Rotary Cutter New to rotary cutters, have questions, help please

[StrangeRanger]

Now that I think about it... any reason appropriately sized grade 8 bolts can't be used on the blades? With maybe some of them thar "oblong" shaped locking nuts or ???
j

 

[B8FISH]

Hmm--wouldn't a side chute be more indicative of a finish mower than a "bush hog". Would also seem to be a good reason for the pulley set-up to get over 2,000RPM out of a 540 RPM rear PTO.

 

[N80]

Hmm--wouldn't a side chute be more indicative of a finish mower than a "bush hog". Would also seem to be a good reason for the pulley set-up to get over 2,000RPM out of a 540 RPM rear PTO.

I think this thing defies definition. But, the two blades on a single spindle probably makes it closer to a rotary cutter than a finish mower. I doubt it ever provided a 'finish' quality cut, even in its better days.

As far as new bolts for the blades, yes, I think grade 8 bolts, lock washer and red loctite would be fine.......probably the most reliable part on the whole machine. I hope our kidding isn't bothering you, but that machine is so interesting and unique that its bound to draw a few zingrs here and there. And I think it is safe to say that if you can get it running with a bungee cord, a few dollars worth of bolts, etc etc and get the job done without killing somone or causing any major equipment damage....you might be a legend around here.

We will be expecting a video!

 

[StrangeRanger]

Hmm--wouldn't a side chute be more indicative of a finish mower than a "bush hog". Would also seem to be a good reason for the pulley set-up to get over 2,000RPM out of a 540 RPM rear PTO.

Heh... this thing was never anything close to a finish mower. The round blades are proof of that
j

 

[studor]

I would give it a shot
I think Pycoed was saying if you move the tensioning pulley closer to the center you will get more belt on the bottom pulley creating a better "pull" with less belt slippage ( more belt surface on the bottom pulley).Of course you will need a smaller belt.
Did you sort out the driveline? Maybe your welder buddy can create a sleeve?
You could use grade 8 bolts but you can probably find a set of rotary mower bolts to use based on the blades you find.

 

[Soundguy]

Actually the only opening is the side discharge chute. The front and back are closed. And the side opening is about maybe a foot wide, so I'm not even sure a blade would fit through it But adding some chain or thick rubber mat is probably a better safe than sorry idea I should do. Plus if it works, I will probably plug the side chute and open the back. I'd think that would help w/ clogging issues.
The blades are totally shot. They have to be replaced. Hmm... think I'll see what happens.
j

Remember.. it only has to be big enough for a piece of blade to get thru.. rubber flaps can bleed alot of energy off.

soundguy

 

[Soundguy]

You can get gr10 at some places even.

soundguy

 

[StrangeRanger]

Ahhh... more belt on pulley ~ angle stuff.. that makes sense. But I actually like the idea of less power for now. That whole set up is my safety system for now and I'd prefer lots of slippage until I see how it really goes.

Good point about the whole only needing to be big enough for a piece of blade to fit through. All the more reason to block up that side hole and go out the back.

Welding bud did offer to help w/ drive line issue, but I think I will try the $19 PTO extender idea first.

Now if I can get the wife to give some time to play I might actually be able to get started on this nonsense
j

 

[pycoed]

I would give it a shot
I think Pycoed was saying if you move the tensioning pulley closer to the center you will get more belt on the bottom pulley creating a better "pull" with less belt slippage ( more belt surface on the bottom pulley).Of course you will need a smaller belt.
Did you sort out the driveline? Maybe your welder buddy can create a sleeve?
You could use grade 8 bolts but you can probably find a set of rotary mower bolts to use based on the blades you find.

Correct - try to get a look at the belt layout on the deck of a rideon mower. The makers go to great lengths to get as much angular contact as possible beween belt & pulley. On the triangular belt set up on yours there's only a max of 120 deg of contact i.e. the belt only touches 1/3 of each pulley circumference.
Put a belt over the PTO & gearbox pullies only, & you get 180 deg contact, then tension it by pushing the belt together between the two & you might get up to 200 deg. . At that it might just handle cutting, but don't waste your time with your current set up - you won't cut 50 yards in any length of grass before the belt will burn off.
Keep the tensioner as near as possible to the small gearbox pulley to maximise the wrap around on that.

 

[Glowplug]

Remember "Bush Hog" rotary cutters don't have any "openings" in the front or rear and they have either chains or rubber deflectors in those locations. The only way you're not going to have any kind of open space is if you drag it along on the ground. Then it would be some sort of strange PTO powered box scraper!!

I'm getting more intrigued by this thing! Keep the progress posts coming! I just hope we don't find out the results of your starting it in the newspaper! . . . . . . ..