Finish Mower Cut Quality

[podzie]

Last month I changed the blades on my Bush Hog FTH-480 finish mower. I had two choices of blades..regular or uplift.

I didn't know the difference so I just bought the regular. I changed the belt as well while I was there, using the same Napa 73 I always have used on it.

Now, when I mow, the left side seems to leave a lot of uncut grass. I literally have to make my runs such that I re-mow that part with the right side on the new pass.

I tried tightening the belt, and also running full throttle in case it was a blade tip speed problem....still does it.

Heck, I even took the blades back off, to make sure I put them on the right way, gave them a quick pass with an angle grinder to be sure of the edge, and it still cuts poorly.

Anyone know what this old boy did wrong? Should I have bought the uplift blades? Does anyone else use a different belt on the FTH-480? I'm pulling this behind a Kubota B7100 if that matters.

Thanks, guys!

 

[have_blue]

How high are you cutting?

I've noticed my RFM cuts much better when I cut low, say 2-3" than when I cut 4-5". I don't like to cut that low, but it cuts ragged otherwise.

 

[podzie]

Cutting at 4", so maybe that's it.

Also, the yard is largely bahiagrass and it's pretty dry here. Maybe that has something to do with it?

 

[dodge man]

Are you absouletly sure the blade is tight? I had a blade come loose on my MMM and I'm pretty sure it put it on tight. I ended up using an impact to get it good and tight. Sometimes there are some special washers and such to keep the blade from slipping on the spindle. Are they all in place and in good shape? Just throwing out ideas.

 

[ttstraw]

I just got me a Woods 60" RFM with rear discharge and what I have noticed is the quality of cut really depends on the blade speed. The 2920 I use is heavy and it mashes the grass under the tires, the combination of a high lift blade and the speed at which it is spinning determines if that smashed grass gets sucked up so it can be clipped off. Mine will cut at 2K RPMs and not bog at all but the cut is not as nice as if I really spin the RPMs up. I have no idea if my mower has high lift blades or not, something I will have to check out. But for your one side not cutting as well, dont take this the wrong way, but I would make sure that blade is not on upside down and then make sure you didnt mis-route the new belt which could cause that blade to spin backwards. The only reason I say this is a saw a pretty mechanically savvy guy put all 3 of his new blades on upside down once....so it happens to the best of us.

 

[NewToy]

I have a Landpride mower and they offer three different blade options; lo, med and hi lift. The high lift gives the best cut by far but creates a dust storm if you hit a bald spot. The lo lift does ok and is my preference in the real dry weather. It also takes me more fuel to cut with the high lift as they really churn up the air, you can hear the difference easily between the two sets of blades. I haven't tried the med lift yet, that's my next set.
John

 

[podzie]

Thanks guys. I'll go back and check the blades and belt and run an impact on the bolts to make sure all is tight.

 

[EddieWalker]

Another thing to check is the spindle. Is it tight and true? While under there, see if there is any slop or movement by tugging and twisting on the tip of the blade. Do you grease your spindles on a regular basis? Could a previous owner have neglected greasing the spindles?

Is the blade flat and true? Even brand new, it might have been damaged in shipping. With one side doing this and not the other side, I'd also consider trading blades and seeing if anything changes. Since you double checked to make sure you have the blades on the right way, it's got to be in the spindle or the blade itself.

Good luck,
Eddie

 

[podzie]

Well, today I tried everything. Swapped blades, put extra tension on belt, impacted blade bolts. Nothing worked. I still have this "not very well" cut path on the left side.

One thing that I did notice with all of the blade swapping is that the blade washer (the large one that is grooved on one side to fit the spindle) kept falling off after I would unbutton the blade. The right side stays up there on its own. Is there supposed to be a bearing or race on the other side of this that maybe I threw?

There is zero play or flop in the spindle itself. It spins very tightly and true.

 

[have_blue]

Cutting at 4", so maybe that's it.

Also, the yard is largely bahiagrass and it's pretty dry here. Maybe that has something to do with it?

There's your problem. Bahiagrass, especially when it's dry, is the toughest grass I can think of. You need very sharp blades and dangerous blade tip speeds to cut the tough wispy grass cleanly. Cutting shorter will also help a little, but you don't want to do that in dry weather. Bahia cuts cleaner when it's fresh and green, but is always a tough grass to cut.