Alamo SHD74 flail mower repair

[Smokeydog]

Winter project. Bought mower used and knew rear roller had some bad rust issues from sitting. Mower has the large rear wheels option so rear roller only touches ground on high points. Rust and perforation weakening the roller. Repair before totally ruined.

New roller $2,000 so no go.

Took a while to find a drop at scrap yard of 6” pipe. 0.188 wall, 8.5’ long , $33.

Removed the roller from mower. Still straight and bearings good beside not able to grease. One fitting was broke off and other worn or rusted unable to lock coupler on. Needed to remove to repair anyways.

Grass and debris had packed inside the roller. Cut a 5x3” hole around the biggest perforation. Used hand, air and finally water hose to clean debris from inside of the roller. May weld in a patch.

Cut the repair pipe 68.75” long. Be welded to the roller bearing hubs. Roller 6” OD tube steel. Pipe 6”, about 6.125”ID, 6.5”OD. Also cut off a small ring for fitting test. Plan welding pipe over original tube. Slit the pipe longways. Cut a small strip so the new pipe can be tightly clamped around the old tube and seam welded. Gap for a good weld bead to fuse together. Going to cut out the pipe welded seam for tight fit. Also weld around ends. Add seven plug welds to tie the two together. Thinking about once welded, drilling a hole thru and adding a pint of oil, then weld closed. Oil to help stop further corrosion inside.

Test ring to determine how much to slit the pipe. Work in progress.

 

[nyone]

I use to repair these mowers for a major municipality. Very rarly did we change rollers and these things would drag on the road for miles and miles every year. On occasion I would have to weld the end cap a bit better on the roller.

I would just cut the end cap off and weld the new tube on the end cap. Fill in where needed. Tack weld in the beginning, put it on the mower and check for straightness.

 

[Smokeydog]

I use to repair these mowers for a major municipality. Very rarly did we change rollers and these things would drag on the road for miles and miles every year. On occasion I would have to weld the end cap a bit better on the roller.

I would just cut the end cap off and weld the new tube on the end cap. Fill in where needed. Tack weld in the beginning, put it on the mower and check for straightness.

Options and experience feedback is exactly why I posted. Thank you.

Hoping the roller tube holds the bearings in alignment and welding the outer pipe on doesn’t mess that up. There is size difference between the pipe and end caps that would need to be considered…challenging my skill set. Not worried about adding 80# of weight to the roller.

Pipe has no where near the tolerance spec as tubing.

Bought the mower from a dam engineer. TVA hydroelectric dam. Suspect he got it from surplus auction. Sitting prolonged time outside, salt or fertilizer could have caused the significant corrosion? Other parts not damaged or worn. He had replaced all the blades and hangers with HD cutters from Failmasters. He replaced the bearings in rear caster wheels. After a year of cutting the blades still look new. Didn’t have rear wheels adjusted best, dam engineer. Just like saying that.

Bought this one because of the rear caster wheel option. Hillside farm with many small, tree lined patches requiring lots of turning and backing. Not having to slide the roller while maneuvering a significant difference. Smooth moves.

 

[John0829]

For what it worth I had to have one repaired a couple of years ago and I took it to a local machine shop that does drive lines. Cost me $400 to have them do it. I told them to reuse the end caps but they instead made it all new, end caps and roller.

 

[dieselscout80]

For what it worth I had to have one repaired a couple of years ago and I took it to a local machine shop that does drive lines. Cost me $400 to have them do it. I told them to reuse the end caps but they instead made it all new, end caps and roller.

The Alamo end caps have a hexagon shaft that goes into the bearings on each end/side.

 

[Smokeydog]

For what it worth I had to have one repaired a couple of years ago and I took it to a local machine shop that does drive lines. Cost me $400 to have them do it. I told them to reuse the end caps but they instead made it all new, end caps and roller.

Think that’s the proper way to repair. Have had driveshafts made before so you got a good deal. They have the right tooling to make an expert repair. If I really mess up might be my next stop.

 

[Smokeydog]

Few hours between rain showers. Repair design change. Test ring was tight with one 1/4” spacer. Less than 1/8” around the circumference. Shaped 2”, 12ga, 0.106” strip ring to center the pipe to the hubs at both ends. Not going to cut the pipe long ways and reweld. Going to rely on the ends, +40” of weld and 12, 1/2” plug welds. Like 12, 1/2” bolts to tie the two tubes together.

New grease zerks for bearings. Preparing metal for welding. Dirty and tedious work. Will weld clean out patch back in.

 

[nyone]

It's really low speed so no need to get it balanced. Just eyeball it.

 

[Smokeydog]

It's really low speed so no need to get it balanced. Just eyeball it.

Not worried about balance. Do want the hub stubs to run true. The bearings appear to be pillow block or flange type that align to a straight shaft. Not having to remove bearings to repair with the larger diameter pipe.

Waiting for a morning’s rain to clear and get my old bones in gear.

 

[Smokeydog]

Gap in spacer strip is for the weld bead inside the pipe. Welded up fine. A good welder could have welded without the need to grind. I’m not that welder. Have a good rounded shoulder.

Heavy duty and heavy. Collapsed my woodworking roller stand while installed pipe. Had to use tractor to pick it back up. Ordered a second pipe stand.

Thinking now 4 plug welds around the middle to tie the two tubes together will be plenty if even needed.