Flail Mower Chicomm Flail mower vibration cured

[def38]

My flail mower (made in China) recently developed a severe vibration. I crawled around under it while running at idle to determine the source of the vibration. Nothing in the rotating system was amiss, no missing hammers, nothing seemed out of the ordinary. I did observe what I thought was a bit of runout in the top pulley bearing so, I ordered a FAG bearing and new oil seal, about $20.00, free shipping.

So, I went out to the shop to tear into the mower and replace what I thought was a bad bearing. I removed the belts, checking all the bearing clearances and the gearbox for abnormal wear and runout. I found none. Even the suspect top pulley bearing showed no abnormal wear.

However, I noticed the U-joint at the gearbox end was at a different angle that the U-joint at the tractor end. This condition usually promotes stress on the joints due to the different joint speeds operating through different angles. So, I loosened the mounting bolts on the gearcase and made the angles equal at both ends of the PTO shaft when the mower was in the operating position. I spun up the mower and the vibration is gone. If you have vibrations, check the angles through which your PTO U-joints are operating when the mower is lowered in the cutting position.

BTW, do any of you folks with hammer flails sharpen them at home? Mine are a bit dinged up from rocks and Buick hubcaps. Let me know please.

 

[TerryR]

BTW, do any of you folks with hammer flails sharpen them at home? Mine are a bit dinged up from rocks and Buick hubcaps. Let me know please.

I'd done it with an angle grinder. Works pretty well with my ditch and bank flail because I can set it up on end. Do be careful not to get them too hot. You need to fix them from swinging. I find a couple of 1x2's running across a bunch of them, and a couple of bar clamps, do that pretty well..