Ideas for rotary cutter build

[deanwerden]

Back to your no-gearbox belt drive mower idea, there used to be many more of these around. They seem to be out of style now



Bruce

I wonder if they advertised on here and immediately stopped production after everyone told them how STUPID of an idea it was

 

[deanwerden]

Sorry - I'm all for ingenuity, but throwing away 500 dollars on something that is 90% the same as a cheap-o rear finish mower is not a good plan. 500 bucks will get you a great 4' bush hog that will actually work. I like to DIY, but sometimes it just doesn't make sense. Farm implements and trailers are two of those cases.

You're right, I should load my homemade pallet forks, box blade and Iogsplitter onto my ****** homemade trailer and back it into the lake because it's all useless and have too much money invested in them

 

[Shaneard]

I wonder if they advertised on here and immediately stopped production after everyone told them how STUPID of an idea it was

You ask for answers you got answers. If you don't want answers don't ask questions. Nobody has said anything about it being a stupid idea.

 

[jenkinsph]

You're right, I should load my homemade pallet forks, box blade and Iogsplitter onto my ****** homemade trailer and back it into the lake because it's all useless and have too much money invested in them

There are lots of implements that you can build that are PRACTICAL as a diy project. Building a twin spindle 4' brush mower isn't. With folding blades these would only be about 6 inches long, not enough mass to do what you expect. Better to make a 6 hour drive and get a good used 4' brush cutter. Save your diy skills for more practical builds.

 

[hunterj]

When I had the 24hp tractor I ran a 42" bush hog I got used for $350, it would cut 1" saplings and grass with no problems. Cheaper than building one for sure.
A 2 blade setup increases blade tip speed which is better for grass, the single blade style blade tip speed and weight of the blade increases the inertia making it more suitable for brush and sapling. The finished look of the cut and cutting abilities are why we have multi blade and single blade systems. Designed for 2 separate uses. I'd say a 36 or 42 single blade would be best for what you want. Able to cut sapling and give a good finish.

 

[CDN Farm Boy]

Ok good info, The mass of the blades makes sense, I also like the tire driven set-up.

So can we at least agree that a 2 bladed bush hog style mower with heavy folding blades would at least be more successful in cutting tall grass than a mid mounted deck. The option of buying is well, not even an option. I can buy a 45hp gearbox for 120 bucks, might have 100 bucks in steel then misc bearings ect. I doubt I will have $500 into whatever I build. New is $1400 in Canada and I don't see any used ones within a 6 hour drive

Back to the drawing board I guess

I'm with the rest. Buy a proper rotary cutter. I'd thought about building something similar but 6' wide but decided it wasn't worth the work

Search Agdealer.com. There's lots of them available (both new and used) for under a grand and within 200 km of you.

 

[pmsmechanic]

Ok so lets go back to your original question and that was how to drive two 2' blades. I would build as per your drawings but I would not use idlers to tighten the belts. The reason being that V-belts don't last as long when you bend them "backwards" over a pulley. Two exceptions. Use a large enough idler pulley so the belt doesn't have to bend in such a short radius and you'll probably be ok. I can see your idea working really well with serpentine belts. They don't get the heat build up from flexing as they aren't as thick.

The other idea would be to make the gearbox sliding and don't use any idlers at all. You would then slide the gearbox to tighten the belts.

Mowers work on blade tip speed. Commercial mowers turn significantly faster than residential mowers do for the same blade length. So while 4,5 & 6' rough cut mowers work ok in direct drive ie 1to1 ratio on the gear box lawn mowers are sped up to keep the blade tip speed up. What I'm saying is that shorter mower blades turn faster to keep tip speeds up. Your drawing shows all the pulleys the same size. The driving pulley should be larger. That will get your tip speeds up the where they will cut grass etc.

Edited to add that if you look at belt tightening pulleys most are on the slack side of the belt. The side of the belt that has the most force on it ie the pulling side usually doesn't have the idler pulley on that side as that's the working side of the belt. The way your belts are running as per your drawing all the working tension of the belt goes over the idler. This will shorten belt life. Take a look at how the belts are on your mower deck. The "working" side of the belt is all without idlers and only the "return" side has idlers in it.

 

[TractorGuy]

I have been keeping my eye out for this mythical used 4 ft bush hog for 2 years and they are either 500 bucks and rotted to sh*t or new and $1400

Run a WTB ad in the Farm and Garden section of your local CL. That is how I got my brush cutter after tiring of waiting for one to pop up. Got my disc harrow the same way. Both are in better condition and were purchased at lower prices than any I saw advertised for sale. I paid $300 for my brush cutter and $270 for my 4' disc harrow. Someone has one laying around not being used and they are just too lazy to advertise but if they see a ready to buy customer they will come to you. My brush cutter is a 4' Howse and the disc harrow is a very heavy built unknown.

Any belt driven design is going to slip or break when you hit a tree with it. To shear trees you need the heavy flywheel action of a stump jumper and the rotating blade to handle the shock load when it makes contact.

 

[hunterj]

Price also depends on heavy, medium, or light duty.

 

[bspeedy]

You're right, I should load my homemade pallet forks, box blade and Iogsplitter onto my ****** homemade trailer and back it into the lake because it's all useless and have too much money invested in them

Ask a question and you'll get an answer. I build my own stuff all the time, but for the items I mentioned (and the items you've mentioned), most of us are better off buying than building.

Fact is, I just bought a 6x12 trailer. As the owner of plenty of metal working equipment, I priced out all the materials to build it myself and there is NO WAY I could do it for the price I bought it. Made absolutely no sense whatsoever. Used trailers are an even worse proposition. Funny coincidence is my trailers, log splitter and pallet forks are the ONLY implements I've bought new ever.

YMMV