Mowing Anti can opener treatment for rotary mower

[TractorGuy]

Just chalk it up to good luck on your part. Got mine 1st or second use, nothing worn, nothing loose.

I'll chalk it up to you guys bought some very poorly designed mowers.

If I had that happen to a new mower it would go back for a full refund and I would be shopping for a different brand.

 

[Beaver Cove Deere]

Never had any blades make contact with any of my mower decks. Something is worn or loose to make that happen.

I can assure you that nothing is loose or worn.

 

[crazyal]

In the land of sand this never happens. But up in the rocky lands metal blades will flex when they hit rocks or ledge. If they flex far enough the deck gets hit. I had an old Craftsman that would break the aluminum part that holds the bearings for the blade. It was so common that there were hundreds selling replacements on ebay. I had a Troy Built that the blade bent down when a rock got lodged between it and the deck. For a few seconds it was cutting nice round circles in the grass. It stuck down so far I couldn't even drive back to the garage with the deck on. But that's life in the land of rocks where the winter frosts push new ones to the surface. I've finally got to a point where they are minimal.

 

[John_Mc]

In the land of sand this never happens. But up in the rocky lands metal blades will flex when they hit rocks or ledge. If they flex far enough the deck gets hit. I had an old Craftsman that would break the aluminum part that holds the bearings for the blade. It was so common that there were hundreds selling replacements on ebay. I had a Troy Built that the blade bent down when a rock got lodged between it and the deck. For a few seconds it was cutting nice round circles in the grass. It stuck down so far I couldn't even drive back to the garage with the deck on. But that's life in the land of rocks where the winter frosts push new ones to the surface. I've finally got to a point where they are minimal.

Exactly. If all you are doing is using it a a glorified lawn mower, and the worst it ever sees is a few saplings, you will likely never have a problem. However, even the hardened rotary cutter blades will bend if they are hit hard and often enough. With a lighter hit, they will (mostly) spring back, but with a hard hit on a good rock or stump, they'll take a little bend. Do that enough, and they slowly move closer to the deck. Before too long, they are within flexing distance of the deck. If you harden the blade enough to prevent it from bending, it will shatter, rather than bend. I've never "can-openered" my deck, but I do have some bulges, and I managed to beat a hole in the bottom of one of th ebox channels on the underside of the deck. (Since welded back up.) The are only two ways I know of to avoid this:

1. Don't hit anything that solid (not happening in my area. We've got a lot of rocky, rough terrain, and I bought this in large part for trail work. That nice flat meadow I mow occasionally probably counts for only 5% of its use.)
2. Replace the blades before they get bent far enough to be within flexing distance of the deck. (I've never had any luck straightening them back out.)

I'll chalk it up to you guys bought some very poorly designed mowers.

If I had that happen to a new mower it would go back for a full refund and I would be shopping for a different brand.

If I hit something hard enough to bend a blade that badly on first use, I'd be bummed, but unless I had bought some cheap no-name junk, I would be more inclined to blame myself than the manufacturer. I've owned my Woods BB60 for 19 years, and it has had a rough life. Yes, it's a bit worse for the wear, and you can see a bit of an outline of the ends of the blades along part of the deck, but I'm happy with it. It has held up well to the rough service it has seen.

 

[Zebrafive]

"never any luck trying to straighten blades"

How did you try? Hydraulic press?

 

[Zebrafive]

"never any luck trying to straighten blades"

How did you try? Hydraulic press?

 

[skipmarcy]

Get a mower with some decent blades on it. I've had my very OLD, used Howse 6' for over 20 years and the only time the blade(s) hit the deck was when a weld broke on the bar that the stump jumper bolts to. I have hit so many rocks and stumps and just plain earth with that mower over the years it's amazing that old, "cheap" brand mower is still going strong. It uses 7/16" shear bolts and I have broken dozens over the years. The blades are 1/2" thick and do not bend. Originally the blades were flat when I bought the used mower and I used my torch to heat the backside of the tip to bend it up for a little lift to help cut plain grass a little nicer. The one time I bought new blades and bolts they came with a very slight bend for lift and I added a little more to it in the same fashion. I don't use the cutter but about once a year now and will be here very soon. I replaced seals in the gearbox back when I bought it and haven't lost a drop of lube in all these years - I swear I think that gearbox must be rated for 100 hp on that 6' cutter !!

 

[TractorGuy]

My old Howse mower was an antique when I bought it. It's been backed over stumps that killed the tractor engine and no telling how rough it was treated before I got it. No sign a blade has EVER touched the deck.

 

[John_Mc]

Get a mower with some decent blades on it. I've had my very OLD, used Howse 6' for over 20 years and the only time the blade(s) hit the deck was when a weld broke on the bar that the stump jumper bolts to. I have hit so many rocks and stumps and just plain earth with that mower over the years it's amazing that old, "cheap" brand mower is still going strong. It uses 7/16" shear bolts and I have broken dozens over the years. The blades are 1/2" thick and do not bend. Originally the blades were flat when I bought the used mower and I used my torch to heat the backside of the tip to bend it up for a little lift to help cut plain grass a little nicer. The one time I bought new blades and bolts they came with a very slight bend for lift and I added a little more to it in the same fashion. I don't use the cutter but about once a year now and will be here very soon. I replaced seals in the gearbox back when I bought it and haven't lost a drop of lube in all these years - I swear I think that gearbox must be rated for 100 hp on that 6' cutter !!

Back when I was in the market for a 5' rotary cutter, Woods was selling the BB60 and the BB600. I bought the BB60 for weight and price. It came with 3/8" x 4" blades. The BB600 came with 1/2" by 4" blades. I just checked their site. The model numbers have changed: The options are now the BB60.30, BB60.50, and BB60.60. All of these come with 1/2" x 4" blades. I'd love to be able to swap to these, but the attachment system is different. My dealer has never done a swap but said it would involve more than just replacing the blades and bolts, and might not even be possible without replacing the whole stump jumper/crossbar assembly It's just not worth it, unless something breaks, requiring replacement anyway.

BTW, hitting a stump solidly enough to stall the tractor (or break the shear pin or slip the clutch, depending on what you have) is not what bends a blade, it's the repeated glancing blows on a rock. I've checked before and after when chewing up stumps and not seen a noticeable difference. I suspect the blade is more likely to dig in to the stump and then swing back out of the way (as brush mowers are designed to do). I have a few very rocky recreational trails that I mow only occasionally. It would be better if I mowed them regularly, since I would remember or could see where the worst rocks are. If I start with straight blades, I can see the start of the bending after a few passes, but it takes a LOT of passes for it to get easily noticeable. I'm just about to replace the blades now, after about 6 years of use/abuse. I have no indication that these are close to hitting the deck, but I can see a noticeable difference in shape between the new and the old.

 

[John_Mc]

"never any luck trying to straighten blades"

How did you try? Hydraulic press?

I've tried beating on them with a sledge hammer (can't even tell I've done anything). I don't own a press, but tried jury rigging one using my hydraulic splitter. THat did not work, but I also did not have the guts to push it as hard as I could have.

When the ones I'm taking off now come off, I'm going to bring them to a friend who runs a fab shop and see if he can do anything with his press. I do not want to heat them, since that will destroy the temper if they are heated too far.