I need to remove a bit of O.D. from Glass lens

How can I do it with out taking chips out?

I just need to turn down a glass lenas about 15 thousandths

I've done this using a diamond grit file. Or if very very minimal some fine grit sandpaper will work.

Just a few thousandths?? Old lensmakers trick--

Get a couple of Dollar Store suction cups, clean lens and stick one on each side, center as well as you can. This gives you a pair of handy handles and keeps the lens clean (mostly keeps fingers from grinding in grit). Use 120 wet-or-dry tufback paper (auto parts store). Grind away every thing that isn't needed. The suction cup handles let you try-fit as you go along. Mark high spots with magic marker, continue grindig...

I just had to take only 8 thousandths off a steel tubing section I was using for a bushing, and that turned out to be far more work than I thought it would be. (That was using a drill press and a file). If I had to take that much of a lens I'd try and mount it using something like the suction cup idea and use the finest grinding stone I could find for the dremel tool. Use a light touch and even pressure and just keep going round'. Don't think it would chip the glass but don't know if it will work well either. Hope you've got a dremel...

I've only tried it once and it didn't come out very well. I used double-sided tape to mount a saphire lens in the lathe and used a dremel tool with a diamond bit. I got a bunch of chips in the edge of the lens. My Mototool has some very tired spindle bearings and It otherwise might have worked a whole lot better. /ubbthreads/images/graemlins/icon3.gif

Larry

The hobbyists in the stained glass world grind glass all the time. Lots of it. The grinders they use are water cooled diamaond grit. If it were me I would try the suction cup idea along with my wifes glass grinder.

cheers,
zwf

I do this with plastic to make colored lens. If you find an abrasive substance to work on glass it should work as well. I take a finger screw with a flat plastic head, mount in a drill, or drill press, then hot glue the lens to the large head of the the thumb screw. This gives me rotation to keep things semetrical. The only problem with this method is that you lens is moving, and your abrasive is stationary. This can cause a burn on your abrasive material unless you keep it moving.

You might be able to use the method I used to grind down the outside of a P60 LA. You could use the suction cup idea to hold it, then run a sanding drum on a dremel around the outside. I let the drum pull itself forward so it didn't pause in one place. Don't know if it would work on glass, but I have had good luck reducing the OD of round metal that way.