Rotary Cutter Refacing slip clutch plate

[BeezFun]

Burned up the disks in the slip clutch on my rotary mower. Before I put in the new ones, what's the best way to clean up the face of the clutch plates? It looks like the friction disk material melted itself to the face of the clutch, now it's covered with burned on, glazed asbestos covering a layer of rust.

 

[greg_g]

I've got two bench grinders; one with a pair of grinding wheels, one with a pair of wire wheels. The grinding wheels of course are for sharpening etc. But the wire wheels come in handy for what you need. I de-rusted and refaced my pressure plates with the coarse wire wheel, and resurfaced the friction discs with the medium wire wheel. The latter didn't amount to much more than removing scorch marks (glaze) then roughing up the friction surface.

//greg//

 

[Einar Kr]

I used a scraper and brake cleaner on mine and then with a wire brush on a battery drill, then roughed up the surface with sandpaper

 

[BeezFun]

I've got two bench grinders; one with a pair of grinding wheels, one with a pair of wire wheels. The grinding wheels of course are for sharpening etc. But the wire wheels come in handy for what you need. I de-rusted and refaced my pressure plates with the coarse wire wheel, and resurfaced the friction discs with the medium wire wheel. The latter didn't amount to much more than removing scorch marks (glaze) then roughing up the friction surface.

//greg//

I've got a heavy wire wheel on one of my hand drills, I'll try that.

 

[BeezFun]

I used a scraper and brake cleaner on mine and then with a wire brush on a battery drill, then roughed up the surface with sandpaper

Good thought, I've got the brake cleaner and the wire wheel. I was also thinking of a belt sander with really coarse grit.

 

[leonz]

:thumbsup:Just be sure to use and wear a good dust mask-that should be carborundum grit not asbestos on the old and new pads.

 

[BeezFun]

Cleaned up the faces with a combination of straight edged razor and brake cleaner, then a belt sander. The surface is pretty badly pitted with rust, to the point that the belt sander leaves large splotches like a leopords spots where the rust has eaten away steel and left a slight depression. I guess it makes sense that moisture will get in there and eventually cause this rust. I'm wondering if I should coat it with something like XO rust to stop future rusting. The rust must reduce the effective surface area between the disk and the plate, causing it to slip more easily.

 

[greg_g]

Have you considered just replacing it? Depending upon the horsepower rating, they start down around $85

//greg//

 

[buck12]

When I acquired my used tiller the slip clutch was rusted to the point that it would not slip with bolts loosened. Once I chiseled it apart I simply put it back together with bolts loosened and ran it for a few seconds letting the clutch slip. Then tightened the bolts to spec. The slipping will remove surface rust. A few pits are not going to stop it from working. The important thing is that you check it from time to time to ensure it is working properly.

 

[BeezFun]

Have you considered just replacing it? Depending upon the horsepower rating, they start down around $85

//greg//

Yes I did think of that, but check out how the slip clutch is made, see photo. Part of the yoke is manufactured as part of the slip clutch, so I'd also have to replace that half of the yoke. This thing's 50 years old, I wasn't sure I could find part of the yoke, so that would mean part or all of the PTO shaft. Anyway, for better or worse, this is where I landed.