Need help with grinding tool

Sometime back I saw a message that spoke of using steel washers applied to a plaster tool for grinding. Anyone know
about this method or got any ideas or know of problems with this? Many thanks, Tony

I'm probably not the best person to answer this question, but there hasn't exactly been an outpouring of help here...

The idea is that washers can be used to very quicky hog out the initial shape of the mirror. To use this method, you need a mirror with the same size and focal ratio you are targeting (or alternatively the tool used to make the mirror.) Then you pour a plaster tool using the mirror as a mold. Now your tool has exactly the curve you want to generate, so you epoxy the washers to the surface of the tool and start grinding. The washers wear down much slower than the glass, so the initial hog-out goes very quick. I assume you can also use the washer tool for fine grinding, but I'm not sure. I also have no idea what the drawbacks are to this method.

Hope this helps.

Jeremy

I visited the gentleman's website that details grinding with steel washers. It was a quite lengthy article with a lot of pictures. Very interesting and an innovative way of grinding but different doesn't mean better and I could not discern any advantage in his method over conventional ceramic tiles. Just a different way of achieving the same end. Any claim to speed of or effectiveness in grinding time would be hard to verify. Too many variables such as substrate chosen, experience, work ethic, tool preparation, etc. A well written, interesting technique though. Wish I could find it again.

Steel washers will rust and stainless washers are too expensive. Scott is right pennies are best. They are cheaper than ceramic tile and will not scratch since they are zinc (don't use the older copper pennies). They are great for lapping but not generating. It's also not illegal.