK)

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