replace 3/8" thick w/ 1/2" thick rotary blade?

[Ginormous]

I just bought a Woods M4-2 rotary mower, and the blades need to be replaced. I found a blade at Tractor Supply that is the same length w/ similar curves that I think will work. The big difference between the blades is that the new blade is 1/2" thick while the old blade is 3/8" thick. Since the blades counterbalance each other, my intuition is that it will work fine... and maybe better than the spec blades. Thoughts?

 

[Farmerford]

I have a 48" Bush Hog brand with 3/8" blades and a 60" Bush Hog brand with 1/2" blades. When cutting side by side in heavy grass/weeds the thicker blades seem to require greater power than the thinner blades, after taking into account the diffence in mower sizes. I don't think I am imagining it; but I do not know if it is a result of sharper blades (I don't think so), more air resistance (seems unlikely) or just the reduced force needed to push the thinner blade through heavy grass. If you select the thicker blades, I would be interested in your experience.

PS: You will need new blade bolts since the shoulder part of the old blade bolts will not be long enough even though the diameter may be the same.

 

[Ginormous]

I have a 48" Bush Hog brand with 3/8" blades and a 60" Bush Hog brand with 1/2" blades. When cutting side by side in heavy grass/weeds the thicker blades seem to require greater power than the thinner blades, after taking into account the diffence in mower sizes. I don't think I am imagining it; but I do not know if it is a result of sharper blades (I don't think so), more air resistance (seems unlikely) or just the reduced force needed to push the thinner blade through heavy grass. If you select the thicker blades, I would be interested in your experience.

PS: You will need new blade bolts since the shoulder part of the old blade bolts will not be long enough even though the diameter may be the same.

I bought this 48" bush hog because people told me that a 60" requires a lot more HP and that it would likely be too much for my 20 HP Yanmar. That may be what you are noticing between your 2 sizes, not sure. I just bought the mower, so unfortunately I won't be able to compare how it ran with the thinner blades to these thicker ones.

The 1.5" bolts that hold the blades on on this Woods mower, there are spacer plates. I am counting on being able to leave out one of those spacers to accomodate the thicker blade. If that doesn't work out, I'll be taking them back. BTW, one reason I went with these thicker blades is that they were $60/pair vs. $120/pair for the Woods blades it is supposed to use. I also like the idea of the thicker blade, seems like it will be more rugged.

 

[clemsonfor]

Go to Agrisupply.com. they have far more than TSC and often will ship to your house for less than TSC. If you live near one you can really get a deal.

Just looked.

Not sure if this is the blade size you need but here is a 3/8 Woods blade.

http://www.agrisupply.com/product.asp?pn=10511&sid=&eid=

I Put them in the cart and there was $16 shipping to my house. For a little under $52 i can have them brought to my house. Assuming these are the correct blades TSC can keep there high priced stuf and i will let ASC deliver to my door and save my $4/gal fuel for my tractor and boat! The company is great, they will take anything back as well even if your not satisfied with it. Also there discriptions can often be very generic or similar to another item. Call them and talk to a rep they have more detailed notes and often times talk to a "tec " who can most of the times answer your question as to specifics.

 

[Ginormous]

Clemsonfor -- thanks for the tip on Agrisupply. No stores near me, but I saved their link. Unfortunately, it doesn't look like they have the right Woods blade either. The one I'm replacing is 4"x20"x3/8". One nice thing about going to the local Tractor Supply store is that I was able to set the blades they had on top of and next to the one I'm replacing. The one I picked out is the same height and width, but 1/2" vs 3/8" thick. Again, hopefully it works...

 

[bjr]

I've 5' Bush Hog Brand that uses the 3/8" thick blade as well, and the bolt hole is smaller (1-1/4") most blade are 1-1/2" hole. Just keep that in mind as well. Don't seem to be able to find a less expensive aftermarket blade and always have to go with OEM blades. bjr

 

[bcp]

Drill holes in the heavier blade to lighten it. With the right size and arrangement of holes it will sound like you have a turbine powered tractor.

Bruce

 

[Ginormous]

bcp -- good thought on lightening the blade... especially the part about it sounding like a turbine engine. If my tractor sounded like the old Batmobile when Batman hit the turbo button, well, that would be priceless... Holy tractors, Batman, is that a bush hog firing up???

 

[Ginormous]

I got the mower reassembled last night and took it out for a spin. I only ran it a short distance over some tall grass -- it was already dark out -- and it seemed to cut great. It sounded just like a big fan whirring away and it left a nicely cut path. :thumbsup: