Sharpening mower blades

[Machinery Poor]

Looking for a blade sharpener that will do the Ventrac blades. Ventrac sharpens about 10" of blade on each end and most blades sharpeners will only do about 6". Oregon has an "extended" sharpener but it runs about $650 not including tax and shipping. Anyone know of any machines that will do Ventrac blades? I prefer not to use angle grinder, files, etc. is Oregon the only choice?

 

[LD1]

No experience with blade sharpeners, but curious what you have against angle grinders?

 

[Machinery Poor]

No experience with blade sharpeners, but curious what you have against angle grinders?

Nothing against angle grinders, I can't seem to maintain an accurate angle with one.

 

[oosik]

Angle grinders & ******* files is all I've ever used to sharpen my mower blades. The exact angle of the grind and razor sharpness is not rocket science nor is it required. Same blades & sharpening method have been used on my mower for the last eight years. Grass gets cut just fine.

 

[Ed of all trades]

I have a Belsaw that will do what you want. Not sure of the price now. Ed

 

[rswyan]

I'm with oosik on this one.

I was thinking of making up a jig using precision ground rod and plastic bearings that was angle adjustable that I could mount an angle grinder in/on, with the grinder sliding along the rods at an angle, to sharpen mower blades ... but the more I use an angle grinder freehand, the less I am inclined to believe I need it. Just follow what's already there ... I use a Type II snagging wheel for the rough cut and then finish with a flap disc.

 

[Sawyer Rob]

$650.00 will buy a LOT of new blades!!

I use a bench grinder and it does a GREAT job...

SR

 

[pmsmechanic]

I always change the angle on my blades when I sharpen them as I don't consider the angle to be critical. I also add a small bevel on the bottom of the blade as it saves removing a lot of metal to get a sharp edge. I sharpen about three times and buy new blades as the ends are rounded off enough so that there isn't sufficient material left to grind to an edge.

I remove the blades form the mower and remove the dried up grass. I hold the blades in my vice and sharpen them. I check that they are balanced and then reinstall. I hate mowing with blades that vibrate.

 

[kthompson]

For me the best tool I have used is large belt sander. You can sharpen the length you have just by the angle you turn the blade on the belt. (I am talking about you may have to position your blade at 45% to the running belt). Now I use a wood flat bed belt sander, a Craftsman you may find used in wood worker shops. Think it is a 6 inch wide belt. User a med or so wood belt and it has worked well for me. Easy to see what is going on, does not grab the blade from you and it if you want to hold at certain angle should be easy to make one setup to for lost cost. I find it is easy to feel you are the angle of the blade is ground already.

 

[Gary Fowler]

Maybe it is just because I have thousands of hours of using an angle grinder, but I don't find it hard to maintain the angle when grinding. I started out in construction as a helper and that required using the angle grinder to bevel pipe at a 37 +or - 5 degree angle and both pipes when joined together had to be the same for the best welding conditions. Pretty soon you get good enough that all the bevels are exactly the same.

I sure wouldn't spend any money on a machine cut a bevel when with just a few hours of experience you can keep the bevels exact. Bevel angle is not critical for a mower blade, just try to keep both ends exactly alike.

I like to use the sanding disc for sharpening. They are a bit slower but more forgiving in gouging out the metal if you make a slip plus they don't heat up the blade metal as much as a solid carborundum disc.

I sharpen my blades about every 3 mowing due to all the rocks and crawfish mounds in my yard. I find that frequent sharpening doesn't require the massive removal of metal like it does when the blades get really dull (cutting edge about as thick as the blade) and keeping a sharp blade reduces the power needed to turn it AND makes for a neater looking lawn.
I use my tractor to lift the mower up so I can remove the blades and clean under the deck. An impact gun makes quick work of the bolts. I keep a spare set of blades sharpened all the time so I can change the blades in less than 5 minutes after I get it lifted up. Sometimes cleaning under the deck takes much longer than replacing the blades to remove all the mud adhering from splattered crawfish mounds.

 

[LD1]

I prefer my angle grinder.

1. as others said, it aint rocket science
2. I already have many

I would hate to buy a $650 tool for the sole purpose of sharpening mower blades....unless I owned a mowing business and had many mowers.

 

[the old grind]

I'm with oosik, too. Clamp blade in vise or similar with the edge up. Hold the AG firmly with your arms and rock your body to go across the cutting edge. This will help you maintain a consistent angle, whatever you choose.

Don't be concerned with 'facets' when grinding. Don't try to remove every nick, either, they'll clean up on a successive re-sharpen.

Balancing the blade is most important to reduce vibration and wear & tear on spindles. Edge quality (sharpness) is secondary, and only on the first cutting after sharpening are blades razor sharp. Keep it simple, and mow 'tall'. :thumbsup:

tog
(journeyman toolmaker/tool grinder, ret'd)

 

[prs]

I have large belt sander intended for wood working. The bed or platen can be set from angled down to fat to straight up. With the bed set horizontal and with metal sanding aggressive belt in place it makes short work of getting blades razor sharp without over heating and keeping original bevel for full depth of cutting edge. I figured the belt would ruin quickly with tool steel blades, but I have used it for years with same belt and I sharpen about every 25 hours of use. It will do normal and left hand blades with same ease. Mine takes common 8" X 48" belts. I balance on a NoMar motorcycle wheel balance stand, the rod fits the Ventrac holes perfectly. And a tip in general, when I sharpen the blades are razor sharp, but if I use them that way the edge peens back and dulls quickly, but if take a medium carborundum axe stone and hand rub the razor edge at 90 degrees in circular motion very lightly to soften that razor edge, they cut just as well much longer.

prs

 

[jcummins]

Burr King x4 Mower Blade Sharpening - YouTube

But no way I buy one of those, unless I was in the business of sharpening blaes.

 

[PhysAssist]

I have always used an angle grinder, because that was easier for me than the small 6" bench grinder that I had used before that, and putting the blade into a vice was part of the why it was easier.

For the past couple of years, I have been using my small [compared to KThompson and PRS's monsters @ 4" x 36"] HF belt sander with a 60 grit Zirconia belt.

The sander has just enough platen for me to sharpen my blades and with the belt laid flat, and oriented that way, maintaining the angle is really easy.

A hint my old man gave me a long long time ago: If you get the edges sharpened to where you want/need them, and then find out that one end is heavier than the other, don't regrind the edge, just grind a little off either the flat [non-edge] corner or the flat edge of the heavy end.

Thomas

 

[pmsmechanic]

Sometimes cleaning under the deck takes much longer than replacing the blades to remove all the mud adhering from splattered crawfish mounds.

I find that mowing the grass when it's damp makes the grass stick to the deck really well. So I mow either on the dew or when the grass is bone dry. The best is just after or during a rain. The water droplets wash everything off.

 

[prs]

I have always used an angle grinder, because that was easier for me than the small 6" bench grinder that I had used before that, and putting the blade into a vice was part of the why it was easier.

For the past couple of years, I have been using my small [compared to KThompson and PRS's monsters @ 4" x 36"] HF belt sander with a 60 grit Zirconia belt.

Thomas

I was trying to think of what kind of abrasive and what grit grade the belts are; same as you say. I would not pay the new price for the machine either and mine is so old (1969) when I was more into wood working. I also do as you explained about having the platen flat and holding the blade by hand at correct angle, its easy peasy.

I check balance before sharpening so if one end is a bit heavy, I go ahead and give it an extra pass or two across the belt. Then check balance again after the fact. My first step is to remove all organic build-up on the blades and then use a mill file to remove any nicks on the flat side by running the file on the flat -- NO bevel there.

prs

 

[PhysAssist]

I was trying to think of what kind of abrasive and what grit grade the belts are; same as you say. I would not pay the new price for the machine either and mine is so old (1969) when I was more into wood working. I also do as you explained about having the platen flat and holding the blade by hand at correct angle, its easy peasy.

I check balance before sharpening so if one end is a bit heavy, I go ahead and give it an extra pass or two across the belt. Then check balance again after the fact. My first step is to remove all organic build-up on the blades and then use a mill file to remove any nicks on the flat side by running the file on the flat -- NO bevel there.

prs

Great clarification and description, I need to go back to the file.

My SWMBO has been mowing more often than I have because of my work hours, and she has a real knack for finding the hidden rocks [usually more like boulders], so there have been a lot more [and a lot bigger] dings in our blades.

While I'm not at all committed to a pristine lawn [our "yard" is more like clearings between the trees, and we have a lot of areas where it's more broadleaf than grass, having a set of spare blades sharpened and ready to pop on seems like a great idea.

Thanks,
Thomas

PS: I might start looking on CL for a big old used belt machine in addition to my other regular local searches.

 

[TNMark1]

I flip the mower up and lightly dress them with an angle grinder that was about $20 at Harbor Freight... Takes a couple minutes every 20 hours or so..

Mark H

 

[Ford850]

I buy a second set of blades, and sharpen them when I have time, so that spare set is always ready to swap out when the set in use gets dull. Then install the sharp set and toss the dull blades on the bench to be sharpened on a rainy day.
I clean the blades with a putty knife and/or wire brush before sharpening. It's worth the couple minutes and makes it easier to sharpen and balance.
I've settled on the flap disk in an angle grinder, with the coarsest grit I can find. They sharpen fast, remain cool, and leave an excellent edge. I lightly hit the full angled edge a couple passes, then add a quick steeper angle to sharpen just the edge. That steeper angle stays sharp longer and allows me to have more blade life by taking less off while sharpening. I don't avoid sticks and limbs, actually I try to mow them to chop up and clean my deck.
This year I bought an extra angle grinder from HF to use as my dedicated blade sharpener. That way I can leave the flap disk on and it's ready to go on those rainy days. I used to hate sharpening blades, but now it's enjoyable and only takes minutes to clean and sharpen 6 blades.