Advice on blade sharpening

Discussion in 'Lawn Mowing' started by yardmonkey, Jun 5, 2000.

  1. yardmonkey

    yardmonkey LawnSite Senior Member
    Posts: 340

    I would like to glean some knowledge on the subject of blade sharpening from all you experts. I have read some posts discussing<br>dedicated blade sharpening machines (I assume<br>these are specifically for lawn mower blades?) which cost around $400.00. That's a<br>little high end for me right now. I'm just<br>getting started and have just one 21&quot; mower.<br>I also have read that mower blades can be<br>sharpened with a file. I tried that and didn't get too far. It seems like it would take a long time and a lot of energy.<br>I took my blades to the dealer where I bought<br>my Honda. It has two blades - you add a mulching blade to the regular blade to make<br>the Hondas into mulchers. I asked if they could show me how they sharpen blades so I<br>could learn. They said they couldn't let me into the back for insurance reasons. Well the<br>door was open so I watched. The blades were<br>handed to a mechanic. He clamped one in a vise and hit each side real quickly just 2 or 3 times with a handheld grinder. He put the<br>next blade in and it went flying when he hit<br>it with the grinder (he clamped them in <br>horizontally). He clamped it back in and<br>hit it a few times with the grinder. It probably took him a minute or two to do both<br>blades. He handed them back to a saleperson<br>who brought them to the front. They sell those little round blade balancers, there were some right on the counter, so I put the<br>blades on it. One of the blades titlted down<br>quite a bit (maybe touching the counter). I said, &quot;Is this something I should be concerned with?&quot; He says, &quot;Oh, that counter is not completely level and he already balanced the blades&quot;. Actually this was the<br>owner of the place. Also the blades didn't<br>seem too sharp. So, I'm thinking that having<br>someone else sharpen the blades for me is not<br>the best option. I went to buy a grinder and<br>the guy at the hardware store talked me into<br>a bench grinder instead. This seemed much <br>cheaper, since I may also need to get a big vice with the handheld grinder. But then<br>another guy in the store showed me a little<br>bit that goes on a regular drill so I just<br>got that ($3.00). I only used it once on<br>the blade on my crummy Sears mower but it<br>seemed like it wasn't quite what I needed.<br>So, anyway, I'm wondering what people think<br>about using a handheld grinder versus a bench grinder for sharpening mower blades?<br>Or are these the options I should be<br>considering? And would you clamp a blade in a vise horizontally?<br>Also, a blade should really be sharp after<br>its sharpened, shouldn't it? I mean after<br>the store sharpened these blades, they were<br>less dull, but I wouldn't say they were sharp. How sharp should a mower blade be and<br>how much difference does a sharp blade make?<br>I know these might seem like dumb questions,<br>but any advice would be appreciated.<br>It could be really cool if there were some<br>FAQs here with some basic info on stuff like<br>this for new guys.<p><p><p><p><br>
  2. HOMER

    HOMER LawnSite Gold Member
    Posts: 3,183

    Sharp blades are very important, they determine whether you &quot;cut&quot; the blade of grass or you &quot;beat&quot; the blade into submission. A blade should be very sharp right after it's sharpened, at least mine are just as sharp as I can get them. I use a bench grinder and do a pretty fair job if I must say so. Hold the blade firmly and try to duplicate the same angle that it came with and sharpen it until your fully satisfied it would do as much damage as Billy Bob did to Dwight. Your dealer didn't do you any favors and next time you go in there tell him the mower has sheared all the bolts due to the vibration from an unbalanced blade. No it should not touch the counter, yes it should be sharp, no you don't have to buy a $400.00 machine to get one sharp, yes a hand grinder will do but then you really need a vice. But one of the el-cheapo blade balancers or hang it on a nail, you'll know if one side is heavy.<p>Hope I helped!<p>Homer
  3. scottlawns

    scottlawns Guest
    Posts: 0

    i bought mine at Lesco for $320.00 and it works should sharpen your blades every nite if you can,,it makes a big differnce and you can cut faster without missing any grass.
  4. yardmonkey

    yardmonkey LawnSite Senior Member
    Posts: 340

    Yes, mucho helpful, thanks.<br>I will probably get a bench grinder.<br>I wondered about having to hold the blade up <br>to it and the guy in the hardware store showed me that there was a little stand in<br>front of each wheel. Do you prop the blade<br>(or your hand) on something or just hold it up to the wheel? Probably you're wearing gloves? And I wonder if you are using the bench grinder because that's just what you have or would you prefer it over a handheld grinder?<br>Been meaning to watch Slingblade again, too.<br>..mmmm hmmm..<br>
  5. Toroguy

    Toroguy LawnSite Bronze Member
    Posts: 1,075

    Yardmonkey,<br>I use a bench grinder also, Delta from Home depot. I mainly use it after I hit something that nicks the blade. And the wire brush to remove the &quot;green&quot; to make sure balance is OK. A decent blade only requires about twenty scrapes with a file, and keeps the angle better than my grinder.<p>The counter was not level...ha I would stay out of there. The employees are not on the level.<p>Before you buy a bunch of blades for a 21' that you will outgrow, check out what everyone started out with on the Who? Where? What? post.
  6. Eric ELM

    Eric ELM Husband, Father, Friend, Angel
    Posts: 4,831

    I started out with a vise and hand grinder. I mounted the vise on the front corner of the trailer and sharpened them there. Since I got the RBG grinder, I still have the vise on the trailer. It's very handy to have on the job for clamping things down if needed.<p>----------<br>&lt;a href=&quot;;&gt;Eric@ELM&lt;/a&gt;<br>
  7. southside

    southside LawnSite Senior Member
    Posts: 790

    Why sharpen 21&quot; blades,all we do is throw them outas they go dull.If you must sharpen<br>then I believe a 4&quot;grinder is the quickest<br>way.But why bother? 21&quot; blades are cheap.<p>Karl<br>
  8. lawn and stump

    lawn and stump LawnSite Member
    Posts: 191

    I have a cedar post with a hole cut diagnaly [i plunged a chainsaw in to cut a hole that the blade wedges into ] just outside the shop door and use a big disk grinder a 2 hp I think, this takes off the material so fast the blade doesn't heat up and take take the temper out and all the mess is out of my shop -- phil
  9. geogunn

    geogunn LawnSite Gold Member
    from TN
    Posts: 3,010

    I use combinations of a large coarse flat bastard file, delta grinder with both wire wheel and grinder wheel and a &quot;mini die grinder&quot;.<p>if the blade is not in bad shape the file does the trick. remember to file into the sharp end of the blade. sometimes the blade even stays on the machine. if the blade comes off the mower I clamp it to the trailer with a C clamp. works perfect.<p>I don't use the 10 inch delta much because I have trouble seeing the grind as it's happening. kind of hard to hold the blade to the wheel at the right angle. I wish I could find a jig that you use with a bench grinder, but I've never heard of one.<p>my favorite method of keeping blades in shape is an air powered mini die grinder. it's very easy to shape up a beat up blade and keep the original angle.<p>for the guys that stress sharp blades--believe them and keep them balanced. it makes a difference.<p>good luck,<p>GEO
  10. BFreiburger

    BFreiburger LawnSite Member
    Posts: 24

    I have had good luck using a Belt sander with 3&quot; by 18&quot; 100 grit belts. I clamp a 3 foot long piece of 1 1/2 by 1 1/2 angle iron in my vice so that the &quot;v&quot; is down, I use the pipe grips that are on my vice. I lay the blade in the valley and clamp it in with welders vice grips. The resulting angle to sharpen is level with the table top and I just buff down the edge with the sander. I make sure to make the same number of passes on both sides of the blade. Make sure you sand from the top down to the edge. The blade does not get hot and not alot of material is removed if you press lightly. The blades come out very sharp.<p>Cost for the belt sander was $50. Angle iron if you don't have a piece laying around $4 Good belts cost about $2 a piece. I have sharpened a three blade Dixie Chopper 3 times still on the first belt.<p>I do use a angle grinder to dress out the nasty nicks that some times happen.<p><p><p>----------<br>Bill @ A Easy Lawn<br>

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