Anyone ever us a Rotex to sharpen Lawn Mower Blades?

ezdrive

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Jan 17, 2008
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Doing my annual yard equipment maintenance and thought about sharpening the blades on my commercial mower.  A grinder makes a mess and the result looks very unprofessional.  I removed the blades and clamped them to a work bench.  Using a 40 grit sanding disk worked great!  No heat buildup and minimal sparks.  I was able to cut a nice even bevel that looked like it was done on a professional lawnmower blade sharpener.  Now I use my Rotex to Sand, Polish, Buff and Sharpen.  Great tool! ::)
 
Is a great tool and a great application.  I would have thought that 40 is too rough to finish with. Have you considered running thru to 120 or so.
 
Excellent point!  I used the 40 Grit to dress the badly damaged blades.  The process includes rough cutting on the flat side of the blade then sharpening on the bevel side.  The blades are then checked for balance by placing on a metal cone through the spindle hole.  Balance is acheived by taking material off the ends.  The 40 Grit does leave a slight burr, so I finished up the process with a light use of a 120 Grit.

The big issue with sharpening lawnmower blade is not to over heat the metal.  I originally thought about connecting the vacuum in the reverse "blower" direction to air cool the blade while sharpening.  This proved not to be necessary.  I should mention that unless you have a spark arrester attached to the vacuum, I would not use the vacuum in this application.  Too high a risk of fire.  Thanks for you positive comments and suggestions.
 
EZ,  Thanks I'm gonna try that.  I use a bench grinder and agree that it looks like hell when I'm done.  What kind of 40 grit paper do you use?
 
Good timing on this post. I will be sharpening up mine using your suggestions in the near future.

Charles
 
I would be cautious about using a dust extractor while grinding metal.  If a hot spark gets into the paper bag and there is sawdust already there, plus an ample airflow - FIRE!  [eek]  I would guess that using the dirt trap for wet operation with a little water in it would be okay.
 
I use my RAS for this job. It works very well and does not burn the blades like an angle grinder would. Never thought about using the Rotex. If you have both tools I think the RAS would be the better tool but I do think it's cool that the Rotex is capable as well.
 

The big issue with sharpening lawnmower blade is not to over heat the metal.  I originally thought about connecting the vacuum in the reverse "blower" direction to air cool the blade while sharpening.  This proved not to be necessary.  I should mention that unless you have a spark arrester attached to the vacuum, I would not use the vacuum in this application.  Too high a risk of fire.  Thanks for you positive comments and suggestions.


A little bit off subject. The other day I was routing out Russian Birch plywood 3/4 inch using 1/2 inch bit, 1400 with CT22 and MFS. I was creating a round mirror frame  with a 30 inch interior groove to receive the mirror. I was taking off 3 mm of material at each pass so not to overheat the bit. I was finishing the second pass when I notice the saw dust left in the groove was smoking in one spot. I lifted with my glove hand the dust and there was a 2-3 mm piece of  material burning like hot coals.

I was wondering if anybody had this experience before, would it have started a fire in the CT22 bag and what is a spark arrestor for vaccum.

Bruce
 
I've used the rotex old shoe cleaning blocks - made from metal... Used it on Gates and when I'm using a filling knife and forget to clean it in the evening... The rotex comes out and cleans it up just fine...

As yet, not tried it to exfoliate my face yet...
 
what is a spark arrestor for

It's a metal device that goes between the hose and CT inlet. It has a baffle in it to knock down hot metallic bits, which fall into the bottom of it.

It is also useful if you're vacuuming up chunks of something hard like mortar. Those chips will also fall to the bottom of it rather than trying to go through the back of the bag.

Tom
 
And one other thing: it is easy to throw the blade out of balance when sharpening. I use a funnel upside down to serve as a balance point. Lawnmower makes a considerable better noise when the two are balanced.
 
While I haven't used it for mower blades, I have used my Rotex and Brilliant paper to sharpen axes, shovels, etc.  Works really well, especially if you don't let them get in too bad  a shape. 
 
Y'all are nuts.

A mill file and a stone are all that I use for lawn mower blades and axes.

The gransfors axe stone that Lee Valley sells is good.  You can go higher grit but mowers and axes are not fine finishing tools and hence don't need a mirror polished edge.
 
Tim Sproul said:
Y'all are nuts.

.....

You can go higher grit but mowers and axes are not fine finishing tools and hence don't need a mirror polished edge.

Rotex + Saphir paper doesn't exactly deliver a 'mirror polished edge'.
 
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