Alamo SHD74 roller repair

[Smokeydog]

Rust had perforated and heavily pitted the rear roller of a used flail mower I bought early this year. OEM replacement $2,000, driveline shop retube $4-600. Scrapyard 6” pipe $33. 0.188” wall.

Roller was full of debris. Cut slot to remove and wash out.

Used a test ring cut from pipe to confirm fit over tube. Made two spacer strip rings from 12ga to tightly fit pipe to tube, fill gap and center pipe on tube hubs before welding.

Thinking of adding four 1/2” plug welds to the center to tie the two tube together for added strength? Also thinking about adding a quart of oil before sealing the last plug weld to prevent more rust from nearly 30sqft of internal surface area? Got a rain day to think about that.

Roller now 6.625” diameter and 80# heavier.

 

[Yooper]

That’s the way to do it! Nice job. No need to plug weld for strength. Plenty strong as it is. Adding oil is not necessary. That wall thickness will outlast the machine.

 

[GreensvilleJay]

I'd drill a hole for 1/4" pipe plug and pour some thick oil in, say 1/4 cup ? Over time, heat and spinning will coat the inside.
Curious as to why the rot in the first place ? Seems 'odd' location.

Have a section of 1/2" wall 6" here. Standing in corner cause I need forklift to move it ! Too good to toss back into the bin but after 14 years STILL haven't found the 'perfect' use for it.

 

[Smokeydog]

I'd drill a hole for 1/4" pipe plug and pour some thick oil in, say 1/4 cup ? Over time, heat and spinning will coat the inside.
Curious as to why the rot in the first place ? Seems 'odd' location.

Have a section of 1/2" wall 6" here. Standing in corner cause I need forklift to move it ! Too good to toss back into the bin but after 14 years STILL haven't found the 'perfect' use for it.

Took awhile to find 0.188” wall, 6” pipe drop.

Guess been sitting outside for sometime before being surplussed. Fertilizer? Bacteria forms blisters to convert (eat) steel into rust and release energy. That’s pitting can be so damaging. High carbon steel has more potential energy and even easier to pit without protection.

Great cutter and hope last long time.

 

[GreensvilleJay]

hmm, 'well pipe' could have worked for you.
I KNOW it made a GREAT muffler one year, though did need a couple extra support brackets.
sadly most everything I now own will outlast me.....

 

[Lil Foot]

I have a feeling I may have to do something similar one of these days to my roller.
P.O. said his grandfather built it in the '40s, and it has always been stored outside, parked in the dirt.
(note the pitting)
I have it sitting on plastic deck boards, and it is pretty dry out here, but someday.....
Maybe it will outlast me.

 

[Smokeydog]

Decided to add four, 1/2” plug welds around the center to further tie the two tubes together for strength. Super Heavy Duty. Also injected about a quart of Rotella engine oil before sealing the last weld. Corrosion and about 30sqft of internal surface area. Good use for an old turkey injector syringe. Ready to reinstall.

 

[Runs With Scissors]

Nice idea to sleeve that thing!

The only change I may have made would to have used "used oil" for the oil injection part.

But thats mostly because I collect my used oil for the future "waste oil furnace" project.

 

[mcmxi]

Took awhile to find 0.188” wall, 6” pipe drop.

Guess been sitting outside for sometime before being surplussed. Fertilizer? Bacteria forms blisters to convert (eat) steel into rust and release energy. That’s pitting can be so damaging. High carbon steel has more potential energy and even easier to pit without protection.

Great cutter and hope last long time.

Well done on the repair!

For the record though, high carbon steel is more corrosion resistant than mild steel. A coat of paint combined with keeping the drum free of an electrolyte will go a long way to increasing the longevity of the drum. I keep my flail on a pallet over the winter and it's covered with a tarp. Corrosion isn't a big problem up here due to the lack of chlorides and relatively low humidity and rainfall totals.

 

[Smokeydog]

Seems like the higher end flail mowers have larger cutting diameters and larger rollers. With so many variables of types and numbers of cutters it’s hard to compare. Several of my friends that have Asian imports don’t get the cut quality with one pass as these Alamo cutters.

Used oil might have had significant loss of anti-corrosion additives? Higher acid? Don’t really know. Add non-nano powdered zinc to deck paint and see less mold. Might have been a sacrificial anode inside.

 

[mcmxi]

Seems like the higher end flail mowers have larger cutting diameters and larger rollers. With so many variables of types and numbers of cutters it’s hard to compare. Several of my friends that have Asian imports don’t get the cut quality with one pass as these Alamo cutters.

Used oil might have had significant loss of anti-corrosion additives? Higher acid? Don’t really know. Add non-nano powdered zinc to deck paint and see less mold. Might have been a sacrificial anode inside.

Was the original drum filled with water to add weight? That seems very unlikely, and a sacrificial anode is only effective if it and the substrate that it's protecting are immersed in an electrolyte.

 

[Smokeydog]

Was the original drum filled with water to add weight? That seems very unlikely, and a sacrificial anode is only effective if it and the substrate that it's protecting are immersed in an electrolyte.

No, the OEM roller is not filled.