Mower Deck Blade Alignment

[Lloyd_E]

I took off the blades on my 52" mower to sharpen and didn't note positioning. Does it matter how they are aligned when I put them back on? Should they all be oriented differently, all aligned etc?

Lloyd

 

[bczoom]

As far as I know, it doesn't matter.

 

[Spiffy]

If you have a belt drive between blades [I don't know of any that don't], they'll never stay in one particular alignment too long anyway.

The only thing to watch for: a few brands have "non-round" holes (square or star, etc.) or pins an inch or so away from the arbor hole, if so you want to align these for proper tightening to occur.

Can't resist the obvious: Yes, it is possible to get them on "up-side-down" /forums/images/graemlins/wink.gif

 

[LBrown59]

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Can't resist the obvious: Yes, it is possible to get them on "up-side-down" /forums/images/graemlins/wink.gif )</font>
This will cause the grass to stretch

 

[Egon]

The three blade mowers have the front blade forward so they can't hit each other but overlap on the cutting. And yes they can be reversed on some types.

Egon

 

[millsnhills]

Ok, I took my blades off night before last to sharpen. While mowing it looked like all of the grass was not being cut properly. As I was riding around "honestly" I was thinking to myself well I have not ask a stupid question on TractorByNet lately /forums/images/graemlins/grin.gif
I have a 60 MMM, how do you know if you have the blades upside down or not /forums/images/graemlins/confused.gif

 

[Dutch445]

I would say that the cutting edge of the blade should have a single bevel, or taper to the cutting edge. That bevel should be on the top of the blade, and the bottom of the blade should be flat across it's width right to the edge.. If you have an area that isn't cutting well,, it could be very possible it's upside down. A blade will still cut, although poorly without the sharp edge. maybe cut isnt' the right word,, shred, tear, stretch!
/forums/images/graemlins/cool.gif

 

[rwmeyer]

Another "quick & dirty " way of determining which way the blades are mounted is to look at the discharge chute on your deck. The cutting edge should face the opening of the chute. This helps throw the grass clippings out the chute. I can never remember which direction the blades rotate and its backwards anyhow 'cuz the deck is upside down. Facing the cutting edge towards the chute opening has never led me astray yet! Bob

 

[Lloyd_E]

Thanks for the replies. As Egon knows, we have had 7 days of rain, with serious damage to homes and bridges. I am glad I live on a hill. Egon, the carding mill in your town looked like it was going to float away today.

The grass in getting taller and I haven't had a chance to mow or work on ny fence project.
I starting to grow gills and look a little moldy. We are expected to get more rain over the next five days. This is causing serious problems for farmers trying to plant seed.

Normally we get around 124 millimetres of rain for this month. We have received so far 353+ and it is not over. There were times the rain has totalled 2.5 inches in 1 hour with flash floading.

My understanding for the mower blade is: flat part of blade is bottom with angle of blade facing deck - top.

This is a great little mower - 25 hp, 52" deck, high/low range, cruise control and parking brake. Oh, and a cup holder too! I mow just over 4-5 acres in 3-4 hours. I usually do the fields every two weeks and the home/acreage every week. Iwore out a 12 hp MTD over a ten year period trying to do the same thing. Fro what i can find this ubit is made by White with national branding stickers attached.

cheers,

lloyd

 

[Michigan_Mike]

I have a 60" mower with 3 blades.
The first time I took the blades off for sharpening, I didn't even think about alignment.
When I replaced them, and started the mower up, there was a terrible vibration. The vibration stopped before I could shut the mower down, but when I looked at the blades, they seemed to have realigned themselves. The next time, I paid more attention to the positioning, and the problem didn't recur.

 

[Snikpmot]

There is a alignment on the 52 inch deck I set it up last year,,,,,but alas the manual has done a disappearing act! I was sure hoping for a glaring answer. But,,,,

 

[Gary Fowler]

You can put the blade on in any position and they will not touch if you have the correct length of blade for the mower. As has been mentioned, the middle blade is set a bit forward from the two side blade and this allows for an overlap in cutting without the blades meeting. On a belt drive, there is no way to keep blades in sync since the belts always slip a bit especially of one hits a root, rock, tall grass etc therefore they have to be able to turn without hitting in any rotational pattern. The biggest problem occurs when one is placed upside down which is easy to do if you aren't careful. Bevel always faces up so it pulls up on the grass when cutting. Also the upturned wing at the end of the blade and opposite side from the cutting edge creates lift to raise the grass but if turned upside down, it will be whacking the grass down before it can be cut.


I don't think any size mower with belt drive has timed blades so blade placement is a non issue, just put them on with the correct side up and don't worry. Any vibration could be caused by an improperly sharpened blade where much more metal is removed from one side than the other. Another thing that may happen with some mowers is that the blade is not set properly on the shaft. Some shafts have a little protrusion that has to set inside the hole in the blade. Failure to properly set this into the blade so it sets flush will cause a lot of vibration. If it then settles into place as one poster said, then it will be loose on the shaft. This is very important to make sure you set the blade properly. My Craftsman 6000 has this protrusion, but my Ferris set flat on the shaft.

Another thing to watch is that most mowers have a cupped washer on the bottom which acts like a lock washer. The washer may look flat but if you set it on a very flat surface and look at it closely you will fine it cupped slightly. The cup faces upward so that when you tighten the bolt, it flattens the cup so there is tension on the bolt without overly tightening.