I posted this a while ago, here it is again.
I finished making a 3 pt leaf blower for my B2400 a couple of weeks ago. It is impressive how much air it will put out! I made a variable size nozzle for the discharge. With the nozzle full open it takes most of the 18 PTO HP to drive it.
A friend gave me a basket-case industrial blower. I had to weld new metal to replace what was rusted through on the entire outer diameter of the blower housing. I also had to replace half the metal on the sides (cheeks). The rotor was in good condition. After all the new metal, two primer and two finish coats of paint it looks like new.
The blower needs to turn at 2500 to 3000 RPM for the best output. To gear up from 540 RPM, I used two jack shafts. The first one is 1/38" dia. The PTO attaches to this. There is a 12" dia pulley that drives a 4" dia pulley on the 2nd shaft which is 1 1/8". Also on the 2nd shaft is a 6" dia pulley that drives a 3 1/4" pulley on the blower shaft (diameters are approximate). All these are two V-belt type pulleys. This results in a blower speed of 3100 RPM at a PTO speed of 540. The blower actually works well at a slower engine speed of 2000 RPM which is only 2400 RPM at the blower.
I made the frame from c-channel and angle iron to connect the blower, jack shafts and 3 point hitch mounts.
What used to take 2 to 3 hours with my 5 HP push blower takes about 15 min. with the PTO blower. It is also a lot more fun. I have to be carefull, since two times now, I have blown my wife's flowers near the mailbox right out of the ground, root ball and all. The blower puts out so much air that I typically have the adjustable discharge nozzle I made for it half closed. I also usually run it at only 2000 tractor RPM (PTO speed is at 2600 tractor RPM).
Andy