Craftsman Tractor Blades

[dougbthom]

Just purchased new blades for my Craftsman Tractor. My question is should the new blades have quite a sharpe cutting edge from new? The reason I ask is that these new blades have a fairly blunt cutting edge. Do I have to sharpen them somewhat myself before using? Thanks

 

[KennyG]

Mower blades should have the approximate sharpness of a butter knife. You can sharpen them more, but they will dull to the "butter knife" profile very quickly.

 

[dougbthom]

Thanks for the input. These blades are much blunter than the butter knife edge you refer to. I will likely give them a try once our lawn dries up enough. I may end up having to give them somewhat of a sharpening.

 

[mddorange]

:welcome:
To the TBN forum Dougbthom. Glad you joined us here. The blades used on my Craftsman riding mower have always been dull even if I get them from Sears with the Craftsman name on them or elsewhere with the actual OEM name on them.

 

[dougbthom]

Thanks for the welcome. Do you normally sharpen up the new blades before you use them? That's the point I'm at now. A fellow at the place where I purchased the new blades told me that it's not a good thing to have the blades razor sharpe as they will do damage to the lawn!

 

[DT86]

A fellow at the place where I purchased the new blades told me that it's not a good thing to have the blades razor sharpe as they will do damage to the lawn!

I need to have this explained to me.

Super dull blade tears the leaf instead of slices, leaving a shaggy cut and brown tips. Too sharp will just become dull again quick, as mentioned previously above, but "damage the lawn"?

 

[CCWKen]

Yeah, the "fellow at the place" has it backwards. I keep all my blades sharp, even the rotary cutter and flail. Makes for a nicer cut and takes less power. I can tell right away when the ZTR blades are getting dull. I start smelling burning rubber belts and hear the engine struggling in high grass.

You wouldn't dare run your finger along the edges of my blades. But... I don't sharpen mine like a knife; more like a chisel. The bottom side always stays flat.

 

[KennyG]

I keep all my blades sharp, even the rotary cutter and flail. Makes for a nicer cut and takes less power.

But... I don't sharpen mine like a knife; more like a chisel. The bottom side always stays flat.

We could really start a long discussion here. I've always heard that rotary cutter blades should be kept dull, so they "batter and shatter" the larger plants. Leaves less chance they will puncture a tire or foot and makes them less likely to sprout again. Not sure it's all that important one way or another.

Definitely agree to sharpen only one side. I only do the bottom side after I hit a rock or something.

 

[CCWKen]

Yeah, I agree but I mostly cut high grass and weeds with my rotary. Any shrubs or low/broken branches on Mesquite trees still get turned it chips. 80-90% of what I keep cut is open field so a sharp blade works better for me. Whatever works best for you should be used.

 

[Midniteoyl]

This is from John Deere:

A narrower cutting edge can be damaged more easily and will get more nicks during use. When finished, the blade should have a 1/64 inch (.40mm) cutting edge.

Answer

 

[CCWKen]

Perhaps John Deere steel needs a thicker edge to keep from nicking.

 

[Midniteoyl]

Perhaps John Deere steel needs a thicker edge to keep from nicking.

Gator blades are 30degrees with a .030mm (1/32) edge.

 

[dougbthom]

I changed to new blades (Oregon) I think they're called. Didn't make a lot of difference from the old blades which were about a year old. I'm getting some uneven cutting even after I checked to see that the deck was level. My manual says to have the wheels that are under the deck "just off the ground" while in the cutting height and on level ground. I set the wheels down from where they were and now I can barely get my index finger under each of the wheels. My thinking is that maybe the wheels are too close to the ground and not allowing the deck enough movement to make up for uneven ground in spots. What are your thoughts please?

 

[BoylermanCT]

I changed to new blades (Oregon) I think they're called. Didn't make a lot of difference from the old blades which were about a year old. I'm getting some uneven cutting even after I checked to see that the deck was level. My manual says to have the wheels that are under the deck "just off the ground" while in the cutting height and on level ground. I set the wheels down from where they were and now I can barely get my index finger under each of the wheels. My thinking is that maybe the wheels are too close to the ground and not allowing the deck enough movement to make up for uneven ground in spots. What are your thoughts please?

As long as the wheels are not touching the ground when you are parked you are OK. They should only touch ground when the mower rocks or dips while moving. Are the new blades perfectly flat along the cutting edge? I recently bought blades that had a small warp in them. I hammered it flat and they cut smooth again.

 

[dougbthom]

Thanks for the reply. Yes the blades seem flat. I took them off a "slightly" sharpened them as they were more than butter knife in thickness. I take it that the only part you sharpen as at the tips and sharpen only the bottom side of the blades. Tomorrow I'll try setting the wheels up one notch to give the deck a bit more play and see if that helps. It's very difficult to get under the deck and measure from the ground to the blades to see if they are the same distance on each side but they appear to be and in measuring the deck frame on each side to the ground are dead on if that makes sense.

 

[BoylermanCT]

You can sharpen more of the blade but it may put greater load on the engine since you are increasing the cutting surface. I don't think it would be worth the effort. You should only be sharpening the top side of the blades. Make sure the blades are mounted correctly and not upside down. If one is mounted upside down, you will definitely have an uneven cut.

 

[Midniteoyl]

Thanks for the reply. Yes the blades seem flat. I took them off a "slightly" sharpened them as they were more than butter knife in thickness. I take it that the only part you sharpen as at the tips and sharpen only the bottom side of the blades. Tomorrow I'll try setting the wheels up one notch to give the deck a bit more play and see if that helps. It's very difficult to get under the deck and measure from the ground to the blades to see if they are the same distance on each side but they appear to be and in measuring the deck frame on each side to the ground are dead on if that makes sense.

FYI, no lawn mower blade should be 'knife sharp'. They are meant to be a little dull with a 1/32"-1/64" edge. If they are sharpened to a fine edge, the edge will simply curl and roll back very quickly anyways and result in a edge that could, and usually is, duller than normal. And you should never sharpen the bottom of the blade, only the top and keeping the correct angle. The bottom is to remain flat. Speaking of which, Oregon Gator blades use a 30* angle and a .030" (1/32"/.8mm) edge (what they cal 30-30) as opposed to the 40-45* angle and .015"(1/64"/.4mm) edge of 'normal' blades. This is why the seem to last longer between sharpening and resist dings better.



[video]https://mowhow.mowdirect.co.uk/hc/en-gb/article_attachments/200643788/totorotshrp.gif[/video]

 

[dougbthom]

Over the years, I have always sharpened the top sides of the blades until one of the service people of lawn tractors told me to sharpen only the bottom sides. It does make more sense to sharpen the top sides in my mind at least so I'm going back to what I've done for many years with no problems. Now I have sharpened the bottoms of these brand new blades but hopefully by sharpening the top sides a bit now may straighten this problem out. Thank you both for the very useful info. It's appreciated.

 

[BoylermanCT]

The bottoms of my Oregon Gator blades have a grit welded onto them, so you would not want to sharpen the bottom side. I stopped using mine because the cutting edge is 3/8" lower than my stock blades. The Oregon blades dip down from the spindle and I mow my field on the highest setting, and did not want to go 3/8" lower. I switched to Max Power / Diamondback blades which are completely straight, with no dip.

 

[Midniteoyl]

The bottoms of my Oregon Gator blades have a grit welded onto them, so you would not want to sharpen the bottom side. I stopped using mine because the cutting edge is 3/8" lower than my stock blades. The Oregon blades dip down from the spindle and I mow my field on the highest setting, and did not want to go 3/8" lower. I switched to Max Power / Diamondback blades which are completely straight, with no dip.

Unless your OEM blades also had the 3/8" offset, you got the wrong blades.