how to get fly wheel off????
Any tricks to getting the fly wheel off of this thing?
I tried putting a strap arround it and tugging it with a come-along and giving the shaft a few slaps with a hammer.
Looked pretty funnny with chipper straped to the back of my Ford 8N
While i was standing there hitting it with the hammer.
I am planning on welding up some new arms for a 10 ton hydraulic gear puller I have and bolting it to the blower fan bolt holes.
Simmilar to a harmonic balancer pulley puller, but a lot larger.
This may be a decade late, but may be of use to someone. I recently bought a 1970's Woodchuck in running condition, but rough shape. It is a solid piece of industrial equipment and really eats through the brush, limbs, and logs. I was told it was a Asplundh Whisper Chipper. There were no plates, stamps, or other markings that were immediately obvious. After considerable investigation, I discovered it to be an old Woodchuck. After removing most accessories from the frame I found a plate on the frame lost under decades of grime and thick paint. I also found a manual on Ebay, which has helped out considerably, even though it is for a machine much newer than mine.
The machine had new blades, but I soon found out that the blades were not the right ones. They were smooth on the back and can easily vibrate loose and come flying out! They did not have the ridges that lock them to the drum. As I further investigated the machine, it became clear that it needed a complete overhaul - stripped down, rust removed, and new paint. Too many things had been patched together over the years. Little by little I got deeper and deeper into the project. With the belt and blades off, the play in the bearings was obvious. I decided to replace them too, so the machine would be in top shape for many years to come. Easier said than done!
After weeks of attempts and failures, I finally got the flywheel off last night. Here is what I did: The flywheel is attached to the shaft with a
TB Woods Type J J3 Sure-Grip Bushing, Cast Iron, Inch, 3" Bore, 5.1484" OD, 4.5" Length. This is a taper bushing. It tapers smaller out toward the end of the shaft. There are six holes in the flywheel, three that bolt the flywheel to the bushing, squeezing the taper in the flywheel bore onto the taper in the bushing which also squeezes the bushing onto the shaft. They are socket head bolts that recess into the flywheel and screw into the threaded holes in the taper bushing. The other three holes are to attach the fan to the flywheel. DON'T CONFUSE THESE HOLES like I did. I broke several puller set-ups, including one made with a 3/8" steel plate, before I realized I was pulling on the wrong holes. The holes that bolt the fan to the flywheel have threads in the flywheel itself. Those are the ones that grab the flywheel and pull it off. They look like they bottom out, but that is an illusion. The bottom you see is actually the face of the shoulder on the back of the taper bushing. If you look down the hole very carefully, you will see that there is a small space (1/8" or so) where the threads end before the bottom of the hole (the face of the taper bushing). That is the space that remains between the flywheel and the back of the taper bushing. Initially I was threading my puller into the other holes, with threads in the back of the taper bushing - the holes that attach the flywheel to the bushing. It had been apart for a while and I lost track of which were which. I studied it, and thought I had it right. Wrong! Make sure you get the holes correct and that you are pulling on the flywheel, not the bushing.
Once that light bulb went off, I expected it to be an easy task. After all, the other side with the drive pulley is set up the same way, and it came of relatively easily. Like many taper bushing and pulley or flywheel set-ups, the bolts that attach the pulley or flywheel to the bushing (or similar bolts) can be threaded into the other holes (the ones that thread into the flywheel or pulley itself, not the bushing), and when they bottom out, they push against the back flange of the taper bushing and force the bushing and flywheel to separate. Bingo, job done! Not so fast in my case. This machine is 40-45 years old and has been sitting out in the weather most of that time. The bushing was somewhat rusted to the flywheel. I had been soaking the joint with Blaster, and then in Kroil, for weeks. I bought some Grade 8 hardened bolts, applied liberal heat to the flywheel until it was nice and hot, then proceeded to tighten the bolts to separate the flywheel. With maximum torque on the bolts, something popped and one bolt got easier to turn, then another, and also the third. I thought I had it! But no, the 1" thick back shoulder of the taper bushing broke off! The bolts had literally shattered the taper bushing without separating the flywheel from it. The pieces jammed behind the flywheel preventing it from turning and making the chipper completely useless unless I got the flywheel off. It also made the rest of the job much harder without the ability to turn the shaft and flywheel.
My only option was to go back to the puller set-up I had been using. I had tried many configurations, but ended up using an old 12" section of railroad rail I had laying around. Nothing else I tried to pull (push) against was even close to strong enough, including large and heavy angle iron welded together. I drilled 5/8" holes in the 3/4" thick base of the railroad rail to receive the 5/8" bolts pulling on the flywheel, two on one side of the track and one on the other. I used 12" galvanized bolts from Lowe's to start, but then ended up using 5/8" all-thread with Grade 8 nuts. I would have used hardened all-thread if I had access to it, because I almost broke the 5/8" mild steel all-thread. The three pieces of all-thread screw into the correct holes in the flywheel. Then I ground the base of a 20-ton hydraulic bottle jack to fit between the all-thread and push against the shaft. Then the railroad rail bolted onto the all-thread to provide a base for the bottle jack to push against. No go! Even with liberal Kroil and lots of heat, the 20 ton jack with a cheater bar didn't even come close to freeing the flywheel. I beat on it with a block of oak and 12 pound sledge hammer, hammered directly outward on the railroad rail with the sledge, and tried everything else I could. It was not coming off. So I ordered a 50 ton hydraulic cylinder, thinking that would surely be enough. 100,000 pounds of force was about the tensile strength limit that the three pieces of all-thread could withstand before breaking.
Well, yesterday the 50 ton cylinder arrived. My 17 year-old son got home about the same time, so the two of us gave it our best. With liberal Kroil, a hot flywheel from sitting in the sun all afternoon, and over 50 tons of force, it was not budging. The 50 tons took the bolts to their limit. They started stretching with little pieces of metal jumping off the surface as they neared the breaking point. Again, beating on it with the sledge didn't break it free. The only thing left to try was additional heat. After about 15 minutes with a propane "Weed Dragon" flame thrower and a MAPP gas torch, the flywheel was more than smoking hot. I heard something, and then all of a sudden it popped off. The 300 pound flywheel literally flew off and landed on the ground several feet away. We were expecting it, so nobody got hurt.
Surprisingly, the rust between the flywheel and bushing was not very bad at all. But also, the Kroil had failed to penetrate very far into the joint. The name of the game is to apply enormous force between the flywheel and the bushing (or shaft) and get the flywheel very, very hot.
