shop-talk
[Top] [All Lists]

Blade sharpening (was Re: CBs and Lawn Mowers..

To: shop-talk@autox.team.net
Subject: Blade sharpening (was Re: CBs and Lawn Mowers..
From: Mike Sloane <msloane@att.net>
Date: Mon, 13 May 2002 17:58:12 -0400
There is a bit more to sharpening a grass mowing blade that Brian indicated. It 
really is best to periodically remove the blade and touch it up properly with 
the largest grinding wheel you can find. The edge need not be razon sharp, in 
fact, if it is that sharp, the metal will turn over. What you need is about a 
35-45 degree uniform edge. Don't ever take any material away from the end or 
round it off. The reason for the large wheel is to avoid a concave edge from 
the 
diameter of the small wheel. I would say that 6" is the absolute minimum. If 
you 
have an angle grinder like Elton discussed, you want to run the wheel parallel 
with the edge, not across it. And then, if the edge is "feathered", touch it up 
with a fine file or stone.

Balancing the blade is critical - even the slightest out of balance condition 
will cause unwelcome vibration that can tear bearings and seals apart at a 
constant 3600 rpm. The end of the blade is moving at about 5000 feet/second, by 
the way, and that is where most of the cutting gets done. Better than a 
screwdriver would be a thin knife held horizontally, but the best solution is a 
cone that sits on a pointed pin, so that the out of balance blade is free to go 
wherever the weight tells it. I bought mine from a commercial landscaping 
equipment dealer many years ago. The cone is stepped so that the center of the 
blade fits precisely. You should not remove material from the back of the blade 
unless the out of balance is front to back (that happens too), but remove the 
material from the sharpened area only. If the blade becomes so nicked that you 
cannot get a straight edge without removing excessive material, then you need 
to 
replace the blade.

Another caution is cheap blades. The blade that comes with the mower is at 
least 
twice as strong and stiff as the cheap replacement blades sold by the chain 
stores. I have seen cheap blade broken in half or bent like a pretzel from just 
hitting a stick or toy. They also won't hold an edge and dull very quickly. 
Better to buy an OEM replacement from the dealer and have it last for years. I 
am still using the original Snapper blade on a Snapper V-21 walk-behind that I 
bought new in 1972 and the 35-40 year old Woods and IH blades in their 60" 
tractor mounted mowers (and I use them to mow about 5 acres of grass a week 
during the growing season). I sharpen them once a year, if I get a round tuit. 
(those round tuits are hard to find!)

By the way, the last new mower I bought was that Snapper in '72, after that, I 
get them from town clean-up and do a simple "tune up", oil and spark plug 
change 
and then use them or sell them. I don't even bother to bring home the Sears or 
others that came from the discount chain stores (K-mart, Wal-mart, HD, Lowes, 
etc.), as they are not worth even the price of a pint of oil. But I will bring 
home a Toro, Snapper, Husvarna, Honda, etc.

Mike

Elton Clark wrote:
> Brian wrote:
> 
> 
>>I've tried to get my mower blade sharpened here in
>>Fl, for less than the cost of a new one, but sadly,
>>it costs more to sharpen it. I still have two sitting
>>in the garage waiting until I get around to sharpening
>>and balancing them myself, or finding someone who
>>does it cheaper.
> 
> 
> Though I'm seldom an advocate of cheap tools,  here's a application that
> fits: Visit  http://www.homier.com    .  They sell a 4 1/2" 10,000 rpm disc
> grinder complete with a side handle, disc guard, wrenches and disc for $
> 5.95!   I bought one off their truck but they are the same price online.  It
> does everything my high priced Makita does for the chump-change price of 6
> bucks!  Perfect to lay around the house and do sharpening jobs, padlock
> "removal" and amazing chores with the fitting of a sanding wheel or disc.
> One caveat:  I think it's smart to fit a  good Makita or Forney disc . . . I
> feel they are safer (!) at 10,000 RPM.   On a couple of my mowers, I can
> sharpen the blade on-the-mower . . Balance isn't that critical . . . the
> unbalanced load on the blade, doing all it's cutting in a 180 degree arc, is
> far worse than a gram or two of weight on the blade tip.
> Tony Clark
> (free advice and worth every penny!)
> 



-- 
________________________________________________________________

Mike Sloane
Allamuchy NJ
(msloane@att.net)
<http://www.geocities.com/mikesloane>

Letter writing is the only device for combining solitude with good company.
-George Gordon Byron, poet (1788-1824)

///  unsubscribe/change address requests to majordomo@autox.team.net  or try
///  http://www.team.net/mailman/listinfo
///  Archives at http://www.team.net/archive/shop-talk


<Prev in Thread] Current Thread [Next in Thread>
  • Blade sharpening (was Re: CBs and Lawn Mowers.., Mike Sloane <=