jb1390
Gold Member
I bought a 6' bushhog off of craigslist a couple months ago. It is a small-name brand manufactured in pennsylvania. In general it seems to be pretty well built, with channel steel for side structure, and 2.5" box tubing for frame rails above the deck. I've run a few styles of blades with it - the original blades had a slight bend in the corner, which provided a slight updraft. I used these blades for some heavy brush cutting the first day I had it, and I noticed a ring of dents starting to appear around the deck - which I figured was due to the blades throwing debris upward into the sheet metal. I changed the blades shortly afterward to a flat style, that I use for heavy brush cutting. The ridge did not seem to get worse, I probably put about 20-30 hours on it through briar patches and other brush with the flat blades.
I recently mowed 13 acres of pasture - which is 99% grass, with the remaining 1% being weeds and rocks. I installed a set of high lift blades, which worked very nicely for lifting the grass up where weather/tire tracks had laid it over. The cut was great - but I noticed the ridge getting worse- to the point that there are a few small holes all the way through the deck. I did hit a fair number of rocks while mowing. I was also running at pto speed or slightly higher - which would make the blades less prone to swing when hitting an obstacle due to high centripetal force.
From what I've read, the blades should never hit the deck, unless something is wrong - but I can't find anything obviously wrong. There is probably 3" or so of clearance between the high lift blade and the deck, and very little slop <.010" in the spindle pin. The blades are not bent, and the stump jumper is in great shape - verified to be good using a dial indicator. The blade bolts are also in good shape - pretty tight, with just enough clearance to allow the blades to turn. When I push hard on the blade, I can make it bend - everything else (including gear box mount) is tight.
My only theory is that when I hit low, angled rocks, it deflects the blades enough to push them up into the deck. Close examination indicates that the blades are actually touching, and it's not just debris being thrown into the deck. This particular mower has lower sides than some (like a woods) - which would likely make it more susceptible to the blades hitting due to lower clearance. The high lift blades also sit closer to the deck than flat ones. It seems like the easiest fix is to add some thicker material to the bottom of the deck - so that when the blade hits it doesn't matter. Also, pull the rocks out where possible - though hitting rocks is par for the course with a bush hog. I could also move the gearbox and extend the sides - though that seems like significantly more effort than adding some wear plate to the underside.
Anybody else run into this kind of issue?
I recently mowed 13 acres of pasture - which is 99% grass, with the remaining 1% being weeds and rocks. I installed a set of high lift blades, which worked very nicely for lifting the grass up where weather/tire tracks had laid it over. The cut was great - but I noticed the ridge getting worse- to the point that there are a few small holes all the way through the deck. I did hit a fair number of rocks while mowing. I was also running at pto speed or slightly higher - which would make the blades less prone to swing when hitting an obstacle due to high centripetal force.
From what I've read, the blades should never hit the deck, unless something is wrong - but I can't find anything obviously wrong. There is probably 3" or so of clearance between the high lift blade and the deck, and very little slop <.010" in the spindle pin. The blades are not bent, and the stump jumper is in great shape - verified to be good using a dial indicator. The blade bolts are also in good shape - pretty tight, with just enough clearance to allow the blades to turn. When I push hard on the blade, I can make it bend - everything else (including gear box mount) is tight.
My only theory is that when I hit low, angled rocks, it deflects the blades enough to push them up into the deck. Close examination indicates that the blades are actually touching, and it's not just debris being thrown into the deck. This particular mower has lower sides than some (like a woods) - which would likely make it more susceptible to the blades hitting due to lower clearance. The high lift blades also sit closer to the deck than flat ones. It seems like the easiest fix is to add some thicker material to the bottom of the deck - so that when the blade hits it doesn't matter. Also, pull the rocks out where possible - though hitting rocks is par for the course with a bush hog. I could also move the gearbox and extend the sides - though that seems like significantly more effort than adding some wear plate to the underside.
Anybody else run into this kind of issue?
