I was referring to the typical 240 grit hone. A 400 grit hone should do a nice job for the typical do it yourselvers if done with enough care. It is reasonable to think that a polished finish may not easy to achieve by everyone wanting to repair its own hydraulic equipment. It may not be cost effective for just one repair.
However, the true surface finish required by companies that manufacture hydraulic seals for use in any type of cylinder is one that comes close to be as smooth as glass or as a chromed surface. It is true that the surface should not be perfectly polished because it will not retain oil at all. Oil will bead up and not remain in the surface as it should to provide lubrication. This lack of lubrication would cause premature wear of the seals in high speed applications and/or high usage applications with the end result of leaking seals. Also, oil could just simply bypass the seal lips as the surface may be too slippery for the seal to actually seal. It would be like when a car is waxed and the water beads run off the car. You do not want that in a cylinder. But, still, you want it to be as polished as you are able to do it. Depends on equipment, the patience of the person doing it and the technique used. It also depends on what the person doing it considers to be "good enough."
The smoother the surface, the less wear for the seals. Now, this is important in equipment which is used many hours a day, everyday, like earth moving machines, for example. For the occasional use it is not really important, as a seal would take a long time to wear with this kind of use.
I saw the link for the honers and I see that the finer grit they sell is the 400 grit. I would really like to see a 600 grit or even a 500 grit from them, but if their main business is honers for gas engines, the 600 grit would not work for that application and therefore they may never offer it as they will probably sell only a few. So they have to sell well what they have.
As for the flex hones, a 600 grit would be nice but flex hones may be rather expensive and for just one use is not worth it.
My interest with the polishing thing is that GJ members know that a well polished surface is necessary in cylinders to protect seals from excessive wear. That they can actually achieve that, at a low cost or easily, is another story. But at least they are better informed and therefore, may take better care when honing the cylinders and not just use a medium or coarse grit honer just because other persons honed their cylinders with these. ” Monkey see, monkey do” without understanding the why can affect the end result.
As for the any GJ member wanting to do its own honing, a 400 grit should do a good job of it. Just do it with care and a lot of lubrication. A 600 grit would be better, but don't go out of your way to get one. For occasional use of any type of cylinder, the surface finish achieved with a 400 grit hone is more than adequate, provided it is done correctly.
I figured thats what youns meant but had a few other ?'s. Thanks
